Mounting jig

CN224889880UActive Publication Date: 2026-10-23SHENZHEN HANYANG TECHNOLOGY CO LTD
View PDF 0 Cites 0 Cited by

Patent Information

Application Number
CN202522314126.2
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2025-10-31
Publication Date
2026-10-23
Estimated Expiration
2035-10-31

AI Technical Summary

Technical Problem

天线组件的结构多为圆柱或近圆柱特征,连接固定常采用螺纹紧固或螺钉锁付;在锁付阶段易出现整体随动旋转,定位基准滑移,导致装配角度偏差与回装返修

Benefits of technology

[0015]在本技术方案中,延伸支架由两部分结构连接而成,且延伸支架的端部形成有凸台,连接件套设于延伸支架远离凸台的一端,并采用螺丝穿设于连接件和延伸支架即可完成天线组件的组装;底板上形成有用于与所述凸台固定的安装台,安装台的设计确保了凸台能够稳固地固定在底板上,从而为天线组件提供了稳定的支撑;两个侧板滑动设于底板,并位于安装台相对的两侧,两个侧板能够相互靠近或远离,以包覆所述延伸支架、所述凸台以及所述连接件的部分结构的外周壁,这种设计使得侧板可以根据天线组件的具体尺寸进行调整,确保包覆的紧密性和适应性;连接件的另一部分结构显露于两个侧板之间,采用螺丝即可将连接件与延伸支架紧固连接,完成天线组件的安装。在装配过程中,先将两部分结构组成的延伸支架连接,同时将凸台放置在底板的安装台上,确保凸台与安装台紧密配合,实现稳固固定,再将连接件套设于延伸支架远离凸台的一端,将两个侧板滑动至底板上,使两个侧板相互靠近,包覆延伸支架、凸台以及连接件的部分结构的外周壁,再采用螺丝穿设于连接件和延伸支架远离凸台的一端,以完成天线组件的装配,侧板的滑动设计使得包覆过程简单快捷,采用该安装治具能够大大提高天线组件的装配效率。

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN224889880U_ABST
    Figure CN224889880U_ABST
Patent Text Reader

Abstract

The utility model discloses a kind of installation jigs, it is related to installation jig technical field, wherein, installation jig is used to install antenna assembly, the antenna assembly has sequentially connected connecting piece, extension support and boss, the installation jig includes bottom plate and two side plates, the bottom plate is formed with the installation platform for with the boss fixed;Two the side plate slidingly set in the bottom plate, and located the two sides opposite of the installation platform, two the side plate can be mutually close or far away, to coat the outer peripheral wall of the part structure of the extension support, the boss and the connecting piece, another part structure of the connecting piece is exposed to two the side plate.The technical scheme provided by the utility model aims at effectively protecting antenna assembly from being damaged by external force during assembly process, while improving assembly efficiency and quality.
Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] This utility model relates to the field of installation fixture technology, and in particular to an installation fixture. Background Technology

[0002] During the operation of self-moving devices (such as intelligent mobile devices used for snow removal, lawn mowing, and leaf blowing), communication with a remote control platform or cloud is achieved through an antenna assembly to complete key functions such as positioning and data transmission. The antenna assembly not only needs to remain stable in complex working environments but also needs sufficient flexibility to adapt to different operating scenarios. To improve the reliability of self-moving devices in confined spaces, complex work sites, and low-obstacle environments, our company has designed an antenna assembly including an radome, an extension bracket, and a connecting component. The extension bracket has a lower rigidity than the radome, allowing it to absorb energy through controlled deformation when subjected to external impacts, reducing the risk of damage to the antenna body and device housing.

[0003] Several unresolved issues remain during mass production assembly. Antenna assemblies are mostly cylindrical or near-cylindrical in structure, and connections are typically secured using threaded fasteners or screws. During the fastening stage, overall rotation and slippage of the positioning reference can easily occur, leading to assembly angle deviations and reassembly repairs. The extension bracket is made of a relatively low-hardness material, and the stress path during assembly is concentrated at the base of the bracket and the interface area with the housing. Local buckling, micro-cracks, and permanent deformation can easily occur during top pressing, wire lead-out, and radome placement, affecting communication performance and consistency. Furthermore, the lack of stable support and restraint around the cable exit holes means that when cables are pulled or twisted, additional loads are transmitted to the bracket, further amplifying the aforementioned failure risks.

[0004] To address pain points such as preventing rotation of cylindrical parts, force misalignment of weakly supported components, and insufficient assembly efficiency, there is an urgent need for matching installation fixtures. These fixtures should enable multi-point positioning, force diversion, and rapid alignment of bosses, extension brackets, and connectors, while also providing positioning and protection while routing cables through through holes. This will improve production line assembly efficiency and product durability. Utility Model Content

[0005] The main purpose of this utility model is to provide an installation fixture that effectively protects the antenna assembly from external damage during assembly, while improving assembly efficiency and quality.

[0006] To achieve the above objectives, the present invention proposes a mounting fixture for mounting an antenna assembly. The antenna assembly has a connector, an extension bracket, and a boss connected in sequence. The mounting fixture includes: A base plate having a mounting platform for fixing to the boss; Two side plates are slidably disposed on the base plate and located on opposite sides of the mounting platform. The two side plates can move closer to or further away from each other to cover the outer peripheral wall of the extension bracket, the boss, and part of the structure of the connector. Another part of the structure of the connector is exposed on the two side plates.

[0007] In one embodiment, the boss is provided with a plurality of positioning holes spaced apart along its circumference, and the mounting platform is provided with a plurality of limiting posts spaced apart along its circumference, each of the limiting posts being inserted into a positioning hole.

[0008] In one embodiment, the base plate has two mating portions spaced apart, and each side plate has two sliding portions at one end near the base plate, with each sliding portion slidingly engaging with one of the mating portions.

[0009] In one embodiment, the sliding part is one of a T-shaped groove and a T-shaped slider, and the mating part is the other of a T-shaped groove and a T-shaped slider.

[0010] In one embodiment, each of the side plates has a connecting protrusion on the side opposite to the other side plate, and the connecting protrusion and the mating portion are both formed on the side of the side plate near the bottom plate.

[0011] In one embodiment, each of the side plates has a semi-annular groove on the side facing the other side plate, and the two semi-annular grooves enclose each other to form a receiving groove. The inner peripheral wall of the receiving groove is adapted to the outer peripheral wall of the extension bracket, the boss and part of the connecting member. Another part of the connecting member is exposed at the opening of the receiving groove.

[0012] In one embodiment, a first annular limiting step is formed at the connection between the connector and the extension bracket, a second annular limiting step is formed at the connection between the boss and the extension bracket, and a third and a fourth annular limiting step are formed at intervals on the inner peripheral wall of the receiving groove. The third annular limiting step abuts against and limits the first annular limiting step, and the fourth annular limiting step abuts against and limits the second annular limiting step.

[0013] In one embodiment, the mounting platform has a wire passage hole communicating with the receiving groove.

[0014] In one embodiment, the hardness of both side plates and the hardness of the base plate are both greater than the hardness of the extension bracket.

[0015] In this technical solution, the extension bracket is composed of two connected structures, and a boss is formed at the end of the extension bracket. The connector is fitted onto the end of the extension bracket away from the boss, and the antenna assembly is assembled by screwing through the connector and the extension bracket. A mounting platform is formed on the base plate for fixing the boss. The design of the mounting platform ensures that the boss can be firmly fixed on the base plate, thereby providing stable support for the antenna assembly. Two side plates are slidably disposed on the base plate and located on opposite sides of the mounting platform. The two side plates can move closer or further apart to cover the outer peripheral walls of the extension bracket, the boss, and part of the connector. This design allows the side plates to be adjusted according to the specific size of the antenna assembly, ensuring tightness and adaptability of the coverage. The other part of the connector is exposed between the two side plates. The connector is fastened to the extension bracket by screws to complete the installation of the antenna assembly. During assembly, the two-part extended bracket is first connected, and the boss is placed on the mounting platform of the base plate to ensure a tight fit between the boss and the mounting platform for stable fixation. Then, the connector is fitted onto the end of the extended bracket away from the boss, and the two side plates are slid onto the base plate so that they come close to each other, covering the outer perimeter of the extended bracket, boss, and connector. Finally, screws are inserted into the connector and the end of the extended bracket away from the boss to complete the assembly of the antenna assembly. The sliding design of the side plates makes the covering process simple and quick. Using this mounting fixture can greatly improve the assembly efficiency of the antenna assembly. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram of an embodiment of the mounting fixture provided by this utility model; Figure 2 A schematic diagram illustrating an embodiment of the present invention showing the installation of an mounting fixture and an antenna assembly. Figure 3 An exploded structural diagram illustrating an embodiment of the installation fixture and antenna assembly for the present invention. Figure 4 A cross-sectional view of an embodiment of the mounting fixture provided by this utility model.

[0018] Explanation of icon numbers: 100. Installation fixture; 1. Base plate; 11. Mounting platform; 12. Limiting post; 13. Mating part; 14. Wire hole; 2. Side plate; 21. Sliding part; 22. Connecting protrusion; 23. Semi-annular groove; 24. Receiving groove; 25. Third annular limiting step; 26. Fourth annular limiting step; 200. Antenna assembly; 210. Connector; 220. Boss; 221. Positioning hole; 230. Extension bracket.

[0019] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0021] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0023] This utility model proposes an installation fixture 100.

[0024] Please see Figure 2 and Figure 3In one embodiment of the present invention, the mounting fixture 100 is used to mount the antenna assembly 200. The antenna assembly 200 has a connector 210, an extension bracket 230 and a boss 220 connected in sequence. The mounting fixture 100 includes a base plate 1 and two side plates 2. The base plate 1 is formed with a mounting platform 11 for fixing to the boss 220. The two side plates 2 are slidably disposed on the base plate 1 and located on opposite sides of the mounting platform 11. The two side plates 2 can move closer to or further away from each other to cover the outer peripheral wall of part of the structure of the extension bracket 230, the boss 220 and the connector 210. Another part of the structure of the connector 210 is exposed on the two side plates 2.

[0025] In this technical solution, the extension bracket 230 is composed of two connected structures, and a boss 220 is formed at the end of the extension bracket 230. The connector 210 is sleeved on the end of the extension bracket 230 away from the boss 220, and the antenna assembly 200 can be assembled by screwing through the connector 210 and the extension bracket 230. A mounting platform 11 for fixing the boss 220 is formed on the base plate 1. The design of the mounting platform 11 ensures that the boss 220 can be firmly fixed on the base plate 1, thereby providing stable support for the antenna assembly 200. Two side plates 2 are slidably mounted on the base plate 1 and located on opposite sides of the mounting platform 11. The two side plates 2 can move closer or further apart to cover the outer peripheral walls of the extension bracket 230, the boss 220, and the connector 210. This design allows the side plates 2 to be adjusted according to the specific dimensions of the antenna assembly 200, ensuring tightness and adaptability of the covering. Another part of the connector 210 is exposed between the two side plates 2. The connector 210 can be fastened to the extension bracket 230 with screws to complete the installation of the antenna assembly 200. During the assembly process, the two-part extension bracket 230 is first connected, and the boss 220 is placed on the mounting platform 11 of the base plate 1 to ensure that the boss 220 and the mounting platform 11 fit tightly and are firmly fixed. Then, the connector 210 is fitted onto the end of the extension bracket 230 away from the boss 220. The two side plates 2 are slid onto the base plate 1 so that the two side plates 2 are close to each other and cover the outer peripheral wall of part of the structure of the extension bracket 230, the boss 220 and the connector 210. Then, screws are inserted into the connector 210 and the end of the extension bracket 230 away from the boss 220 to complete the assembly of the antenna assembly 200. The sliding design of the side plates 2 makes the covering process simple and quick. Using this mounting fixture 100 can greatly improve the assembly efficiency of the antenna assembly 200.

[0026] For better securing of antenna assembly 200, please refer to [link / reference]. Figure 3In one embodiment, the boss 220 has a plurality of positioning holes 221 spaced apart along its circumference, and the mounting platform 11 has a plurality of limiting posts 12 spaced apart along its circumference, each limiting post 12 being inserted into a positioning hole 221. When the boss 220 of the antenna assembly 200 is placed on the mounting platform 11 of the base plate 1, the plurality of positioning holes 221 on the boss 220 are aligned with the plurality of limiting posts 12 on the mounting platform 11, and each limiting post 12 is inserted into the corresponding positioning hole 221, ensuring the precise alignment and fixation of the boss 220 and the mounting platform 11, and also preventing the antenna assembly 200 from rotating, thereby improving the stability and reliability of the antenna assembly 200 installation. The precise alignment of the boss 220 with the mounting platform 11 is ensured by the cooperation of the positioning hole 221 and the limiting post 12. This precise alignment effectively prevents the antenna assembly 200 from shifting during assembly, improving the accuracy and stability of the assembly. The cooperation between the limiting post 12 and the positioning hole 221 not only ensures the precise alignment of the boss 220 with the mounting platform 11 but also provides additional fixing force, making the antenna assembly 200 more stable after assembly. This stable fixing effectively prevents the antenna assembly 200 from loosening due to vibration or external forces during operation, improving the reliability and service life of the antenna assembly 200. Through the cooperation of the positioning hole 221 and the limiting post 12, assembly personnel can quickly fix the boss 220 to the mounting platform 11 without additional alignment tools or complex adjustment steps. This not only improves assembly efficiency but also reduces potential errors during assembly, increasing overall production efficiency.

[0027] Specifically, please refer to Figure 3 In one embodiment, the base plate 1 has two mating portions 13 spaced apart, and each side plate 2 has two sliding portions 21 near the end of the base plate 1. Each sliding portion 21 is slidably engaged with a mating portion 13. The base plate 1 has two mating portions 13 spaced apart, which are used to slide and engage with the sliding portions 21 of the side plate 2 to ensure that the side plate 2 can slide smoothly and be fixed on the base plate 1, and to ensure that the side plate 2 will move along a set sliding stroke. The mating portions 13 and the sliding portions 21 can be dovetail grooves and dovetail blocks, or guide rails and sliders, respectively. This solution does not limit this. Through the sliding engagement of the mating portions 13 of the base plate 1 and the sliding portions 21 of the side plate 2, the side plate 2 can slide smoothly and be fixed on the base plate 1, improving the stability and reliability of the assembly. The sliding design of the side plate 2 makes the covering process simple and quick, omitting the process of separate assembly fixtures, and greatly improving the assembly efficiency.

[0028] For more details, please refer to Figure 3In one embodiment, the sliding part 21 is one of a T-shaped groove and a T-shaped slider, and the mating part 13 is the other of a T-shaped groove and a T-shaped slider. When the two mating parts 13 of the base plate 1 are T-shaped grooves, the sliding part 21 of the side plate 2 is a T-shaped slider, and the T-shaped groove and the T-shaped slider are in sliding engagement; when the two mating parts 13 of the base plate 1 are T-shaped sliders, the sliding part 21 of the side plate 2 is a T-shaped groove, and the T-shaped groove and the T-shaped slider are in sliding engagement; the design of the T-shaped groove and the T-shaped slider allows the side plate 2 to slide smoothly and be fixed to the base plate 1 when needed, ensuring the tightness and adaptability of the covering.

[0029] Please see Figure 3 In one embodiment, a connecting protrusion 22 is formed on the side of each side plate 2 away from the other side plate 2, and a mating part 13 is formed on the side of the connecting protrusion 22 and the side plate 2 near the bottom plate 1. The connecting protrusion 22 widens the width of the sliding connection between the side plate 2 and the base plate 1. By increasing the connecting protrusion 22, the contact area between the side plate 2 and the base plate 1 is increased, thereby enhancing the structural strength of the sliding connection. This design can effectively prevent the side plate 2 from deforming or being damaged by external forces during sliding, improving the overall stability and reliability. Both the connecting protrusion 22 and the side plate 2 near the base plate 1 have mating parts 13. The addition of the connecting protrusion 22 makes the side plate 2 more stable during sliding, reducing the shaking and displacement of the side plate 2. This design can effectively prevent the antenna assembly 200 from loosening or being damaged due to the instability of the side plate 2 during assembly, improving the stability of the antenna assembly 200. The connecting protrusion 22 widens the width of the sliding connection between the side plate 2 and the base plate 1. The addition of the connecting protrusion 22 can effectively disperse external forces and reduce the force on a single connection point, thereby enhancing the overall impact resistance of the fixture. This design can effectively prevent the antenna assembly 200 from being damaged by collisions during assembly, improving the service life of the antenna assembly 200.

[0030] Please see Figure 1 and Figure 3In one embodiment, each side plate 2 has a semi-annular groove 23 on the side facing the other side plate 2. The two semi-annular grooves 23 enclose to form a receiving groove 24. The inner peripheral wall of the receiving groove 24 is adapted to the outer peripheral wall of part of the extension bracket 230, boss 220, and connector 210. Another part of the connector 210 is exposed at the opening of the receiving groove 24. Through the precise adaptation of the inner peripheral wall of the receiving groove 24 to the outer peripheral wall of the extension bracket 230, boss 220, and connector 210, it can be ensured that these components are precisely covered and fixed during assembly. This design can effectively prevent the components from shifting or loosening during assembly, improving the accuracy and stability of assembly. Through precise covering, the receiving groove 24 can provide additional protection for the antenna assembly 200, reducing damage to the antenna assembly 200 caused by collision or vibration during assembly, thereby improving the service life and reliability of the antenna assembly 200. During actual assembly, the boss 220 is fixed to the mounting platform 11, and the two side plates 2 move closer to each other. The semi-annular groove 23 of each side plate 2 covers the outer peripheral wall of part of the structure of the extension bracket 230, the boss 220 and the connector 210, and forms a receiving groove 24 for the antenna assembly 200, which plays a protective role for the antenna assembly 200.

[0031] Please see Figure 4 In one embodiment, a first annular limiting step is formed at the connection between the connector 210 and the extension bracket 230, a second annular limiting step is formed at the connection between the boss 220 and the extension bracket 230, and a third annular limiting step 25 and a fourth annular limiting step 26 are formed at intervals on the inner peripheral wall of the accommodating groove 24. The third annular limiting step 25 abuts against the first annular limiting step and the fourth annular limiting step 26 abuts against the second annular limiting step. The interlocking ring-shaped limiting steps allow for precise positioning of each component of the antenna assembly 200. This design effectively prevents axial or radial movement of components during assembly, ensuring that the relative positions of each component are fixed after assembly, thus improving assembly accuracy and stability. The interlocking ring-shaped limiting steps also provide additional structural support, enhancing overall stability. This design effectively prevents the antenna assembly 200 from loosening or being damaged due to vibration or external forces during operation, improving its reliability and service life. Furthermore, the interlocking ring-shaped limiting steps allow assembly personnel to quickly install each component of the antenna assembly 200 into place without additional fixing tools or complex adjustment steps. This not only improves assembly efficiency but also reduces potential errors during assembly, thereby increasing overall production efficiency.

[0032] Please see Figure 3 and Figure 4The mounting platform 11 has a cable passage hole 14 that communicates with the receiving slot 24. The design of the cable passage hole 14 allows cables to directly enter the receiving slot 24 through the mounting platform 11, providing a clear path for the cables. Through the cable passage hole 14, cables can smoothly pass through the mounting platform 11 into the receiving slot 24 without the need for additional cable guiding devices or complex wiring steps. This not only improves assembly efficiency but also reduces potential errors during assembly, increasing overall production efficiency. Simultaneously, the design of the cable passage hole 14 ensures that the cables are not subjected to external forces during assembly, thereby reducing the pulling force of the cables on the antenna assembly 200 and enhancing the overall structural stability.

[0033] In one embodiment, the hardness of both side plates 2 and the hardness of the base plate 1 are greater than the hardness of the extension bracket 230. While the side plates 2 and the base plate 1 cover the antenna assembly 200, their hardness also needs to be greater than that of the extension bracket 230 to prevent damage to the side plates 2 and the base plate 1 upon impact, and to ensure that the antenna assembly 200 is not damaged. During assembly, the higher hardness of the side plates 2 and the base plate 1 allows them to better fix the extension bracket 230, ensuring the accuracy and stability of the assembly. Higher hardness also reduces deformation during assembly, thereby improving assembly precision and efficiency, and reducing the risk of damage to the antenna assembly 200 due to improper assembly.

[0034] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A mounting fixture for mounting an antenna assembly, the antenna assembly having a connector, an extension bracket, and a boss connected in sequence, characterized in that, include: A base plate having a mounting platform for fixing to the boss; Two side plates are slidably disposed on the base plate and located on opposite sides of the mounting platform. The two side plates can move closer to or further away from each other to cover the outer peripheral wall of the extension bracket, the boss, and part of the structure of the connector. Another part of the structure of the connector is exposed on the two side plates.

2. The mounting fixture as described in claim 1, wherein the boss is provided with a plurality of positioning holes spaced apart along its circumference, characterized in that: The mounting platform has multiple limiting posts spaced apart along its circumference, and each limiting post is inserted into a positioning hole.

3. The mounting fixture as described in claim 1, characterized in that: The base plate has two mating parts spaced apart, and each side plate has two sliding parts at one end near the base plate, with each sliding part slidingly engaging with one of the mating parts.

4. The mounting fixture as described in claim 3, characterized in that: The sliding part is one of a T-shaped groove and a T-shaped slider, and the mating part is the other of a T-shaped groove and a T-shaped slider.

5. The mounting fixture as described in claim 3, characterized in that: Each of the side plates has a connecting protrusion on the side opposite to the other side plate, and the connecting protrusion and the side plate near the bottom plate both have the mating part.

6. The mounting fixture as described in any one of claims 1 to 5, characterized in that: Each of the side plates has a semi-annular groove on the side facing the other side plate. The two semi-annular grooves enclose each other to form a receiving groove. The inner peripheral wall of the receiving groove is adapted to the outer peripheral wall of the extension bracket, the boss and part of the connecting member. Another part of the connecting member is exposed in the groove opening.

7. The mounting fixture as described in claim 6, wherein a first annular limiting step is formed at the connection between the connector and the extension bracket, and a second annular limiting step is formed at the connection between the boss and the extension bracket, characterized in that: The inner peripheral wall of the trough is provided with a third annular limiting step and a fourth annular limiting step, the third annular limiting step abutting and limiting the first annular limiting step, and the fourth annular limiting step abutting and limiting the second annular limiting step.

8. The mounting fixture as described in claim 6, characterized in that: The mounting platform has a wire passage hole that communicates with the receiving groove.

9. The mounting fixture as described in any one of claims 1 to 5, characterized in that: The hardness of both side plates and the hardness of the base plate are greater than the hardness of the extension bracket.