Tree-growth-responsive smart banner fixing apparatus and method of operating the same

Abstract

The smart banner fixing device for responding to street tree growth according to the present invention may include: an inner contact part positioned to contact the outer surface of a street tree and adhering to the surface of the street tree; an outer sliding part positioned on the outer side of the inner contact part and coupled to allow relative movement in the radial direction according to the hypertrophic growth of the street tree; a constant load spring part connected between the inner contact part and the outer sliding part and configured to provide a constant tensile force regardless of the movement distance of the outer sliding part; and a banner fastening part coupled to the outer sliding part to fix the banner.

Description

Technology Field

[0001] The present invention relates to a smart banner fixing device that responds to the growth of street trees and a method of operation thereof. More specifically, it relates to a smart banner fixing device that responds to the growth of street trees and a method of operation thereof, wherein the fixing structure automatically expands in accordance with the hypertrophic growth of the tree while maintaining a constant pressure applied to the surface of the tree, and actively monitoring the risk conditions caused by external environmental loads and compliance with the installation permit period. Background Technology

[0003] It originates from a technical requirement to simultaneously resolve the issue of tree damage caused during the installation and maintenance of banners on street trees, as well as the safety and manageability issues of the banners.

[0004] In urban environments, banners are frequently installed along tree-lined streets for public information, promotion of local events, and commercial advertising; due to the nature of repeated installation and removal, simple fixing methods offering high work convenience have been widely used.

[0005] However, this simple fixation method fails to adequately consider the growth characteristics of trees and external environmental loads (wind loads), and tends to accumulate various side effects over time.

[0006] First, conventional methods of securing banners generally involve tying the top and bottom ends to tree trunks or supports using fastening means such as cable ties, ropes, wires, bands, buckles, or clamps. While this method provides relatively high fixing strength immediately after installation, the binding force is "fixed." Consequently, as time passes and the tree's trunk diameter increases due to hypertrophic growth, the binding points begin to constrict the bark.

[0007] As a result, the bark may be compressed or torn, which can lead to physiological damage such as vascular bundle damage, inhibition of sap flow, and localized necrosis over the long term. In particular, in structures where binding points are concentrated in a narrow area (e.g., wire, thin band), the pressure per unit area increases rapidly, exacerbating damage to trees. Conversely, if bindings are installed loosely out of concern for tree damage, the banner may sag or sway under wind load, and the binding points may detach, potentially causing falling accidents or pedestrian safety issues.

[0008] Furthermore, in urban environments, repetitive vibrations and tensile forces are applied to banners due to gusts, turbulence caused by vehicle traffic, seasonal winds, and rainfall. In conventional rigid binding structures, these loads are transmitted to the fixed point without being cushioned, and rotational torque is transmitted in the direction of the tree trunk as the banner flutters in the wind. In this case, stress accumulates in the direction of shaking or twisting of the tree trunk, and problems arise where the binding part rubs against the bark, causing frictional damage (abrasions), or the binding member digs into the bark. Consequently, conventional technology fails to structurally resolve the conflict where "tying too tightly damages the tree, while being too loose poses a safety risk."

[0009] To address these issues, some conventional technologies have proposed methods to alleviate binding force using elastic members or to absorb tension by adding springs. However, since general coil springs or rubber band-type elastic members have the characteristic that tensile force increases as the amount of displacement increases, the tensile force may actually increase as the tree grows and the binding part stretches, potentially leading to severe compression of the tree.

[0010] In other words, it is difficult to implement a mechanism where pressure remains constant while naturally expanding with growth. Furthermore, elastic members alone are insufficient to isolate or block abrupt changes in tensile force or rotational torque components caused by wind loads, which limits the ability to ensure long-term stability against repetitive vibrations.

[0011] Meanwhile, from the perspective of banner management, conventional technology makes it difficult to systematically monitor compliance with installation permit periods, unauthorized installations, and the occurrence of hazardous conditions. Local governments and management entities often rely on patrolling banner installation areas or enforcing regulations based on citizen complaints, a process that continuously incurs manpower, time, and costs.

[0012] Problems may arise such as installed banners being left unattended beyond the permitted period, banners becoming loose and at increased risk of falling after strong winds not being detected early, and on-site inspections being delayed during nighttime or emergency situations.

[0013] Recently, there have been attempts to remotely monitor conditions using sensors and communication modules; however, relying solely on simple sensor data transmission suffers from issues such as a lack of time-based logic to effectively determine "exceeded permit periods" or "dangerous conditions," or false alarms caused by instantaneous fluctuations in sensor values ​​(gusts, noise). Furthermore, if the monitoring system is not closely integrated with mechanical fixing structures, it faces limitations in that it merely monitors the trees without contributing to actual tree protection or tension stabilization.

[0014] Korean Registered Patent No. 10-2221912 discloses that the upper part of a banner is connected to a bracket on both sides of an inner ceiling using anchor bolts, a fixing part is formed on the front of the bracket to fix the upper part of the banner by magnetic force, and a fixing bar is formed longitudinally on one side of the fixing part, which is provided on one side facing a clamp that fixes the lower part of the banner, thereby allowing the banner to be installed indoors, such as in an office, in an easy and neat manner. Prior art literature

[0016] Korean Registered Patent No. 10-2221912 The problem to be solved

[0017] The present invention aims to provide a street tree growth-responsive smart banner fixing device and a method of operation thereof, wherein the fixing structure automatically expands in accordance with the hypertrophic growth of the tree while maintaining a constant pressure applied to the tree surface, and actively monitoring risk conditions due to external environmental loads and compliance with the installation permit period.

[0018] Furthermore, the present invention aims to fundamentally prevent problems such as bark compression, burrowing, and necrosis that occur during the growth process of trees due to binding methods that do not change fixing force, such as conventional ropes, steel wires, and cable ties. Additionally, the invention aims to provide a smart banner fixing device that responds to the growth of street trees and a method of operation thereof, which minimizes structural and physiological damage to trees caused by banner installation by suppressing the direct transmission of tensile force and rotational torque generated by wind load to the street trees.

[0019] In addition, the present invention aims to provide a street tree growth-responsive smart banner fixing device and a method of operation thereof, which enables the efficient management of unauthorized installations or banners exceeding the permitted period by automatically comparing and determining the tension duration and the permitted period through a tension sensor and an IoT control unit, without relying merely on visual inspection or public complaints regarding the installation status of the banner.

[0020] Furthermore, the present invention aims to provide a smart banner fixing device that responds to the growth of street trees and a method of operation thereof, which fundamentally resolves the problem of conventional technology where pressure actually intensifies as the amount of tree growth increases, by utilizing a static load spring member so that, unlike general elastic members, there is no increase in tensile force due to an increase in displacement, thereby enabling the stable achievement of the public interest objective of tree protection solely through a mechanical structure. means of solving the problem

[0022] A smart banner fixing device for responding to the growth of street trees to achieve this purpose may include: an inner contact part positioned to contact the outer surface of the street tree and adhering to the surface of the street tree; an outer sliding part positioned on the outer side of the inner contact part and coupled to allow relative radial movement according to the hypertrophic growth of the street tree; a constant load spring part connected between the inner contact part and the outer sliding part and configured to provide a constant tensile force regardless of the movement distance of the outer sliding part; and a banner fastening part coupled to the outer sliding part to fix the banner.

[0023] In one embodiment, the inner contact portion includes a plurality of curved plates having a curvature corresponding to the outer circumference shape of the tree, and the tree contact surface of the curved plates may be formed of an elastic material.

[0024] In one embodiment, the outer sliding portion may be movably coupled along a sliding guide structure formed on the inner contact portion.

[0025] In one embodiment, the outer sliding portion may include a strip-type constant load spring that provides a constant tensile force regardless of the elongation amount of the spring.

[0026] In one embodiment, the banner fastening part may be coupled to the outer sliding part via an elastic damper and a torque blocking connection part, so as to dampen the tensile force caused by wind load and block the transmission of rotational torque.

[0027] In addition, a method for fixing a banner using a smart banner fixing device that responds to the growth of roadside trees to achieve this purpose may include the steps of: closely positioning an inner contact portion on the outer surface of a roadside tree; connecting an outer sliding portion to the outer side of the inner contact portion so as to be movably radially; connecting a constant load spring portion between the inner contact portion and the outer sliding portion to set a constant tensile force regardless of the movement distance of the outer sliding portion; attaching a banner fastening portion to the outer sliding portion to fix the banner; and ensuring that the contact pressure applied to the surface of the roadside tree by the constant load spring portion remains constant while the outer sliding portion automatically moves radially in accordance with the hypertrophic growth of the roadside tree.

[0028] In one embodiment, the step of closely positioning an inner contact portion on the outer circumference of the tree may include arranging a plurality of curved plates having a curvature corresponding to the outer circumference shape of the tree in the direction of the tree's circumference, and dispersing contact pressure through an elastic material formed on the tree contact surface of the curved plates.

[0029] In one embodiment, the step of coupling an outer sliding part to the outer side of the inner contact part so as to be movable in a radial direction relative to the outer side may include the step of coupling the outer sliding part so as to be movable only in a radial direction along a sliding guide structure formed in the inner contact part.

[0030] In one embodiment, the step of connecting a constant load spring member between the inner contact member and the outer sliding member to provide a constant tensile force regardless of the movement distance of the outer sliding member may include using a strip-type constant load spring that provides a constant tensile force regardless of the elongation amount of the spring, thereby maintaining a constant contact pressure applied to the surface of the roadside tree as the outer sliding member moves.

[0031] In one embodiment, the step of fixing the banner by connecting the banner fastening part to the outer sliding part may include connecting the banner fastening part to the outer sliding part via an elastic damper and a torque blocking connection part, thereby dampening the tensile force generated by wind load and blocking the transmission of rotational torque generated by the shaking of the banner toward the roadside tree. Effects of the invention

[0033] According to the present invention, there is an advantage in that the fixing structure automatically expands in accordance with the hypertrophic growth of the tree while maintaining a constant pressure applied to the tree surface, and actively monitoring the risk condition due to external environmental loads and compliance with the installation permit period.

[0034] Furthermore, according to the present invention, problems such as bark compression, burrowing, and necrosis occurring during the growth process of trees are fundamentally prevented by binding methods that do not change fixing force, such as conventional ropes, steel wires, and cable ties. In addition, by suppressing the direct transmission of tensile force and rotational torque generated by wind load to street trees, there is an advantage of minimizing structural and physiological damage to trees caused by the installation of banners.

[0035] In addition, according to the present invention, there is an advantage in that unauthorized installations or banners exceeding the permitted period can be efficiently managed by automatically comparing and determining the tension duration and the permitted period through a tension sensor and an IoT control unit, without relying simply on visual inspection or public complaints regarding the installation status of the banner.

[0036] In addition, according to the present invention, by utilizing a static load spring, unlike general elastic members, there is no increase in tensile force with increasing displacement; thus, the problem of the conventional technology, where pressure actually intensifies as tree growth increases, can be fundamentally resolved, and the public interest objective of tree protection can be stably achieved solely through a mechanical structure. Brief explanation of the drawing

[0038] FIG. 1 is a drawing illustrating a smart banner fixing device that responds to the growth of street trees according to one embodiment of the present invention. FIG. 2 is a drawing for explaining a smart banner fixing device that responds to the growth of street trees according to another embodiment of the present invention. FIG. 3 is a flowchart illustrating an embodiment of a smart banner fixing method corresponding to the growth of roadside trees according to the present invention. FIG. 4 is a flowchart illustrating an embodiment of a smart banner fixing method corresponding to the growth of roadside trees according to the present invention. Specific details for implementing the invention

[0039] The aforementioned objectives, signatures, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0041] FIG. 1 is a drawing illustrating a smart banner fixing device that responds to the growth of street trees according to one embodiment of the present invention.

[0042] Referring to FIG. 1, the street tree growth-responsive smart banner fixing device (100) includes an inner contact part (110), an outer sliding part (120), a constant load spring part (130), a banner fastening part (140), an elastic damper (150), and a torque blocking connection part (160).

[0043] The inner contact portion (110) is a component that directly contacts the outer surface of the street tree to ensure that the banner fixing device according to the present invention is stably installed on the street tree, and forms a standard support structure for the entire device while preventing excessive pressure from being applied to the surface of the tree even during the process of the street tree's hypertrophic growth.

[0044] The inner contact portion (110) is formed of a plurality of curved plates having a curvature corresponding to the outer shape of the tree, and each curved plate is arranged to surround the outer surface of the tree.

[0045] At this time, the contact surface of the inner contact portion (110) with the tree is formed of rubber, elastomer, or a similar elastic material to prevent slipping when in contact with the surface of the tree and to disperse the contact pressure so that it is not concentrated locally. Accordingly, the inner contact portion (110) is stably maintained in close contact with the outer surface of the tree without screw fastening or through-fixing.

[0046] In one embodiment, the inner contact portion (110) may be configured such that a plurality of curved plates are connected by a hinge or sliding joint structure so as to be flexibly deformable in the circumferential direction.

[0047] According to this configuration, even if the cross-sectional shape of the street tree is elliptical rather than circular, or if localized uneven growth occurs, each curved plate can independently adjust its position to maintain a uniform contact state across the entire outer surface of the street tree.

[0048] The inner contact portion (110) acts as a reference frame to which the outer sliding portion (120) is connected so as to be relatively movable, and after installation, it maintains a state of being in close contact with the outer surface of the tree without direct radius movement despite changes in the radius of the tree.

[0049] As the growth of the roadside tree progresses and the outer diameter increases, an outer radial displacement occurs in the inner contact portion (110) in contact with the surface of the roadside tree, and this displacement is transmitted to the outer sliding portion (120) coupled to the inner contact portion (110).

[0050] The outer sliding part (120) is movably coupled along a sliding guide structure formed on the inner contact part (110), and a constant load spring part (130) is connected between the inner contact part (110) and the outer sliding part (120).

[0051] Meanwhile, during the growth process, the surface of roadside trees does not expand uniformly, and the outer surface may be unevenly deformed due to changes in bark thickness, knot formation, eccentric growth, etc. As a result, if the outer sliding part is composed of a simple straight rail structure, a jam may occur in which sliding is not performed smoothly due to localized pressure concentration or asymmetric reaction forces.

[0052] Since the constant load spring part (130) is configured to provide a constant tensile force regardless of the amount of elongation, the contact pressure applied by the inner contact part (110) to the surface of the tree is maintained constant within a set range even when the outer sliding part (120) moves. Accordingly, even if the increase in the diameter of the tree is large, the phenomenon of the bark being excessively compressed or dug into is prevented.

[0053] In another embodiment, the tree contact surface of the inner contact portion (110) may include a plurality of pressure-dispersing protrusions or uneven structures. These structures increase the contact area while forming an air layer or a micro-deformation space, thereby ensuring that the respiration or moisture exchange of the tree bark is not hindered even during long-term installation. Additionally, the hardness of the contact surface material may be selectively changed depending on the tree species or diameter range.

[0054] Meanwhile, the inner contact part (110) operates in conjunction with the outer sliding part (120), the banner fastening part (140), the elastic damper (150), and the torque blocking connection part (160) to minimize the transmission of wind load or vibration load acting on the banner to the trees.

[0055] The tensile force generated by the banner is damped through the outer sliding part (120) and the elastic damper (150) and then transmitted in the direction of the inner contact part, and in this process, the rotational torque component is blocked by the torque blocking connection part. As a result, only a limited radial compressive force is transmitted to the inner contact part (110), and no rotational load is transmitted to twist or shake the tree.

[0056] In another embodiment, the inner contact portion (110) may be designed based on a structure that is indirectly linked with a smart management system including a tension sensor. Even if the tension information measured at the outer sliding portion or the banner fastening portion exceeds a reference value or the tension duration exceeds a set range, the inner contact portion (110) continuously performs a mechanical cushioning role to maintain the contact pressure applied to the roadside tree within a certain range through a structure linked with the constant load spring portion (130).

[0057] In this way, the inner contact portion (110) functions as a key component that simultaneously satisfies the conflicting requirements of tree protection and banner fixation by being linked with a passive expansion structure without active control of external environmental changes such as the hypertrophic growth of the tree, changes in banner tension, wind load, and vibration, while maintaining a stable close contact state with the outer surface of the street tree.

[0058] The outer sliding part (120) is a key component that automatically performs an expansion operation in response to the hypertrophic growth of a street tree in the street tree growth-responsive smart banner fixing device (100) according to the present invention, and functions to stably maintain the tension of the banner while allowing radial movement relative to the inner contact part (110).

[0059] The outer sliding portion (120) is positioned along the outer circumference of the inner contact portion (110) and is coupled to move relatively along a sliding guide structure formed on the inner contact portion (110). At this time, the sliding guide structure can be implemented as a rail-slot type, a guide groove and protrusion type, or a guide surface type of an overlapping curved plate, and guides the outer sliding portion (120) to move only in the radial direction without deviating or twisting in the circumferential direction.

[0060] In the initial installation state, the outer sliding part (120) is positioned with a constant load spring part (130) connected between it and the inner contact part (110), and maintains a state in which it is elastically pulled toward the inner contact part (110) according to a constant tensile force set by the constant load spring part (130). As a result, the outer sliding part (120) performs the role of maintaining the contact pressure acting on the outer surface of the tree at a set value in cooperation with the inner contact part (110).

[0061] As the growth of the roadside tree progresses and the outer diameter increases, a radial displacement occurs in the outward direction while the inner contact portion (110) remains in close contact with the surface of the roadside tree. This radial displacement is transmitted to the outer sliding portion (120), and the outer sliding portion (120) moves outward along the sliding guide structure while maintaining the tension of the static load spring portion (130).

[0062] The outer sliding part (120) includes a self-aligning member that allows a small degree of freedom in a direction orthogonal to the sliding direction in correspondence with the non-uniform shape of the outer surface of the tree.

[0063] The self-aligning member performs the function of automatically correcting the alignment state of the outer sliding part so that sliding movement is not hindered even when an asymmetric load is applied to the outer sliding part due to the hypertrophic growth of the roadside tree.

[0064] During the growth process, the outer surface of roadside trees may not expand uniformly, but may instead exhibit a shape that becomes larger in a specific direction or protrudes locally. Due to such eccentric growth or surface irregularities, lateral reaction forces or torsional components other than the radial direction may act on the outer sliding part. If the sliding structure is formed as a fully constrained structure, such asymmetric loads increase the contact pressure with the sliding guide, significantly increasing frictional resistance, and ultimately causing increased movement resistance or jamming.

[0065] The self-aligning member according to the present invention resolves this problem by allowing a minute degree of freedom in a direction orthogonal to the sliding direction. When the outer sliding part is about to be deflected due to a local protrusion on the outer surface of the tree, the self-aligning member allows a minute displacement or minute angle rotation in that direction, thereby allowing the contact surface of the outer sliding part to naturally realign with the tree surface. Accordingly, excessive lateral pressure is not generated on the sliding guide, and the phenomenon of a sudden increase in sliding resistance is suppressed.

[0066] In addition, even when different reaction forces act on both sides of the outer sliding part due to the eccentric growth of the roadside tree, the self-aligning member redistributes the load distribution to restore the contact state with the sliding guide to a balanced state. Since the degree of freedom in the sliding direction is maintained during this process, the constant tensile force provided by the constant load spring part (130) is not affected, and the radial expansion movement continues.

[0067] The self-aligning member can perform an alignment correction function by at least one of elastic deformation, clearance movement, or spherical contact, and can be configured to restore to its original reference alignment state when an external load is removed. In this way, the self-aligning member actively absorbs and corrects asymmetric loads occurring in the non-uniform growth environment of street trees without hindering sliding movement.

[0068] As a result, the self-aligning member prevents sliding sticking that may occur in a long-term outdoor environment and ensures that the outer sliding part moves smoothly in the radial direction according to the growth of the roadside tree, thereby stably securing a constant contact pressure condition maintained by the constant load spring part (130).

[0069] Since the constant load spring part (130) provides a constant tensile force regardless of the amount of elongation, the tension acting between the inner contact part (110) and the outer sliding part (120) remains constant even if the amount of movement of the outer sliding part (120) increases.

[0070] Accordingly, the outer sliding part (120) automatically expands in proportion to the increase in diameter of the street tree, while performing a stable tension maintenance function so that the tension acting on the banner does not rapidly increase or decrease. As a result, the outer sliding part (120) acts as a mediating member that simultaneously satisfies the function of responding to street tree growth and the function of fixing the banner.

[0071] In one embodiment, the outer sliding portion (120) may be composed of a plurality of segmented sliding plates and arranged in a circumferential direction. According to this configuration, even if local growth deviations occur on the outer circumference of the roadside tree, each segmented sliding plate can move independently to maintain the alignment of the entire structure.

[0072] In another embodiment, the outer sliding part (120) may further include an extension limiting part that limits the maximum travel distance. This limiting part may be implemented in the form of a stopper, a stopper, or a deformation-preventing rib, and structural stability is ensured by preventing the outer sliding part (120) from moving beyond a set maximum radius.

[0073] In another embodiment, the outer sliding part (120) may be integrally or detachably coupled with the banner fastening part (140). When formed integrally with the banner fastening part (140), the outer sliding part (120) has a structure that directly receives the tensile force transmitted from the banner, and when it is a detachably coupled structure, it may be configured to be connected to the banner fastening part (140) via an elastic damper and a torque blocking connection so that wind load and vibration load are dampened before being transmitted to the outer sliding part (120).

[0074] In another embodiment, a tension sensor is positioned on the outer sliding part (120) to measure the tension acting on the banner directly or indirectly. In this case, the degree of growth of the roadside trees, the installation status of the banner, or whether there is an abnormality in tension can be determined more precisely by combining the change in the movement position of the outer sliding part (120) and the measurement value of the tension sensor. This tension information can be transmitted to an external management server via a communication module and can be used for automatic enforcement or maintenance decisions.

[0075] Meanwhile, the outer sliding part (120) is designed to minimize the direct transmission of wind load or vibration load generated by the banner to the inner contact part (110). The outer sliding part (120) is linked with an elastic damper and a torque blocking connection part so that the tensile force component is transmitted in a damped state and the rotational torque component is blocked, thereby ensuring that only a limited radial load is transmitted to the inner contact part (110).

[0076] In this way, the outer sliding part (120) performs a passive expansion function that automatically adjusts its position according to the hypertrophic growth of the street tree, and at the same time functions as a core component that provides a structural basis for maintaining banner tension, damping wind load, and linking with a smart management system.

[0077] The constant load spring part (130) is a key component of the banner fixing device according to the present invention that allows the movement of the outer sliding part (120) in response to the hypertrophic growth of the street tree, while maintaining a constant tension acting on the surface of the street tree and the banner.

[0078] Unlike a general coil spring in which the tensile force increases in proportion to the elongation amount, the constant load spring (130) is configured to continuously provide a tensile force within a set range regardless of the amount of displacement of the spring.

[0079] The constant load spring part (130) has one end connected to the inner contact part (110) and the other end connected to the outer sliding part (120), and extends or unwinds in conjunction with the outer sliding part (120) when it moves radially relative to the inner contact part (110).

[0080] At this time, since the constant load spring part (130) maintains a constant tensile force regardless of the movement distance of the outer sliding part (120), even if the outer diameter of the tree increases, the contact pressure applied by the inner contact part (110) to the surface of the tree remains constant within a set range.

[0081] When the outer sliding part (120) moves outward as the growth of the roadside tree progresses, the constant load spring part (130) maintains the magnitude of the tensile force almost constant while the winding state of the spring is gradually released.

[0082] Accordingly, even if the growth of street trees is extensive or accumulates over a long period, the pressure acting on the bark does not gradually increase but remains stable. This contributes to preventing the bark from necrotizing or rupturing due to prolonged pressure.

[0083] In one embodiment, the constant load spring portion (130) may be composed of a strip-type constant load spring in which a metal strip is wound in the form of a drum, and this structure has the advantage of being able to provide a constant tensile force even with a relatively long stroke. In this case, the winding drum of the spring may be positioned to be rotatably supported on either the outer sliding portion (120) or the inner contact portion (110).

[0084] In another embodiment, a plurality of constant load springs (130) may be arranged in parallel or in series. In the case of parallel arrangement, the magnitude of the provided tensile force can be increased, and in the case of series arrangement, the allowable travel distance can be increased. Through this, the characteristics of the constant load springs (130) can be selectively designed according to the tree species, diameter range, or banner load conditions.

[0085] In another embodiment, the constant load spring portion (130) may further include a friction control member or a damping member. This configuration gently controls the movement speed of the outer sliding portion (120), thereby preventing the outer sliding portion (120) from moving instantaneously due to sudden wind loads or external impacts. As a result, the shaking of the banner is mitigated and the overall stability of the device is improved.

[0086] Meanwhile, the static load spring (130) is linked with the outer sliding part (120) and the elastic damper to perform a cushioning function against wind load and vibration load. Even if a change in the tensile force acting on the banner occurs, the static load spring (130) automatically corrects the position of the outer sliding part (120) so as not to exceed the set tensile force range, and the minute displacement occurring in this process is further damped by the elastic damper.

[0087] In another embodiment, the operating state of the constant load spring part (130) can be indirectly monitored through a tension sensor or a position sensor placed on the outer sliding part (120). In this case, the tension maintenance state or change in the amount of movement of the constant load spring part (130) can be analyzed by a smart management system and used to determine whether the device is operating normally.

[0088] In this way, the constant load spring part (130) enables automatic expansion operation according to the hypertrophic growth of the street tree, while also performing the function of maintaining constant tension acting on the surface of the street tree and the banner, thereby functioning as a core mechanism that simultaneously satisfies the conflicting demands of tree protection and banner fixation.

[0089] Since the above-mentioned constant load spring part (130) is configured to continuously provide a constant tensile force, a relatively large tensile resistance may occur during the process of attaching the banner while the worker artificially maintains the outer sliding part in an extended state during initial installation.

[0090] Meanwhile, since the constant load spring part (130) is configured to continuously provide a constant tensile force, a relatively large tensile resistance may occur during the process of attaching the banner while the worker artificially maintains the outer sliding part in an extended state during initial installation. Such tensile resistance makes it difficult for the worker to attach the banner while holding the outer sliding part with one hand, and there is a risk of reducing work safety, especially when working at heights or installing in confined spaces.

[0091] To improve this, the present invention may further include an initial tension setting member configured to maintain the outer sliding part (120) in a temporary extended state. The initial tension setting member performs the function of fixing the outer sliding part so that it does not automatically contract by temporarily supporting or blocking the restoring force of the static load spring part when the outer sliding part (120) is moved to an extended position required for installation.

[0092] During the installation process, the operator extends the outer sliding part radially to align it with the outer surface of the tree, and upon reaching the desired position, activates the initial tension setting mechanism to temporarily fix the position. At this time, since the tensile force of the static load spring is supported by the initial tension setting mechanism, the operator can perform the banner fastening operation in a free state without the need to continuously pull the spring.

[0093] The above initial tension setting member can be implemented in various forms, such as a locking structure capable of fixing the movement position of the outer sliding part in stages, a locking structure using an insertable fixing member, a cam structure that maintains tension through rotational movement, or a structure that is temporarily fixed by lever operation.

[0094] The banner fastening part (140) is a component that directly supports the banner in the banner fixing device according to the present invention and initially receives the load generated by the external environment, and performs the role of controlling and buffering the load transmitted to the roadside tree along with the stable fixing of the banner.

[0095] The banner fastening part (140) is coupled to and positioned on the outer sliding part (120) and can be formed as a hook, clamp, bar, or equivalent fastening structure to secure the upper or lower edge of the banner. The banner fastening part (140) is configured to allow for selective fastening depending on the material, thickness, and installation method of the banner, and can be formed to be detachable without a separate tool when replacing the banner.

[0096] When a wind load is applied to the banner due to external wind, rain, or vibration while the banner is fastened, the load is transmitted in the direction of the outer sliding part (120) through the banner fastening part (140). At this time, the banner fastening part (140) is not directly rigidly connected to the outer sliding part (120), but is connected via an elastic damper and a torque blocking connection part, thereby separating and processing the tensile force and rotational torque components in the load transmission path.

[0097] Specifically, the tensile force component generated by the banner is absorbed and damped through an elastic damper and transmitted to the outer sliding part (120). The elastic damper can be formed of a viscoelastic material or a hydraulic or friction-based damping structure, and gently mitigates sudden changes in tensile force caused by instantaneous gusts of wind or repetitive vibrations. Accordingly, the load transmitted to the outer sliding part (120) and the static load spring part (130) is maintained within a stable range without sudden peak values.

[0098] Meanwhile, the rotational or torsional components of the wind load acting on the banner are blocked by the torque-blocking connection. The torque-blocking connection can be formed with a structure that allows rotational freedom or selectively allows rotation only in a specific direction, and can be implemented as a pin-bushing structure, a flexible link, or a universal coupling structure. As a result, the transmission of rotational torque generated by the shaking of the banner to the outer sliding part (120) and the inner contact part (110) is suppressed, and the phenomenon of the roadside tree twisting or shaking is prevented.

[0099] In one embodiment, the banner fastening part (140) is formed integrally with the outer sliding part (120) to ensure structural simplicity. In this case, the elastic damper and torque blocking functions can be implemented by an intermediate coupling part positioned inside the fastening part or between the fastening part and the outer sliding part.

[0100] In another embodiment, the banner fastening part (140) may be provided in the form of a module that is separable from the outer sliding part (120). According to this configuration, only the banner fastening part (140) can be selectively replaced or maintained, thereby improving ease of management. Additionally, fastening parts having different damping characteristics can be selectively applied depending on the banner size or load conditions.

[0101] In another embodiment, a tension sensor is embedded in the banner fastening part (140) to directly measure the tensile force acting on the banner. The tension sensor detects the tensile force transmitted to the banner fastening part in real time or periodically, and the detected tension information can be transmitted to an external management server via a communication module. In this case, the banner fastening part (140) functions as a smart management interface that monitors the installation status and usage period of the banner, going beyond a simple mechanical fastening means.

[0102] In another embodiment, the banner fastening unit (140) may be linked with control logic for calculating the duration of the tensile force measured by the tension sensor. If the set tension threshold is maintained for a certain period of time or longer, the banner fastening unit (140) may determine the state as a violation condition, generate an alarm signal, and transmit it to a management server. Through this, unauthorized installation of the banner, exceeding of the permit period, or a dangerous state can be automatically detected.

[0103] In this way, the banner fastening part (140) functions as a core component that comprehensively achieves the purpose of the invention, which is to protect street trees and manage banners, by performing the basic function of stably fixing the banner, as well as wind load damping, rotational torque blocking, tension detection, and smart management functions, in cooperation with the outer sliding part (120) and the inner contact part (110).

[0104] The elastic damper (150) is a cushioning component that absorbs and mitigates wind loads, vibration loads, and instantaneous impact loads acting on the banner in the banner fixing device, thereby preventing the loads from being directly transmitted to the outer sliding part (120) and the inner contact part (110). The elastic damper (150) is positioned between the banner fastening part (140) and the outer sliding part (120) and acts as a mechanical filter on the transmission path of the load flowing in from the banner.

[0105] When wind acts on a banner, a repetitive vibration component due to shaking is generated along with a load in the tensile direction. This load is transmitted to an elastic damper (150) through a banner fastening part (140), and the elastic damper (150) smoothly controls the magnitude and rate of change of the load through its own elastic deformation and damping characteristics. In this process, the elastic damper (150) reduces the instantaneous peak value of the tensile force and dissipates some of the energy resulting from the repetitive vibration in the form of heat or internal friction.

[0106] The elastic damper (150) may be formed from a viscoelastic material, a rubber-based elastomer, a polyurethane-based material, or a material having damping characteristics equivalent thereto, and may be designed to exhibit hysteresis characteristics when deformed.

[0107] Consequently, even under identical load conditions, different responses are exhibited during the rising and falling sections of the load, thereby suppressing resonance phenomena caused by repetitive vibrations. This viscoelastic behavior contributes to maintaining structural stability in environments where the banner is continuously swayed by the wind.

[0108] In one embodiment, the elastic damper (150) may be formed as a linear damper structure that deforms in the tensile direction. In this case, when the tensile force transmitted from the banner fastening part (140) increases, the elastic damper (150) extends, and when the tensile force decreases, it returns to its original length. At this time, the elastic damper (150) provides a damping force proportional to the rate of change of the tensile force, thereby preventing a sudden change in tension from being transmitted to the outer sliding part (120).

[0109] In another embodiment, the elastic damper (150) may be formed as a structure that operates in a shear deformation manner. In this case, when relative displacement occurs between the banner fastening part (140) and the outer sliding part (120), the elastic damper (150) absorbs energy while deforming in the shear direction. This shear type damper structure has an excellent damping effect for repetitive small vibrations, making it advantageous for suppressing micro-vibrations in urban environments.

[0110] In another embodiment, the elastic damper (150) may be implemented as a composite damping structure combined with a fluid damper or a friction damper. In this case, the elastic element allows for initial deformation, and the fluid or friction element provides additional damping force according to the deformation rate, thereby ensuring stable damping characteristics for both low-speed and high-speed displacements.

[0111] The elastic damper (150) operates in cooperation with the constant load spring part (130) and the outer sliding part (120) so that changes in tensile force caused by wind load do not immediately disturb the tension state of the constant load spring part (130).

[0112] That is, the elastic damper (150) preferentially absorbs the load of short-term, high-frequency components and transmits only the displacement of long-term, low-frequency components to the outer sliding part (120) and the constant load spring part (130), thereby enabling the constant load spring part (130) to stably perform the originally intended constant tension maintenance function.

[0113] Additionally, the elastic damper (150) is linked with the torque-blocking connection to help suppress the transmission of rotational load components. The torsional load generated by the shaking of the banner is partially absorbed during the deformation process of the elastic damper (150) or separated into directional loads by the torque-blocking connection and is not transmitted to the outer sliding part (120) and the inner contact part (110). As a result, only limited radial compressive force is transmitted to the roadside trees, thereby maximizing the tree protection effect.

[0114] In this way, the elastic damper (150) absorbs and dampens various types of external loads acting on the banner, thereby stabilizing the load transfer characteristics of the entire device and functioning as a key cushioning component that contributes to preventing damage to trees, improving the stability of the banner, and ensuring long-term reliability of the device.

[0115] The torque blocking connection part (160) is a component that blocks the transmission of rotational torque components generated by wind load or vibration acting on the banner in the banner fixing device according to the present invention to the direction of the roadside tree, and performs the role of controlling the transmission path by separating the tensile force and the rotational load.

[0116] The torque blocking connection part (160) is positioned between the banner fastening part (140) and the outer sliding part (120), and forms a structurally separated connection so that the radial tensile force component of the load transmitted through the banner fastening part is allowed, while the rotational torque component generated by the shaking or twisting of the banner is not transmitted to the outer sliding part and the inner contact part.

[0117] When wind acts on the banner, the banner sways left and right or forward and backward, generating a complex load that includes a rotational component along with tensile force. At this time, the torque blocking connection part (160) prevents the rotational movement of the banner fastening part from being rigidly transmitted to the outer sliding part through a structure that selectively allows rotational degrees of freedom or absorbs and disperses rotational force. As a result, only the axial component of the tensile force transmitted from the banner is transmitted to the outer sliding part, and torsion or rotational loads are blocked.

[0118] In one embodiment, the torque blocking connection (160) may be formed as a pin-bushing structure. In this case, the banner fastening part is supported to allow limited rotation around the pin, and the bushing is fixed to the outer sliding part so that rotational torque is not directly transmitted. The gap or elastic material between the pin and the bushing absorbs friction and shock generated during rotation, thereby mitigating fatigue damage caused by repetitive shaking.

[0119] In another embodiment, the torque blocking connection (160) may be implemented in the form of a flexible link or a flexible connection. In this structure, even if the banner fastening part is slightly tilted or rotated, the flexible link deforms to absorb the rotational component and reduce the torque transmitted to the outer sliding part. In this case, the length, thickness, and elastic modulus of the link may be selectively set according to the size of the banner or expected wind load conditions.

[0120] In another embodiment, the torque blocking connection (160) may be formed as a universal joint or a spherical coupling structure. In such a structure, the banner fastening part has a degree of rotational freedom in multiple axial directions, and only linear tensile force is transmitted to the outer sliding part. Accordingly, rotational torque is not accumulated in the direction of the roadside tree even when the banner is swaying in multiple directions.

[0121] The torque blocking connection (160) works in conjunction with the elastic damper to gradually mitigate the load transfer caused by wind load. That is, the tensile force component is primarily damped by the elastic damper and then transmitted to the outer sliding part, while the rotational component is structurally blocked by the torque blocking connection (160). Due to this separation structure, only a limited radial load is transmitted to the outer sliding part and the inner contact part, and stress in the direction of twisting or shaking the tree trunk is substantially eliminated.

[0122] In another embodiment, the torque blocking connection (160) may include a friction control structure. In this case, rotation is not completely free, but rotation is allowed below a certain threshold torque, and rotation is restricted by friction or a stopper when the threshold torque is exceeded. Through this, small vibrations can be naturally absorbed, while excessive rotation caused by strong winds can be suppressed.

[0123] In this way, the torque blocking connection part (160) prevents the rotational load generated at the banner fastening part from being transmitted to the outer sliding part and the inner contact part, thereby fundamentally reducing the torsional stress transmitted to the roadside tree and preventing frictional damage to the bark and long-term damage to the tree. In addition, through a structure that separates and processes tensile force and rotational load, it provides a mechanical protection function so that the automatic expansion and tension maintenance mechanism according to the present invention can operate stably.

[0125] FIG. 2 is a drawing for explaining a smart banner fixing device that responds to the growth of street trees according to one embodiment of the present invention.

[0126] Referring to FIG. 2, the smart banner fixing device for street tree growth may further include an IoT control unit (170) and a tension sensor (180).

[0127] The IoT control unit (170) operates to actively monitor the tension status of the banner and compliance with the installation period, and to generate an alarm in case of violation. The IoT control unit (170) is electrically connected to a tension sensor (180) and a communication module placed in the banner fastening unit (140) or an adjacent area, and can receive additional auxiliary information from a position sensor or a movement amount sensor placed in the outer sliding unit (120) as needed.

[0128] The IoT control unit (170) receives a sensor signal corresponding to the tension force of the banner from the tension sensor (180) and converts the signal into a tension value. For example, if the tension sensor (180) is based on a strain gauge, the IoT control unit (170) amplifies and filters the bridge circuit output voltage and then converts it into a tension value according to a correction factor.

[0129] In addition, so that spike signals caused by momentary shaking of the banner or gusts of wind are not mistaken for violation judgments, the IoT control unit (170) applies a moving average, a median filter, or a low-pass filter to the tension value to generate a stabilized tension estimate value.

[0130] The IoT control unit (170) continuously determines whether the stabilized tension estimate is greater than or equal to a preset tension threshold and calculates the cumulative time during which the state of being greater than or equal to the tension threshold is maintained.

[0131] At this time, the IoT control unit (170) does not rely solely on the magnitude of tension at a single point in time, but uses the time during which tension is “continued” above a certain level as a key judgment indicator. To this end, the IoT control unit (170) updates whether the tension threshold is exceeded in a binary state at each measurement cycle, and calculates the tension duration based on [Equation 1] by accumulating the length of the interval where the exceeded state is continuous.

[0133] [Mathematical Formula 1]

[0134]

[0135] D T : Tension duration,

[0136] Tth: Pre-set tension threshold,

[0137] : Filtered tension estimate at time t,

[0138] 1(): An indicator function that outputs 1 if the condition is true and 0 if it is false,

[0139] [t0, t1]: Tension monitoring time interval

[0141] [Equation 1] performs the function of quantifying, in terms of the length of time, how long the state in which the filtered tension estimate is above the tension threshold value persists during the tension monitoring time interval.

[0142] In other words, by considering the temporal duration during which tension is maintained above a reference value, rather than judging solely based on the magnitude of tension at a single point in time, it becomes possible to exclude false detections caused by instantaneous wind loads or noise and to make stable violation judgments.

[0143] The tension duration defined in this way is compared by the IoT control unit with permit period information or risk standard time, and is utilized as a key judgment indicator to determine whether the banner has exceeded its permit period, is in a safety risk state, or is subject to enforcement.

[0144] The IoT control unit (170) obtains permission period information to determine whether the installation permission period is being complied with, separate from the tension duration. The permission period information can be expressed as the time of installation, the time of termination, or the number of permitted days, and can be stored in a storage unit inside the IoT control unit (170) or downloaded from a management server and maintained in a cached form.

[0145] For example, the IoT control unit (170) loads a permission period table mapped to a device identifier and calculates the permission expiration time based on the current time (built-in clock or server synchronization clock).

[0146] In addition, in preparation for cases where permission period information is updated, the IoT control unit (170) can periodically synchronize with the server or receive update events pushed from the server to update the stored permission period information.

[0147] The IoT control unit (170) determines whether there is a violation by comparing the calculated tension duration and permission period information. In one embodiment, the IoT control unit (170) determines that if a state exceeding the tension threshold is detected even after the permission expiration time, it is an “installation exceeding the permission period.”

[0148] In another embodiment, the IoT control unit (170) determines a “safety risk state” when the tension value remains above a risk threshold for a certain period of time, even within the permitted period. Here, the risk threshold can be set according to the banner material, fastening method, and on-site wind conditions, and a case where the rate of change in tension is rapid (e.g., a rapid increase in tension within a short period) can also be determined as a risk event.

[0149] Additionally, the IoT control unit (170) can classify cases where the sensor signal is stuck in an abnormal range for a long time or only noise exists as a diagnostic event to determine whether the tension sensor is faulty or disconnected.

[0150] When a violation or dangerous state is determined, the IoT control unit (170) generates an alarm signal and transmits it to a management server via a communication module. The alarm signal may include at least some of the following: a device identifier, a time of occurrence, a type of violation (exceeding the permitted period, continued dangerous tension, sensor malfunction, etc.), a tension value or duration of tension, and installation location information.

[0151] Installation location information can be obtained from a location positioning module connected to the IoT control unit (170), and if there is no separate location positioning module, fixed location information registered at the time of installation can be used. The management server can perform field inspection requests, maintenance notifications, or enforcement tasks according to the received alarm signal.

[0152] The IoT control unit (170) may include local storage and retransmission functions so that monitoring functions continue even in the event of communication failure or power shortage.

[0153] In one embodiment, the IoT control unit (170) stores the event in non-volatile memory when an alarm event occurs but communication is not possible, and sequentially retransmits the stored event when communication is restored.

[0154] In another embodiment, the IoT control unit (170) can perform adaptive sampling by operating in a low-power mode during normal operation and switching to an active mode only when the change in tension exceeds a certain threshold to increase the measurement cycle. This enables long-term operation even with battery-based operation.

[0155] Additionally, the IoT control unit (170) can interpret the amount of movement or position change of the outer sliding part (120) together with tension data, taking into account interoperability with the mechanical automatic expansion structure. For example, if the tension is maintained within a certain range even though the position of the outer sliding part (120) shows a long-term increasing trend due to the growth of roadside trees, it can be determined as a normal state; conversely, if the tension increases abnormally while there is almost no movement of the outer sliding part (120), it can be determined as a fastening failure or interference from an obstacle. This fusion judgment contributes to reducing false alarms and increasing the accuracy of fault diagnosis compared to simple tension monitoring.

[0156] In this way, the IoT control unit (170) performs a series of control logics including tension estimation and stabilization based on the tension sensor (180), calculation of tension duration, loading and comparison of permission period information, determination of violation / risk events, transmission of alarm signals, response to communication failures, and low-power operation, thereby combining with the tree protection function provided by the power-free automatic expansion mechanism to realize the technical feature of the present invention, “combination of passive expansion and active monitoring.”

[0157] The tension sensor (180) is a component that detects the tensile force acting on the banner in the banner fixing device and provides basic data for determining the installation status, safety status, and compliance with the permit period of the banner. The tension sensor (180) is positioned at the banner fastening part (140) or in an adjacent area and is configured to detect the tensile force transmitted from the banner directly or indirectly.

[0158] When external wind, rain, vibration, or environmental changes occur while the banner is fixed to the banner fastening part (140), a load in the tensile direction is generated on the banner, and this load is transmitted to the tension sensor (180) through the fastening part. The tension sensor (180) converts this mechanical load into an electrical signal and outputs it. At this time, the tension sensor (180) can be implemented in various sensor structures such as a strain gauge type, a load cell type, a piezoelectric element type, or a fiber optic-based sensor type, and depending on each method, a change in resistance, a change in voltage, or a change in optical signal proportional to the tensile force occurs.

[0159] In one embodiment, the tension sensor (180) includes an elastic member to which a strain gauge is attached, and the elastic member is slightly deformed according to the tensile force acting on the banner fastening part, and accordingly, the resistance value of the strain gauge changes. The tension sensor (180) converts this change in resistance into a voltage signal through a bridge circuit and outputs it, and the voltage signal is transmitted to the IoT control unit (170).

[0160] The IoT control unit (170) performs amplification, noise removal, and filtering processing on the raw signal received from the tension sensor (180) to calculate a stabilized tension estimate. At this time, the filtering processing may be performed using a moving average filter, a low-pass filter, or a median filter, and prevents spike signals caused by gusts of wind or instantaneous vibrations from being mistaken for the actual tension state. The tension estimate with filtering applied is continuously updated over time.

[0161] The tension sensor (180) can be used to detect not only the magnitude of the tensile force acting on the banner, but also the pattern of change in tension. For example, if the tension value increases or decreases rapidly, or if it vibrates repeatedly within a certain range, the pattern can be interpreted as an indicator suggesting an increase in wind load, a failure in fastening, or the possibility of external interference. The IoT control unit (170) can analyze this pattern of tension change to determine a dangerous state or an abnormal state.

[0162] In another embodiment, the tension sensor (180) may be combined with a structure that indirectly detects a change in position or amount of movement of the outer sliding part (120). In this case, by analyzing the information on the amount of movement of the outer sliding part (120) and the measurement value of the tension sensor (180) together, it is possible to distinguish between normal expansion movement and abnormal tension increase due to the hypertrophic growth of the roadside tree.

[0163] For example, a case where the tension value remains constant despite the movement of the outer sliding part (120) increasing can be determined as a normal state, and a case where the tension value increases rapidly despite almost no change in movement can be determined as an abnormal fastening state.

[0164] In another embodiment, the tension sensor (180) may be configured to operate on a fixed periodic or event-based basis. Normally, it operates in a low-power mode, and when the change in tension is minimal, the measurement cycle is lowered, and when the change in tension exceeds a threshold, the measurement cycle is increased to perform more precise monitoring. This enables stable monitoring for a long period even in a battery-based operating environment.

[0165] Tension information calculated from the tension sensor (180) is utilized by the IoT control unit (170) for control logic such as calculating the tension duration, comparing permission periods, and determining a dangerous state. In particular, since the temporal duration during which the tension is maintained above a threshold value, rather than a tension value at a single point in time, is used as the judgment criterion, false alarms caused by temporary disturbances are reduced, and highly reliable management becomes possible.

[0166] Additionally, the tension sensor (180) can perform a self-diagnosis function. For example, if the output of the tension sensor (180) is fixed at a certain value for a long time or exceeds a physically possible range, the IoT control unit (170) can determine that the sensor is disconnected, detached, or in a faulty state and generate a separate diagnosis event. This diagnosis information can be transmitted to a management server and used to determine maintenance.

[0167] In this way, the tension sensor (180) functions as a key component for realizing the active monitoring function of the present invention by performing the role of connecting the mechanical automatic expansion structure and the judgment logic of the IoT control unit as a key input means for quantitatively detecting the tensile force acting on the banner and analyzing the temporal change characteristics thereof.

[0169] FIG. 3 is a flowchart illustrating an embodiment of a smart banner fixing device that responds to the growth of street trees according to the present invention.

[0170] Referring to FIG. 3, in step S110, a standard support structure of the device is formed around the inner contact portion (110) and the device is pressed against the surface of the street tree so that the street tree growth-responsive smart banner fixing device (100) can be stably fixed to the outer surface of the street tree.

[0171] When an installer of the street tree growth-responsive smart banner fixing device (100) selects an installation section of a street tree, the inner contact portion (110) is positioned to have a curvature corresponding to the outer shape of the street tree and takes the form of wrapping around the street tree.

[0172] In an embodiment where the inner contact portion (110) is composed of a plurality of curved plates, the position of each curved plate is adjusted so as to sequentially contact the outer surface of the tree, and the connecting portion between the plates is naturally aligned along the shape of the outer surface of the tree (circular, elliptical, or local irregularities).

[0173] At this time, the inner contact portion (110) is not based on penetrating fastening or fastening that penetrates the bark, and is configured to ensure close contact within a range where no slippage occurs while minimizing pressure on the surface of the tree. An elastic contact layer is formed on the tree contact surface of the inner contact portion (110), which causes elastic deformation against the fine irregularities on the surface of the tree and secures surface contact.

[0174] Accordingly, the concentration of contact pressure at a narrow point is suppressed, and the contact area is expanded, thereby reducing the pressure per unit area. Additionally, since the elastic contact layer increases the coefficient of friction, the phenomenon of the inner contact part (110) rotating or sliding on the surface of the roadside tree is suppressed even when the banner is not yet fastened immediately after installation or when the wind is weak. If necessary, the contact surface of the inner contact part (110) may include an uneven pattern, anti-slip protrusions, or a porous structure to further improve contact stability.

[0175] With the inner contact portion (110) in close contact with the outer surface of the street tree, the direction and position in which the outer sliding portion (120) is coupled to the inner contact portion (110) of the street tree growth-responsive smart banner fixing device (100) are set, and a reference position in which the constant load spring portion (130) can be connected is determined.

[0176] That is, since the contact quality of the inner contact portion (110) in step S110 determines the overall operational stability of the smart banner fixing device (100) that responds to the growth of the street tree, the inner contact portion (110) is arranged so that the contact state with the outer surface of the street tree is maintained uniformly, and is adjusted so that the gap between the plates is not excessively widened or a specific point is overcompressed.

[0177] Additionally, in step S110, the inner contact portion (110) is configured to form a “standard contact” state rather than tightening the surface of the tree to protect the tree. That is, the inner contact portion (110) provides a support structure that serves as a standard for a certain contact pressure set by the constant load spring portion (130) in a subsequent step, and prevents excessive tension from being applied at the time of installation.

[0178] This prevents the inner contact portion (110) from becoming fixed in a direction that compresses the bark even as the roadside tree grows larger, and forms mechanical initial conditions in which the automatic expansion function can be normally expressed by the relative movement of the outer sliding portion (120) and the provision of a constant tensile force by the static load spring portion (130).

[0179] In step S120, based on the inner contact part (110) that is in close contact with the outer surface of the street tree in step S110, the outer sliding part (120) is connected to allow relative movement and the constant load spring part (130) is connected to set the basic tension condition of the street tree growth-responsive smart banner fixing device (100).

[0180] With the inner contact portion (110) in a stable contact with the outer surface of the tree, the outer sliding portion (120) is positioned on the outer side of the inner contact portion (110) and coupled so as to be movable in the radial direction.

[0181] To this end, a rail, groove, protrusion, or a sliding guide structure equivalent thereto is formed on at least one side of the inner contact portion (110) or the outer sliding portion (120), and the outer sliding portion (120) is restricted so that rotation or deviation does not occur while moving along the sliding guide structure. As a result, the outer sliding portion (120) is induced to follow only the radial displacement caused by the hypertrophic growth of the roadside tree.

[0182] When the outer sliding part (120) is slidably coupled to the inner contact part (110), a constant load spring part (130) is connected between the inner contact part (110) and the outer sliding part (120). The constant load spring part (130) may be formed as a strip-type constant load spring, a roll-type constant load spring, or a structure equivalent thereto, and is designed to provide a constant tensile force regardless of the amount of elongation.

[0183] The constant load spring portion (130) is positioned to be tensioned in the direction in which the outer sliding portion (120) moves outward, thereby preventing the outer sliding portion (120) from being excessively disengaged from the inner contact portion (110) while providing a constant restoring force.

[0184] During the tension setting process, the installer sets the basic tension applied to the street tree growth-responsive smart banner fixing device (100) by adjusting the initial connection position or mounting position of the static load spring part (130). This basic tension acts as a reference value for the contact pressure applied to the street tree surface by the inner contact part (110) and the banner tension to be transmitted through the banner fastening part (140).

[0185] At this time, the basic tension can be set considering the tree species, diameter, bark condition, and installation environment of the street tree, and is set to a range in which the street tree growth-responsive smart banner fixing device (100) can be stably maintained against external loads without pressing on the surface of the street tree.

[0186] When the constant load spring part (130) is connected and the basic tension is set, the outer sliding part (120) maintains a state in which it is pulled with a constant tensile force against the inner contact part (110).

[0187] Subsequently, even when the outer sliding part (120) moves outward due to the hypertrophic growth of the tree, the constant load spring part (130) does not increase the tensile force according to the elongation amount and remains constant, so the contact pressure applied by the inner contact part (110) to the surface of the tree is maintained constant within a set range.

[0188] Additionally, in step S120, the movement range and movement resistance of the outer sliding part (120) can be set together.

[0189] For example, the sliding guide structure may further include a stopper, a friction control part, or a damping element so that sudden movement or vibrating movement of the outer sliding part (120) can be suppressed.

[0190] Through this, the outer sliding part (120) smoothly responds to long-term displacement due to the growth of roadside trees, while preventing unnecessary movement due to short-term disturbances.

[0191] In step S130, with the sliding coupling of the inner contact part (110), the outer sliding part (120), and the static load spring part (130) and the basic tension setting completed through step S120, the banner is fixed to the banner fastening part (140) to form a load transfer path between the street tree growth-responsive smart banner fixing device (100) and the banner.

[0192] The banner fastening part (140) is coupled to the outer sliding part (120) and is configured to secure the banner in a manner that does not grip or penetrate the upper or lower edge of the banner. The banner fastening part (140) can be implemented as a clamp type, hook type, sleeve type, or ring coupling type structure, and is designed so that the fastening force is evenly distributed according to the material and thickness of the banner. Accordingly, local tearing or wear of the banner is prevented, and a stable fastening state is maintained even under repeated load application.

[0193] During the banner fastening process, the edge of the banner is inserted into the banner fastening part (140) or hooked onto the hook, after which a fastening force is applied. At this time, the banner fastening part (140) is not directly rigidly coupled with the outer sliding part (120), but can be coupled via an elastic damper or a torque blocking connection part.

[0194] Accordingly, the tensile force acting on the banner is transmitted to the elastic damper through the fastening part (140) and is primarily absorbed and dampened, and the rotational torque component is prevented from being transmitted to the outer sliding part (120) by the torque blocking connection part.

[0195] When the banner is fixed to the fastening part (140), the self-weight and initial tension acting on the banner are transmitted to the static load spring part (130) through the outer sliding part (120). At this time, since the static load spring part (130) maintains a set basic tension, the contact pressure applied by the inner contact part (110) to the surface of the roadside tree is maintained within a certain range despite changes in the initial tensile force that occur when the banner is fastened. In other words, the phenomenon in which the roadside tree growth-responsive smart banner fixing device (100) is excessively tightened or loosened toward the roadside tree due to the fastening of the banner is suppressed.

[0196] In addition, the tension balance between the left and right sides of the banner is automatically corrected during the banner fastening process. When a relatively large tension is applied to one side of the banner, the outer sliding part (120) moves slightly under the constant tensile force condition of the constant load spring part (130) to absorb the tension difference, thereby forming uniform tension throughout the banner. Accordingly, asymmetric sagging or biased installation of the banner is prevented.

[0197] Optionally, in an embodiment in which a tension sensor is included in the banner fastening part (140), the tension sensor detects the tensile force of the banner simultaneously with the banner fastening and transmits the corresponding signal to the IoT control unit. The IoT control unit can store the tension value immediately after fastening as a reference value or use it to set an initial tension range indicating a normal installation state. Through this, subsequent changes in tension due to wind load or the elapsed installation period can be analyzed more accurately.

[0198] In step S140, as the growth of the street tree progresses over time, the increase in the outer diameter of the street tree is mechanically recognized by the street tree growth-responsive smart banner fixing device (100), and a process is performed in which a radial displacement occurs accordingly.

[0199] After the banner is secured, the smart banner fixing device (100) that responds to the growth of the street tree is installed on the street tree, and the diameter of the stem of the street tree gradually increases according to seasonal changes, water absorption, and the growth cycle. This hypertrophic growth is first reflected in the inner contact part (110) that is in close contact with the outer surface of the street tree, and the inner contact part (110) causes a minute radial displacement in the outward direction while maintaining contact with the surface of the street tree. At this time, the radial displacement does not occur instantaneously but appears in the form of low-speed displacement that accumulates over a long period.

[0200] Since the inner contact portion (110) functions as a reference support structure while maintaining contact with the outer surface of the tree, the contact force acting in the outer direction of the inner contact portion (110) changes as the diameter of the tree increases. This change in contact force is transmitted to the outer sliding portion (120) through a mechanical coupling relationship with the outer sliding portion (120), and the outer sliding portion (120) tends to move radially relative to the inner contact portion (110).

[0201] In this process, since the constant load spring part (130) provides a constant tensile force while connecting the inner contact part (110) and the outer sliding part (120), when a force is generated that causes the outer sliding part (120) to move outward due to the excessive growth of the roadside tree, the constant load spring part (130) allows such movement without increasing the magnitude of the tensile force.

[0202] As a result, the outer sliding part (120) moves outward gradually in response to the increase in diameter of the street tree, and the outer diameter of the street tree growth-responsive smart banner fixing device (100) automatically expands.

[0203] At this time, the radial displacement is induced along the sliding guide structure of the outer sliding part (120), so the outer sliding part (120) moves only in the radial direction without rotating or twisting. In addition, by means of the friction control part or limiting structure included in the sliding guide structure, the long-term displacement due to the hypertrophic growth of the roadside tree is smoothly responded to, while unnecessary movement of the outer sliding part (120) due to short-term disturbances caused by wind or vibration is suppressed.

[0204] In step S150, the radial displacement generated in step S140 due to the hypertrophic growth of the roadside tree is converted into actual movement of the outer sliding part (120), and an operation is performed in which the outer diameter of the device (100) is automatically expanded.

[0205] When radial displacement in the outward direction relative to the inner contact portion (110) accumulates due to the hypertrophic growth of the roadside tree, the outer sliding portion (120) moves outward along the sliding guide structure formed on the inner contact portion (110). At this time, the movement of the outer sliding portion (120) is naturally induced by the increase in the outer diameter of the roadside tree and is achieved through pure mechanical interaction without a separate driving source or power supply.

[0206] The outer sliding part (120) is allowed only to move in the radial direction due to its coupling relationship with the inner contact part (110), and circumferential rotation or axial movement is restricted. Accordingly, the outer sliding part (120) expands uniformly outward while maintaining a state aligned with the change in the outer shape of the tree. This structural constraint prevents the outer sliding part (120) from moving in a biased direction or twisting, thereby ensuring the overall stability of the device (100).

[0207] During the movement of the outer sliding part (120), the constant load spring part (130) continuously provides a constant tensile force while connecting the inner contact part (110) and the outer sliding part (120). Since the tensile force of the constant load spring part (130) does not increase even if the movement distance of the outer sliding part (120) increases, the contact pressure applied by the inner contact part (110) to the surface of the roadside tree remains constant within a set range even while the outer sliding part (120) moves outward. Accordingly, even if the amount of growth of the roadside tree accumulates, the phenomenon of the bark being excessively compressed or dug into does not occur.

[0208] Additionally, the movement speed of the outer sliding part (120) is limited to a low-speed movement corresponding to the growth rate of the tree. Rapid movement of the outer sliding part (120) is suppressed by a friction control part, a damping element, or a gradual movement structure included in the sliding guide structure, thereby preventing malfunction caused by external impact or instantaneous load changes. Conversely, for radial displacement accumulated over a long period, the outer sliding part (120) moves gradually, so that the outer diameter of the device (100) automatically expands in response to the increase in the diameter of the tree.

[0209] As the outer sliding part (120) performs automatic extension movement, the banner fastening part (140) also moves outward together, and the tension acting on the banner is maintained near a reference value set by the static load spring part (130). This simultaneously suppresses sagging of the banner and excessive increase in tensile force, thereby maintaining the stability of the banner installation state.

[0210] In step S160, the constant load spring part (130) operates so that the contact pressure applied to the surface of the tree and the tension acting on the banner are maintained at a constant level within a set range, even while the outer sliding part (120) is automatically extended and moved.

[0211] The constant load spring part (130) is designed to provide a constant tensile force regardless of the elongation amount of the spring while connected between the inner contact part (110) and the outer sliding part (120). Accordingly, even if the outer sliding part (120) moves outward in response to the hypertrophic growth of the roadside tree, the magnitude of the tensile force provided by the constant load spring part (130) does not increase or decrease and remains almost constant.

[0212] As the outer diameter of the tree increases, the outer sliding part (120) moves radially, and during this process, the static load spring part (130) gradually extends. However, unlike a general coil spring, the tensile force of the static load spring part (130) does not increase in proportion to the amount of extension; therefore, the pressure applied by the inner contact part (110) to the surface of the tree is maintained near a set reference pressure regardless of the tree's growth amount. As a result, the phenomenon of the tree bark tightening or digging is suppressed even when the banner is installed for a long period of time.

[0213] In addition, even when the tensile force changes due to the self-weight of the banner and external wind load transmitted through the banner fastening part (140), the static load spring part (130) absorbs the change in tension smoothly. That is, when the tensile force acting on the banner increases, the outer sliding part (120) moves slightly to cushion the increase in tension, and when the tensile force decreases, the banner tension is restored to a reference value by the constant restoring force of the static load spring part (130). Through this, the banner tension is maintained stably despite changes in the external environment.

[0214] This operation of the constant load spring part (130) serves to stabilize the force equilibrium relationship between the inner contact part (110) and the outer sliding part (120). That is, even if long-term radial displacement due to tree growth and short-term tension fluctuations due to wind load are transmitted along the same path, the constant load spring part (130) prevents excessive load from being transmitted to both the tree surface and the banner by limiting the magnitude of the tension to a constant level.

[0215] Additionally, the constant load spring (130) acts to maintain the structural stability of the device (100) while following the movement of the outer sliding part (120). For example, even after the outer sliding part (120) moves outward as it grows, the constant load spring (130) pulls the outer sliding part (120) toward the inner contact part (110) with a constant tensile force, thereby preventing the components of the device (100) from becoming loose or developing play.

[0216] In step S170, when a wind load is applied to the banner due to external wind, gusts, or changes in airflow, a tensile force damping and rotational torque blocking operation is performed to prevent the load from being directly transmitted to the device (100) and the roadside tree.

[0217] When wind acts upon a banner installed, a load in the tensile direction, along with vibration components due to shaking and asymmetric loads, is generated on the banner. These wind loads are transmitted to the device (100) through the banner fastening part (140), and the fastening part (140) has a structure in which it is not directly rigidly connected to the outer sliding part (120) but is connected via an elastic damper and a torque blocking connection part.

[0218] When a momentary increase in tensile force occurs in the banner due to wind load, the tensile force is preferentially transmitted to the elastic damper. The elastic damper absorbs and mitigates the peak value of the tensile force through viscoelastic deformation and internal damping characteristics, and reduces the rate of change in tensile force. Accordingly, the rapid increase in tension caused by gusts of wind or momentary impact loads is suppressed from being directly transmitted to the outer sliding part (120) and the static load spring part (130).

[0219] In addition, the rotational torque component generated by the shaking of the banner is separated and blocked by the torque-blocking connection. The torque-blocking connection is configured to limit the degree of rotational freedom or block the rotational load transmission path between the banner fastening part (140) and the outer sliding part (120), thereby preventing the torsion or asymmetrical vibration of the banner from being transmitted toward the tree. Accordingly, only a limited radial compressive force is mainly transmitted to the tree, and the accumulation of torsion or bending loads is suppressed.

[0220] When a wind load is continuously applied, the elastic damper gradually dissipates energy regarding repetitive tensile force fluctuations and suppresses resonance or vibration amplification phenomena. In this process, the static load spring part (130) accepts only the average tensile force component that has passed through the elastic damper and performs the role of maintaining the reference value of the tension. That is, the load of short-term, high-frequency components is absorbed by the elastic damper, and only the displacement of long-term, low-frequency components is transmitted to the outer sliding part (120) and the static load spring part (130).

[0221] As the tensile force damping and torque blocking operations are performed in this manner, even if a wind load occurs, the contact pressure applied by the inner contact part (110) to the surface of the roadside tree does not increase rapidly, and frictional damage or local pressure on the bark is prevented. In addition, the fastening state of the banner fastening part (140) is maintained stably, thereby reducing the risk of the banner falling off or being damaged.

[0222] In step S170, when a wind load is applied to the banner due to external wind, gusts, or turbulence caused by vehicle traffic, the path through which the load is transmitted to the device (100) and the roadside tree is controlled to attenuate the peak value of the tensile force and block the rotational torque component.

[0223] This step is a safety operation step to prevent sudden changes in pressure applied to the surface of trees in an environment where the banner is continuously shaking, and to maintain the fastening stability of the device (100).

[0224] When a wind load is applied to a banner, the banner is pushed or flutters in the direction of the wind, and the tension increases or decreases instantaneously. In particular, when asymmetric winds act on the left and right or up and down of the banner, not only tensile force but also rotational components in the twisting and yaw directions occur simultaneously. At this time, the load is concentrated at the edge of the banner, and the banner fastening part (140) receives the load first.

[0225] The banner fastening part (140) is not directly connected to the outer sliding part (120) as a rigid body, but rather has a structure connected via an elastic damper and a torque blocking connection part. Accordingly, the load transmitted to the fastening part (140) by wind load is separated into a tensile direction component and a rotational torque component and processed through different mechanisms.

[0226] That is, the tensile direction component is absorbed and damped through the elastic damper, and the rotational torque component is prevented from being transmitted in the direction of the outer sliding part (120) and the inner contact part (110) by the torque blocking connection part.

[0227] During the tensile force damping process, the elastic damper smoothly converts the rapid change in tension caused by wind load. When the tension suddenly increases due to gusts of wind, the elastic damper dissipates some of the peak energy into internal friction or deformation energy through elastic deformation and viscoelastic damping, thereby reducing the effective load transmitted to the outer sliding part (120).

[0228] In addition, even when the wind load fluctuates repeatedly, the elastic damper gradually dissipates vibration energy through hysteresis characteristics, thereby suppressing the occurrence of resonance or vibration amplification. Accordingly, the phenomenon in which the outer sliding part (120) and the static load spring part (130) are unnecessarily displaced significantly by short-term and high-frequency loads is reduced.

[0229] In the process of blocking rotational torque, the torque blocking connection prevents rotational loads caused by twisting or left-right shaking of the banner from being transmitted to the roadside tree through the device (100).

[0230] For example, if the torque-blocking connection is implemented as a pin coupling structure, a flexible link structure, or a directional rotation limiting structure that partially allows rotational freedom, the rotational component generated in the banner fastening part (140) is eliminated by free rotation or deformation within the connection part, and mainly only a load in the tensile direction is transmitted to the outer sliding part (120). This prevents the repeated accumulation of torsional stress on the tree trunk.

[0231] The average load component passing through the elastic damper and torque blocking connection is transmitted to the outer sliding part (120), and the outer sliding part (120) maintains force equilibrium with the constant load spring part (130) while the direction of movement is controlled by the sliding guide structure.

[0232] When the tension of the banner increases due to wind load, the outer sliding part (120) can absorb the change in tension through fine movement, but is limited so that the reference value of the tension does not rise rapidly due to the constant tensile force characteristic of the constant load spring part (130).

[0233] Conversely, when the wind load decreases and the tension is lowered, the outer sliding part (120) is corrected toward the reference position by the constant restoring force of the constant load spring part (130) so that the banner does not sag excessively.

[0234] As a result, the contact pressure applied by the inner contact portion (110) to the surface of the tree in a wind load environment does not increase rapidly due to the operation of step S170, and frictional damage to the bark or local pressure is suppressed.

[0235] In addition, the impact load at the banner fastening part (140) is reduced, thereby decreasing the possibility of damage to the banner, detachment of the fastening part, or abnormal displacement of the device (100). Furthermore, by blocking the rotational torque component, the torsional stress accumulated over a long period in the tree trunk is reduced, so the tree protection effect is maintained for a long period.

[0236] Optionally, in an embodiment where a tension sensor is placed in the banner fastening part (140), a tension fluctuation due to wind load is detected as a sensor signal, and the IoT control unit applies filtering to the signal to calculate an estimated tension value with instantaneous peaks due to gusts removed. At this time, since the elastic damper preemptively mitigates the load peaks, sensor saturation or excessive false detection is reduced, and the judgment logic based on the tension duration can be performed stably.

[0238] FIG. 4 is a flowchart illustrating an embodiment of a smart banner fixing device that responds to the growth of street trees according to the present invention.

[0239] Referring to FIG. 4, in step S210, the tensile force acting on the banner fastening part (140) is detected by a tension sensor and collected as basic data for determining the installation status of the banner, wind load influence, and safety status.

[0240] Step S210 is a step of quantitatively recognizing the load state generated by the mechanical operation of the device (100), and forms input data for time-based judgment and violation judgment performed in subsequent steps.

[0241] When tension is generated in the banner due to external wind, gravity, vibration, or environmental changes while the banner is fastened, the tension is transmitted to the tension sensor through the banner fastening part (140).

[0242] The tension sensor is positioned between the banner fastening part (140) and the outer sliding part (120), or inside the banner fastening part (140), and is configured to directly or indirectly detect the tensile load acting on the banner. Accordingly, the tensile force of the banner is converted into a micro-deformation, pressure change, or electrical characteristic change of the sensor structure.

[0243] In one embodiment, the tension sensor includes an elastic member to which a strain gauge is attached, and when a tensile force is applied to the banner fastening part (140), the elastic member is slightly deformed, and accordingly, the resistance value of the strain gauge changes.

[0244] This change in resistance is converted into a voltage signal through a bridge circuit and output, and the corresponding voltage signal is transmitted to the IoT control unit as an analog signal proportional to the magnitude of the tension. At this time, the tension sensor is positioned to have maximum sensitivity in the tension direction identical to the fastening direction, thereby minimizing the influence of rotational or shear components.

[0245] In another embodiment, the tension sensor may be implemented as a load cell and is inserted between the banner fastening part (140) and the outer sliding part (120) and positioned on the path through which the tensile load passes. In this case, the tensile force acting on the banner is directly transmitted to the sensor body, and the deformation element inside the sensor responds in proportion to the load. This structure is advantageous for measuring the absolute value of the tension and provides relatively high reliability even in long-term installation environments.

[0246] In another embodiment, the tension sensor may include a fiber-optic-based sensor or a piezoelectric element and may be configured to have high responsiveness to repetitive micro-vibrations or sudden changes in tension. This sensor method is advantageous for precisely detecting tension change patterns due to wind load and can be utilized for analyzing the swaying characteristics of a banner.

[0247] The sensor signal output from the tension sensor is a raw signal that may contain instantaneous fluctuations due to wind load, vibration components, and electrical noise. Therefore, the signal detected by the tension sensor is transmitted to the IoT control unit, where filtering and correction processing are performed in a subsequent stage. The key aspect of this stage is that the sensor does not merely determine the "presence or absence of tension," but continuously measures the magnitude and pattern of change of tension over time.

[0248] In addition, the tension sensor can be linked with the mechanical structure of the device (100) to more accurately reflect the tension state.

[0249] For example, even though the outer sliding part (120) maintains a constant tension condition by the constant load spring part (130), if the tension sensor detects a sudden increase in tension, this can be interpreted as an indicator of an increase in wind load or a fastening abnormality.

[0250] Conversely, if the tension sensor output remains constant even as the amount of movement of the outer sliding part (120) increases, it can be determined that the normal expansion state is due to the growth of the roadside tree.

[0251] The tension sensor can also perform self-diagnostic functions. For example, if the tension sensor's output remains at the same value for an extended period or exceeds the physically possible range, it may be determined to be in a disconnected, detached, or faulty state. This diagnostic information can be recorded via the IoT control unit or transmitted to a management server to be used for maintenance decisions.

[0252] In step S220, noise removal, correction, and stabilization processing are performed on the raw sensor signal detected by the tension sensor in step S210 to calculate an estimated tension value representing the tension actually acting on the banner.

[0253] Step S220 is a preprocessing step designed to prevent false detections caused by instantaneous fluctuations due to wind load or electrical noise, and to ensure the reliability of time-based judgments performed in subsequent steps.

[0254] The sensor signal output from the tension sensor may be in the form of an analog voltage, current, or digital signal, and may include vibration components due to wind load, spike signals caused by gusts, thermal noise of the sensor itself, and external electromagnetic interference components.

[0255] Accordingly, the IoT control unit performs amplification and offset correction on the input signal, and then applies filtering processing. During the amplification and correction process, the sensor's zero point error, sensitivity deviation, and initial deviation that may occur during device installation are corrected, and the sensor output is normalized so that it corresponds linearly to the tension value.

[0256] In the filtering process step, the IoT control unit applies a moving average filter, a low-pass filter, a median filter, or a combination thereof to remove high-frequency noise and transient peak components.

[0257] For example, if tension rises rapidly in a short period due to a gust of wind, the corresponding peak is smoothed out or removed during the filtering process so that the tension estimate does not overstate the actual structural load state. This filtering enables the identification of a stable trend in tension values ​​even in environments where the banner is continuously swaying.

[0258] Furthermore, the IoT control unit analyzes the rate of change of the tension signal to distinguish between short-term disturbances and long-term load changes. If the rate of change is rapid but the duration is short, it is determined to be a temporary fluctuation caused by external gusts and is reflected only restrictively in the tension estimate; however, if the rate of change is gradual and sustained for a long period, it is determined to be an actual increase in tension and is reflected in the tension estimate. This reduces the possibility of false alarms caused by changes in the wind environment.

[0259] Once the filtering and correction processing is complete, the IoT control unit calculates the tension estimate at that point in time. The tension estimate is calculated by applying a sensor sensitivity coefficient and a correction coefficient to the filtered sensor signal, and is defined as a value representing the magnitude of the tensile force acting on the banner fastening part. This tension estimate can be stored as a single point in time value or accumulated in chronological order to be managed as tension change history data.

[0260] In the process of calculating the tension estimate, information regarding the interaction with the device's mechanical structure can be taken into account. For example, if the tension estimate remains constant while the movement of the outer sliding part increases, this can be interpreted as a normal expansion state resulting from the hypertrophic growth of roadside trees. Conversely, if the tension estimate continuously increases despite almost no change in the movement of the outer sliding part, this can be determined as an increase in wind load or a fastening abnormality. This interconnected analysis improves reliability compared to judgments relying solely on sensor values.

[0261] In addition, the IoT control unit may perform upper and lower limit checks to verify the validity of the tension estimate. If the tension estimate falls outside the physically possible range, it is determined to be a sensor malfunction or an installation error, and the value may be invalidated or classified as a separate diagnostic event.

[0262] In step S230, the tension duration is calculated by utilizing the tension estimate derived in step S220 to quantify how long the state in which the tension is maintained above a preset tension threshold is sustained. Unlike a method that simply determines the presence of risk based on the magnitude of the tension at a specific point in time, this step uses the “duration” of the tension as a judgment criterion; this suppresses false alarms caused by gusts of wind or instantaneous vibrations and enables the stable determination of installations exceeding the permitted period or hazardous conditions.

[0263] The IoT control unit receives tension estimates updated along the time axis as input and determines at each measurement point whether the value exceeds a tension threshold. This determination result is converted into a state variable classified into 'excessive state' and 'non-excessive state,' and the IoT control unit calculates the accumulated time during the interval in which the excess state is maintained as the tension duration. In other words, the tension duration is defined as the "length of the time interval during which the tension is above the reference," and the key subject of judgment is a continuous time interval rather than a momentary peak of tension.

[0264] In the process of calculating the tension duration, the IoT control unit can stabilize the state transition conditions to prevent the over / non-over state from frequently toggling even when the tension estimate value fluctuates slightly near the threshold.

[0265] For example, if minor vibrations occur where the tension estimate slightly exceeds or falls below a threshold, the IoT control unit applies a hysteresis threshold and sets the upper and lower thresholds differently to prevent excessive state transitions.

[0266] In addition, by applying a minimum duration condition, the system can be configured to confirm the state as exceeding the threshold only if the state is maintained for a certain period of time or longer. This further suppresses false detections caused by subtle wind vibrations or sensor noise.

[0267] The calculation of tension duration can be implemented using either a continuous-time or discrete-time method. In the discrete-time method, the IoT controller determines whether the tension estimate, updated at each measurement cycle, exceeds a threshold value; if the condition is true, the measurement cycle is added to the accumulated tension duration. If the condition is false, accumulation can be stopped, or the accumulated value can be reset if necessary. Accordingly, the tension duration is calculated by accumulating it in units of measurement cycles, making it easy to calculate the total time the tension state is maintained above a certain standard.

[0268] In addition, the IoT control unit can calculate the tension duration based on multiple time windows, rather than managing it as a single cumulative value. For example, a short duration for short-term risk assessment and a long duration for permit period exceeding assessment can be calculated separately and provided to judgment logic for different purposes.

[0269] Short-term duration can be used to detect hazardous conditions requiring immediate response, such as strong winds or abnormal fastening, and long-term duration can be used to estimate the state in which banners remain installed even after the permit period has expired.

[0270] The results of the tension duration calculation are compared with the permit period information or the risk threshold time in a subsequent stage to determine whether a violation has occurred or if a risk condition exists. For example, if the tension duration exceeds the pre-set risk threshold time, it may be determined to be a risk condition; and if the tension duration continues to accumulate even after the permit period has expired, it may be determined to be an installation exceeding the permit period.

[0271] In this case, since the tension duration serves as a key indicator of the actual installation status of the banner, the IoT control unit can be configured to store tension duration data in memory or report it to a management server at regular intervals.

[0272] In step S240, the IoT control unit obtains information regarding the permit period for banner installation and determines compliance or violation of the permit period by comparing it with the current time and the tension duration. This step is a key step that goes beyond simple tension monitoring and enables the efficient management of unauthorized or long-term abandoned banners by implementing the administrative rule of "permission period" into an automatic judgment logic.

[0273] The IoT control unit loads permission period information corresponding to the device identification information. The permission period information can be expressed as the start time, end time, or number of days of permission for banner installation, and can be stored in a pre-registered form in the internal storage of the IoT control unit or downloaded and stored from the management server.

[0274] For example, when an installer registers a device identifier and an authorization period via a terminal at the time of on-site installation, the management server generates authorization period data for the device and transmits it to the IoT control unit, and the IoT control unit stores the received data in the storage unit.

[0275] In another embodiment, the IoT control unit may connect to a management server at boot times or at regular intervals to send a request including a device identifier and load permission period information provided in the response.

[0276] When the permission period information is loaded, the IoT control unit determines the reference time to be used for comparison judgment. The reference time can utilize the clock value within the IoT control unit or can utilize a time synchronized with the standard time of the management server.

[0277] When using an internal clock, time drift may occur due to long-term operation; therefore, the IoT control unit can correct errors by periodically performing time synchronization when server access is available. In environments where server access is difficult, a method may be applied in which the reference time entered at the time of installation is stored and the elapsed time is calculated based on this.

[0278] The IoT control unit calculates the permission expiration time from the loaded permission period information. If the permission end time is provided directly, that time is set as the expiration time; if only the number of permission days is provided, the permission expiration time is calculated by adding the number of permission days to the installation registration time.

[0279] In addition, to prepare for cases where the permission period is changed or extended, the IoT control unit stores the version, update time, or validity period of the permission period information together, and when update data is received from the server, it can replace the existing information or maintain it in parallel.

[0280] Once the permission expiration time is determined, the IoT control unit compares the current time with the permission expiration time to determine whether the permission period has elapsed. If the permission period is still valid, it is classified as "within permission period," and if the current time exceeds the permission expiration time, it is classified as "permission period exceeded."

[0281] In this case, the IoT control unit can determine whether to maintain the actual installation by combining it with the result of calculating the tension duration, rather than relying solely on the expiration time.

[0282] For example, even if the permit period has been exceeded, if the estimated tension value remains below the tension threshold and the duration of tension does not accumulate, the banner may be deemed to have been removed and not treated as a violation.

[0283] Conversely, if the duration of tension continues to increase even after the permitted period has expired, it can be determined that the banner remains installed and confirmed as a violation.

[0284] In addition, the IoT control unit can compare the tension duration and the risk threshold time to determine safety risks not only when the permit period has been exceeded, but also within the permit period. For example, if the estimated tension value remains above a risk threshold for a certain period, or if the tension duration exceeds a preset risk threshold time, it can be determined as a "dangerous state" and processed as an alarm condition regardless of the permit period. This is intended to detect early situations where the risk of falling or fastening detachment increases during strong winds.

[0285] To handle cases where permission period information is not loaded or is incomplete, the IoT control unit may include additional exception handling logic. For example, if permission period information does not exist or is entered in an invalid format, the IoT control unit may classify it as "permission information not registered" and send a registration request or inspection notification to the management server.

[0286] In addition, even if permission period renewal information is not received due to a communication failure, the IoT control unit performs a provisional judgment based on the last confirmed permission period information and can correct the judgment result by synchronizing with the server upon communication recovery.

[0287] Consequently, through step S240, the IoT control unit reliably secures and updates permit period information and reliably determines compliance or violation of the permit period by comparing it with the current time and the tension duration. This allows banner management tasks to transition from a human-based inspection model to an automated judgment model, thereby substantially realizing the active monitoring function of the present invention.

[0288] In step S250, based on the comparison result of the tension duration calculated in step S230 and the permit period determined in step S240, a final determination is made as to whether the banner installation status violates the pre-set management standards; if it is determined to be in violation, a violation event is generated and an alert is transmitted to the managing entity. This step is an execution step in which the smart management function according to the present invention is connected to actual administrative enforcement and maintenance.

[0289] The IoT control unit determines a violation condition when the permit period has been exceeded and the tension duration is maintained above the tension threshold. In other words, rather than relying solely on whether the permit has expired, a violation is confirmed only when it is verified via tension that the banner remains actually installed even after the expiration. This prevents false positives regarding banners that have already been removed after the permit expired or conditions where tension is temporarily absent.

[0290] In addition, the IoT control unit may determine a separate safety violation state if the estimated tension value remains above a risk threshold for a certain period of time, even within the permit period. For example, if excessive tensile force is maintained on a banner for a long time due to strong winds, fastening defects, or structural damage, this is determined to be a state where there is a risk of falling or damage to roadside trees, thereby immediately satisfying the conditions for generating a violation event. In this way, multiple types of violations can be defined in this stage by distinguishing between permit violations and safety violations.

[0291] When violation conditions are met, the IoT control unit creates a violation event object. The violation event object includes device identification information, street tree installation location information, violation type, time of violation occurrence, estimated tension value, tension duration, permit expiration time, and current status code. This event information is generated in a structured form so that it can be utilized as supporting data for recording, statistical analysis, and administrative actions on the management server.

[0292] When a violation event object is created, the IoT control unit transmits the event to the management server. Transmission is performed via a wireless communication module, and at least one of cellular communication, low-power wide-area communication, or short-range wireless communication may be applied. To prepare for cases where the communication environment is unstable, the IoT control unit may be configured to temporarily store the violation event in an internal storage unit and retransmit it without omission when communication is restored.

[0293] The management server generates an alert message based on received violation events and delivers the alert to pre-configured recipients. The alert recipients may be set to at least one of local government officials, banner management companies, maintenance personnel, or enforcement agencies. The alert delivery method may include at least one of web-based monitoring screen notifications, mobile application push notifications, text messages, or email.

[0294] In addition, the management server can accumulate and manage violation events occurring repeatedly on the same device or at the same location, and raise the alert level based on the frequency of violations. For example, a caution notification is sent upon a single violation, and if repeated violations occur within a certain period, it can be progressively raised to a warning or an emergency action notification. This grading can be utilized to determine the priority of administrative measures.

[0295] Meanwhile, the IoT control unit continues to monitor the tension status even after a violation event is generated. If the estimated tension value decreases below a threshold or the duration of tension no longer accumulates, it can be determined that the banner has been removed or the danger status has been resolved. In this case, the IoT control unit may additionally generate a violation release event or a status change event and send it to the management server, through which the management server can automatically update the status of banner removal completion or action completion. Explanation of the symbols

[0297] 100: Street tree growth-responsive smart banner fixing device, 110: Inner contact portion, 120: Outer sliding part, 130: Static load spring section, 140: Banner fastening part, 150: Elastic damper, 160: Torque cutoff connection,

Claims

Claim 1 A smart banner fixing device for responding to the growth of a street tree, comprising: an inner contact part positioned to contact the outer surface of the street tree and adhering to the surface of the street tree; an outer sliding part positioned on the outer side of the inner contact part and coupled to allow relative movement in the radial direction according to the hypertrophic growth of the street tree; a constant load spring part connected between the inner contact part and the outer sliding part and configured to provide a constant tensile force regardless of the movement distance of the outer sliding part; and a banner fastening part coupled to the outer sliding part to fix the banner. Claim 2 A smart banner fixing device that responds to street tree growth, characterized in that, in claim 1, the inner contact portion comprises a plurality of curved plates having a curvature corresponding to the outer circumference shape of the street tree, and the street tree contact surface of the curved plates is formed of an elastic material. Claim 3 A smart banner fixing device for street tree growth, characterized in that, in claim 1, the outer sliding part is movably coupled along a sliding guide structure formed in the inner contact part. Claim 4 A smart banner fixing device for street tree growth, characterized in that, in claim 1, the outer sliding part includes a strip-type static load spring that provides a constant tensile force regardless of the elongation amount of the spring. Claim 5 A smart banner fixing device for responding to street tree growth according to claim 1, characterized in that the banner fastening part is coupled to the outer sliding part via an elastic damper and a torque-blocking connection part, so as to dampen the tensile force caused by wind load and block the transmission of rotational torque. Claim 6 A method for fixing a banner using a smart banner fixing device that responds to the growth of a street tree, comprising: a step of closely positioning an inner contact portion on the outer surface of a street tree; a step of connecting an outer sliding portion to the outer side of the inner contact portion so as to be movably relative in the radial direction; a step of connecting a constant load spring portion between the inner contact portion and the outer sliding portion to provide a constant tensile force regardless of the movement distance of the outer sliding portion; a step of fixing a banner by connecting a banner fastening portion to the outer sliding portion; and a step of ensuring that the contact pressure applied to the surface of the street tree by the constant load spring portion is maintained constant while the outer sliding portion automatically moves in the radial direction according to the hypertrophic growth of the street tree. Claim 7 A method for fixing a smart banner that responds to the growth of a street tree, characterized in that, in claim 6, the step of closely positioning an inner contact portion on the outer surface of the street tree includes the step of arranging a plurality of curved plates having a curvature corresponding to the shape of the outer surface of the street tree in the direction of the circumference of the street tree, and dispersing contact pressure through an elastic material formed on the contact surface of the curved plates with the street tree. Claim 8 A method for fixing a smart banner that responds to street tree growth, characterized in that, in claim 6, the step of coupling an outer sliding part to the outer side of the inner contact part so as to be movable in a radial direction relative to the outer sliding part includes the step of coupling the outer sliding part so as to be movable only in a radial direction along a sliding guide structure formed in the inner contact part. Claim 9 A method for fixing a smart banner that responds to the growth of a roadside tree, characterized in that, in claim 6, the step of connecting a constant load spring member between the inner contact member and the outer sliding member to provide a constant tensile force regardless of the movement distance of the outer sliding member includes the step of using a strip-type constant load spring that provides a constant tensile force regardless of the elongation amount of the spring, thereby maintaining a constant contact pressure applied to the surface of the roadside tree as the outer sliding member moves. Claim 10 In claim 6, the step of fixing the banner by connecting the banner fastening part to the outer sliding part comprises connecting the banner fastening part to the outer sliding part via an elastic damper and a torque blocking connection part, thereby dampening the tensile force generated by wind load and blocking the transmission of rotational torque generated by the shaking of the banner toward the roadside tree, characterized in that it is a smart banner fixing method responsive to roadside tree growth.

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