A three-layer and above inter-board connector based on a hair button

Abstract

This invention discloses a three-layer or higher inter-board connector based on snap-fit ​​buttons, belonging to the field of electrical connector technology. The connector includes a housing and a base assembly. The housing has a base mounting cavity and at least three mounting surfaces at different distances from the bottom surface for mounting printed circuit boards (PCBs). The base assembly is disposed within the base mounting cavity and contains several first snap-fit ​​electrical connection mechanisms and several second snap-fit ​​electrical connection mechanisms. PCBs mounted on the housing are electrically connected in pairs via either the first or second snap-fit ​​electrical connection mechanisms. By connecting at least three PCBs mounted on the housing in pairs via either the first or second snap-fit ​​electrical connection mechanisms, vertical interconnection between three-layer or higher PCBs is achieved.

Description

Technical Field

[0001] This invention relates to a three-layer or higher inter-board connector based on a bobble button, belonging to the field of electrical connector technology. Background Technology

[0002] In electronic devices, especially communication equipment, servers, high-performance computing clusters, and military electronic equipment, multiple printed circuit boards (PCBs) often need to be tightly assembled vertically or parallelly to achieve high-density, high-performance signal transmission and power distribution. This requires connectors to possess characteristics such as high density, low height, high performance, high reliability, and reusability. Traditional board-to-board connection solutions mainly include: 1. Using a male-female connector pairing method. Its disadvantages include a larger space requirement, especially in the height direction; limited pin count or pin density; and potential risk of poor contact under strong vibration or impact.

[0003] 2. Permanent connections via cables or flexible circuit boards. While reliable, this method completely eliminates the possibility of separation, causing significant inconvenience for equipment testing, maintenance, and upgrades.

[0004] To overcome the above shortcomings, the button connector was developed and has gradually become one of the mainstream solutions for high-speed, high-density board interconnection.

[0005] For example, Chinese patent document CN201520562834.1 discloses a button-type inter-board electrical connector that uses random threaded pins as contacts. A set of random threaded pins and accessories are mounted on an insulating mounting plate to form a button-type inter-board electrical connector. This button-type inter-board electrical connector has end-face contact with the printed circuit board, and the insertion and extraction force is zero. By installing one button-type inter-board connector between the upper and lower printed circuit boards, a vertical connection between the printed circuit boards can be completed.

[0006] For example, Chinese patent document CN202421207017.X discloses a 328-pin button connector, which uses a two-row, three-cavity, six-cavity structure. Each cavity's button and protective cap form a central contact, with an insulating dielectric body covering the central contacts and achieving a clearance fit within the dielectric body's internal holes, forming an insulating dielectric assembly. The insulating dielectric assembly is surrounded by a metal structure, forming an integral structure with the entire frame. Eight screw holes are used to achieve a secure connection with two parallel printed circuit boards. Guide posts are placed at the four diagonal corners on the two sides of the connector that contact the printed circuit boards to restrict the corresponding spatial degrees of freedom and improve contact accuracy.

[0007] However, the button connector provided by the aforementioned patent can only achieve vertical interconnection between two printed circuit boards, and cannot meet the vertical interconnection requirements between three or more printed circuit boards. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a three-layer or higher inter-board connector based on a bobble button.

[0009] This invention is achieved through the following technical solution: A three-layer or higher board-to-board connector based on a snap button includes a housing and a base assembly. The housing has a base mounting cavity and at least three mounting surfaces at different distances from the bottom surface of the housing for mounting printed circuit boards. The base assembly is disposed within the base mounting cavity and has a plurality of first snap button electrical connection mechanisms and a plurality of second snap button electrical connection mechanisms. Printed circuit boards mounted on the housing are electrically connected in pairs through the first snap button electrical connection mechanisms or the second snap button electrical connection mechanisms.

[0010] For the first button electrical connection mechanism, the base assembly is provided with two sets of first stepped holes and two first transition cavities. The upper end of the first stepped hole penetrates the top surface of the base assembly. The two first transition cavities are located on the lower side of the two sets of first stepped holes and are connected to the lower end of the two sets of first stepped holes. The base assembly has a potting cavity that communicates with the two first transition cavities on the lower side of the two first transition cavities, and the potting cavity penetrates the bottom surface of the base assembly. Both sets of the first stepped holes include multiple first stepped holes arranged side by side.

[0011] The first button electrical connection mechanism includes an adapter module and two sets of first button electrical contact components. The two sets of first button electrical contact components are respectively disposed in two sets of first stepped holes on the base assembly, and the upper ends of the two sets of first button electrical contact components extend to the outside of the base assembly, corresponding to the solderless interconnection with two different printed circuit boards. The adapter module is located in two first adapter cavities and a potting cavity, and is electrically connected to two sets of first button electrical contact assemblies.

[0012] The first button electrical contact assembly includes a first ball probe and a first button. The first ball probe is in clearance fit with the first stepped hole and extends partially outside the base assembly. The first button is in clearance fit with the first stepped hole, with its upper end abutting against the first ball probe and its lower end abutting against the adapter module, thereby realizing the electrical connection between the first ball probe and the adapter module. Inject adhesive into the potting cavity to form a potting block for fixing the base assembly and the adapter module inside the housing; The adapter module is one or a combination of busbars, wires, coaxial cables and differential lines.

[0013] For the second button electrical connection mechanism, the base assembly is provided with a set of second stepped holes, which includes multiple second stepped holes arranged side by side, and the second stepped holes penetrate the base assembly.

[0014] The second button electrical connection mechanism includes a set of second button electrical contact components. The set of second button electrical contact components includes multiple second button electrical contact components, and the multiple second button electrical contact components are correspondingly disposed in multiple second stepped holes. Both ends of the second button electrical contact components extend outside the base assembly, and the lower end of the second button electrical contact component is solderless interconnected with one of the printed circuit boards, and the upper end is solderless interconnected with another printed circuit board.

[0015] The second button electrical contact assembly includes an adapter pin and two second ball-head probes. The adapter pin has two flat ends and is located in the middle of the second stepped hole. The outer circle of the adapter pin has barbs that are interference-fitted with the second stepped hole. The two second ball-head probes are clearance-fitted with the second stepped hole and are correspondingly arranged at both ends of the second stepped hole, extending partially outside the base assembly. One end of each of the two second ball-head probes is connected to the adapter pin via a second button. The second button is clearance-fitted with the second stepped hole, thus achieving electrical connection between the second ball-head probes and the adapter pin.

[0016] The base assembly includes a first base and several second bases. The top of the first base has several base mounting slots. The number of the second button electrical connection mechanism, the second bases and the base mounting slots are the same, and the several second bases are arranged one-to-one in the several base mounting slots. The lower part of the second stepped hole is opened on the first base, and the upper part is opened on the second base.

[0017] The base mounting cavity is provided with a base limiting step near the top surface of the outer shell for limiting the position of the first base. The outer shell is provided with rivet holes at positions corresponding to each of the second bases, which are connected to the base mounting cavity.

[0018] The outer casing has multiple guide posts and threaded holes at each printed circuit board mounting location.

[0019] The beneficial effects of this invention are as follows: 1. The housing has at least three mounting surfaces at different distances from the bottom surface for mounting printed circuit boards (PCBs). This means the housing can support three or more PCBs. The PCBs mounted on the housing are electrically connected in pairs via a first or second button-type electrical connection mechanism, thus achieving vertical interconnection between the three or more PCBs. Furthermore, based on the elastic contact characteristics of the button-type components, the use of the first and second button-type electrical connection mechanisms to achieve vertical interconnection between the three or more PCBs ensures reliable signal transmission from the connector under certain axial and radial tolerances.

[0020] 2. While the printed circuit boards are electrically connected using the first or second button-type electrical connection mechanism, the relative positions of the printed circuit boards and the housing are positioned by guide posts. Then, the printed circuit boards are installed and fixed to the housing by screws, which enables the rapid installation and fixing of multiple printed circuit boards.

[0021] 3. The adapter pin provides support for the second buttons on both sides. Furthermore, compared to omitting the adapter pin and combining the second buttons on both sides into one, the adapter pin significantly reduces the length of the second buttons, avoiding a substantial increase in production costs due to an excessively large aspect ratio, and preventing situations where the second buttons cannot be manufactured using existing processes due to an excessively large aspect ratio.

[0022] 4. The overall structural design of the connector enables low-profile, high-density, and highly reliable interconnection between boards, and is compatible with various signal transmissions such as low frequency, high speed, radio frequency, and power. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 A magnified view of a portion at point A; Figure 3 This is a schematic diagram of the outer casing of the present invention; Figure 4 This is an exploded view of the base assembly of the present invention; Figure 5 This is a schematic diagram of the adapter pin of the present invention; Figure 6 This is a diagram showing the relative positions of the first ball-head probe and the pad in this invention.

[0024] In the diagram: 1-Outer shell, 101-First mounting surface, 102-Second mounting surface, 103-Third mounting surface, 104-Base mounting cavity, 105-Guide post, 106-Threaded hole, 107-Base limiting step, 108-Rivet hole, 2-Base assembly, 21-First stepped hole, 22-First transition cavity, 23-Plugging cavity, 24-Second stepped hole, 25-First base, 251-Base mounting groove, 26-Second base, 3-The 1-Printed circuit board, 4-Second printed circuit board, 5-Third printed circuit board, 6-First button electrical connection mechanism, 61-Adapter module, 62-Potting block, 63-First button electrical contact assembly, 631-First ball probe, 632-First button, 7-Second button electrical connection mechanism, 71-Second button electrical contact assembly, 711-Adapter pin, 7111-Barb, 712-Second button, 713-Second ball probe, 8-Pad. Detailed Implementation

[0025] The technical solution of the present invention will be further described below using the example of a three-layer printed circuit board mounted on the outer casing 1, but the scope of protection is not limited to the above.

[0026] like Figures 1 to 6 As shown, the present invention discloses a three-layer or higher board-to-board connector based on a button, comprising a housing 1 and a base assembly 2. The housing 1 is provided with a first mounting surface 101, a second mounting surface 102, and a third mounting surface 103 for mounting a first printed circuit board 3, a second printed circuit board 4, and a third printed circuit board 5, with the second mounting surface 102 located between the first mounting surface 101 and the third mounting surface 103. The housing 1 has a base mounting cavity 104, and the base assembly 2 is disposed within the base mounting cavity 104. The base assembly 2 is provided with a first button electrical connection mechanism 6 for electrically connecting the first printed circuit board 3 and the second printed circuit board 4, a second button electrical connection mechanism 7 for electrically connecting the first printed circuit board 3 and the third printed circuit board 5, and a second button electrical connection mechanism 7 for electrically connecting the second printed circuit board 4 and the third printed circuit board 5.

[0027] Specifically, the first printed circuit board 3 and the second printed circuit board 4 are electrically connected through the first button-type electrical connection mechanism 6, and the first printed circuit board 3 and the third printed circuit board 5, as well as the second printed circuit board 4 and the third printed circuit board 5, are electrically connected through the second button-type electrical connection mechanism 7, thereby achieving vertical interconnection between the three printed circuit boards. Simultaneously, based on the elastic contact characteristics of the button-type components, the use of the first button-type electrical connection mechanism 6 and the second button-type electrical connection mechanism 7 to achieve vertical interconnection between the three printed circuit boards can meet the requirement of reliable signal transmission from the connector under certain axial and radial tolerances.

[0028] In addition, one or more printed circuit boards can be installed on each mounting surface.

[0029] The first button electrical connection mechanism 6 is located between the second button electrical connection mechanism 7 for electrically connecting the first printed circuit board 3 and the third printed circuit board 5, and the second button electrical connection mechanism 7 for electrically connecting the second printed circuit board 4 and the third printed circuit board 5.

[0030] Specifically, such as Figure 1 As shown, the first button electrical connection mechanism 6 is arranged between two second button electrical connection mechanisms 7 along the length of the connector. This can minimize the distance between the two sets of first button electrical contact components 63, thereby reducing the volume of the adapter module 61 and the potting block 62, which is beneficial for miniaturizing the connector.

[0031] The base assembly 2 is provided with two sets of first stepped holes 21 and two first transition cavities 22. The upper end of the first stepped hole 21 penetrates the top surface of the base assembly 2. The two first transition cavities 22 are located on the lower side of the two sets of first stepped holes 21 and are connected to the lower end of the two sets of first stepped holes 21. The base assembly 2 has a glue-filling cavity 23 on the lower side of the two first transition cavities 22, which is connected to the two first transition cavities 22, and the glue-filling cavity 23 penetrates the bottom surface of the base assembly 2. Both sets of the first stepped holes 21 each include multiple first stepped holes 21 arranged side by side.

[0032] The first button electrical connection mechanism 6 includes a transfer module 61 and two sets of first button electrical contact components 63. The two sets of first button electrical contact components 63 are respectively disposed in two sets of first stepped holes 21 on the base assembly 2. The upper end of one set of first button electrical contact components 63 extends outside the base assembly 2 and is interconnected with the first printed circuit board 3 without soldering. The upper end of the other set of first button electrical contact components 63 extends outside the base assembly 2 and is interconnected with the second printed circuit board 4 without soldering. The adapter module 61 is located in the two first adapter cavities 22 and the potting cavity 23, and is electrically connected to two sets of first button electrical contact assemblies 63.

[0033] The first button electrical contact assembly 63 includes a first ball probe 631 and a first button 632. The first ball probe 631 is in clearance fit with the first stepped hole 21 and extends partially outside the base assembly 2. The first button 632 is in clearance fit with the first stepped hole 21, with its upper end abutting against the first ball probe 631 and its lower end abutting against the adapter module 61, thereby realizing the electrical connection between the first ball probe 631 and the adapter module 61. Glue is injected into the potting cavity 23 to form a potting block 62 for fixing the base assembly 2 and the adapter module 61 in the housing 1; The adapter module 61 is one or a combination of busbars, wires, coaxial cables and differential lines.

[0034] Specifically, the first button 632 is clearance-fitted with the first stepped hole 21, which provides space for the first button 632 to undergo elastic deformation under external pressure, and avoids excessive increase in friction between the first button 632 and the wall of the first stepped hole 21 after axial compression.

[0035] The first button 632 is an elastic contact formed by winding metal wire according to a certain process. The first ball probe 631 compresses the first button 632 under the pushing action of the solder pad 8 on the printed circuit board, giving the connector a certain amount of float and enabling it to work effectively within a certain axial tolerance. Simultaneously, the compressed first button 632 reacts to the first ball probe 631, pushing the ball head of the first ball probe 631 onto the solder pad 8 to achieve a reliable electrical connection. Furthermore, because the diameter of the ball head of the first ball probe 631 is much smaller than the diameter of the solder pad 8, the connector can reliably transmit signals within a certain radial tolerance. Figure 6 As shown. The electrical connection between the second ball probe 713 and the pad 8 on the printed circuit board is similar to that between the first ball probe 631 and the pad 8 on the printed circuit board, which enables the connector to reliably transmit signals within a certain axial and radial tolerance, thereby enabling the first printed circuit board 3, the second printed circuit board 4 and the third printed circuit board 5 to achieve solderless vertical interconnection.

[0036] The adapter module 61 is one or a combination of busbars, wires, coaxial cables and differential lines, used to realize the transmission of various signals such as low frequency, high speed, radio frequency and power, so that the signal can be transmitted horizontally between the first printed circuit board 3 and the second printed circuit board 4 in a very small space.

[0037] The base assembly 2 is provided with two sets of second stepped holes 24. Each set of second stepped holes 24 includes multiple second stepped holes 24 arranged side by side, and the second stepped holes 24 penetrate the base assembly 2.

[0038] The second button electrical connection mechanism 7 includes two sets of second button electrical contact components 71, and the two sets of second button electrical contact components 71 are respectively disposed in two sets of second stepped holes 24. The ends of the two sets of second button electrical contact components 71 extend to the outside of the base assembly 2, and the lower ends of the two sets of second button electrical contact components 71 are solderless interconnected with the third printed circuit board 5. The upper end of one set of second button electrical contact components 71 is solderless interconnected with the first printed circuit board 3, and the upper end of the other set of second button electrical contact components 71 is solderless interconnected with the second printed circuit board 4.

[0039] The second button electrical contact assembly 71 includes an adapter pin 711 and two second ball-head probes 713. The two ends of the adapter pin 711 are flat. The adapter pin 711 is located in the middle of the second stepped hole 24, and the outer circle of the adapter pin 711 is provided with barbs 7111 that are interference-fitted with the second stepped hole 24. The two second ball-head probes 713 are clearance-fitted with the second stepped hole 24 and are correspondingly arranged at both ends of the second stepped hole 24, and partially extend outside the base assembly 2. One end of each of the two second ball-head probes 713 is connected to the adapter pin 711 through a second button 712. The second button 712 is clearance-fitted with the second stepped hole 24, and realizes the electrical connection between the second ball-head probes 713 and the adapter pin 711.

[0040] Specifically, the adapter pin 711 provides support for the second buttons 712 on both sides. Furthermore, compared to omitting the adapter pin 711 and combining the two second buttons 712 into one, the adapter pin 711 significantly reduces the length of the second buttons 712, avoiding a significant increase in production costs due to an excessively large aspect ratio, and preventing situations where the second buttons 712 cannot be manufactured using existing processes due to an excessively large aspect ratio.

[0041] The second button electrical contact assembly 71 is compatible with the transmission of various signals, including low frequency, high speed, radio frequency, and power, and can be adjusted according to specific requirements.

[0042] The base assembly 2 includes a first base 25 and two second bases 26. The top of the first base 25 has two base mounting grooves 251, and the two second bases 26 are respectively disposed in the two base mounting grooves 251. The lower parts of the two sets of second stepped holes 24 are respectively disposed on the first base 25, and the upper parts of the two sets of second stepped holes 24 are respectively disposed on the two second bases 26.

[0043] Specifically, the base assembly 2 is split into a first base 25 and two second bases 26, and the lower parts of the two sets of second stepped holes 24 are opened on the first base 25 and the lower parts are correspondingly opened on the two second bases 26, so as to facilitate the assembly of the second button electrical contact assembly 71 into the second stepped hole 24.

[0044] The base mounting cavity 104 has a base limiting step 107 located near the first mounting surface 101; The outer shell 1 has rivet holes 108 at positions corresponding to the two second bases 26, which are respectively connected to the base mounting cavity 104.

[0045] Specifically, the top of the first base 25 is limited by the base limiting step 107, and the bottom of the first base 25 is fixedly connected to the outer shell 1 by the glue block 62, thereby fixing the first base 25 into the base mounting cavity 104 on the outer shell 1. After the second base 26 is installed into the base mounting cavity 104 and the corresponding base mounting groove 251, a spot riveting operation is performed through the spot riveting hole 108 to achieve a fixed connection between the second base 26 and the outer shell 1.

[0046] Multiple guide posts 105 are respectively provided on the first mounting surface 101, the second mounting surface 102 and the third mounting surface 103 of the outer casing 1; The outer casing 1 has threaded holes 106 on its first mounting surface 101, second mounting surface 102 and third mounting surface 103 respectively.

[0047] Specifically, the first printed circuit board 3, the second printed circuit board 4, and the third printed circuit board 5 have positioning holes machined at positions corresponding to the guide posts 105. By inserting the guide posts 105 into the corresponding positioning holes, the relative positions of the first printed circuit board 3, the second printed circuit board 4, and the third printed circuit board 5 with the outer casing 1 can be achieved. Threaded holes 106 are provided on the outer casing 1 to facilitate the quick installation and fixation of the first printed circuit board 3, the second printed circuit board 4, and the third printed circuit board 5 onto the outer casing 1 using screws, and to facilitate the disassembly and maintenance of the printed circuit boards.

Claims

1. A three-layer or higher inter-board connector based on a button, characterized in that: The device includes a housing (1) and a base assembly (2). The housing (1) has a base mounting cavity (104). The housing (1) has at least three mounting surfaces at different distances from the bottom surface of the housing (1) for mounting printed circuit boards. The base assembly (2) is located inside the base mounting cavity (104). The base assembly (2) has several first button electrical connection mechanisms (6) and several second button electrical connection mechanisms (7). The printed circuit boards mounted on the housing (1) are electrically connected to each other in pairs through the first button electrical connection mechanism (6) or the second button electrical connection mechanism (7).

2. The three-layer or higher inter-board connector based on a button as described in claim 1, characterized in that: For the first button electrical connection mechanism (6), the base assembly (2) is provided with two sets of first stepped holes (21) and two first transition cavities (22). The upper end of the first stepped hole (21) penetrates the top surface of the base assembly (2). The two first transition cavities (22) are located on the lower side of the two sets of first stepped holes (21) and are connected to the lower end of the two sets of first stepped holes (21). The base assembly (2) has a potting cavity (23) connected to the two first transition cavities (22) on the lower side of the two first transition cavities (22), and the potting cavity (23) penetrates the bottom surface of the base assembly (2). Both sets of the first stepped holes (21) include multiple first stepped holes (21) arranged side by side.

3. The three-layer or higher inter-board connector based on a button as described in claim 2, characterized in that: The first button electrical connection mechanism (6) includes a converter module (61) and two sets of first button electrical contact components (63). The two sets of first button electrical contact components (63) are respectively provided in the two sets of first stepped holes (21) on the base assembly (2), and the upper ends of the two sets of first button electrical contact components (63) extend to the outside of the base assembly (2) to be solderless interconnected with two different printed circuit boards. The adapter module (61) is located in two first adapter cavities (22) and a potting cavity (23), and is electrically connected to two sets of first button electrical contact assemblies (63).

4. The three-layer or higher inter-board connector based on a button as described in claim 3, characterized in that: The first button electrical contact assembly (63) includes a first ball probe (631) and a first button (632). The first ball probe (631) is in clearance fit with the first stepped hole (21) and extends partially outside the base assembly (2). The first button (632) is in clearance fit with the first stepped hole (21). Its upper end abuts against the first ball probe (631) and its lower end abuts against the adapter module (61), thereby realizing the electrical connection between the first ball probe (631) and the adapter module (61). Inject adhesive into the potting cavity (23) to form a potting block (62) for fixing the base assembly (2) and the adapter module (61) inside the housing (1). The adapter module (61) is one or more of the following: busbar, conductor, coaxial cable and differential line.

5. The three-layer or higher inter-board connector based on a button as described in claim 1, characterized in that: For the second button electrical connection mechanism (7), the base assembly (2) is provided with a set of second stepped holes (24), which includes multiple second stepped holes (24) arranged side by side, and the second stepped holes (24) penetrate the base assembly (2).

6. The three-layer or higher inter-board connector based on a button as described in claim 5, characterized in that: The second button electrical connection mechanism (7) includes a set of second button electrical contact components (71). The set of second button electrical contact components (71) includes multiple second button electrical contact components (71), and the multiple second button electrical contact components (71) are respectively disposed in multiple second stepped holes (24). Both ends of the second button electrical contact components (71) extend to the outside of the base assembly (2), and the lower end of the second button electrical contact components (71) is solderless connected to one of the printed circuit boards, and the upper end is solderless connected to another printed circuit board.

7. The three-layer or higher inter-board connector based on a button as described in claim 6, characterized in that: The second button electrical contact assembly (71) includes an adapter pin (711) and two second ball probes (713). The two ends of the adapter pin (711) are flat. The adapter pin (711) is located in the middle of the second stepped hole (24). The outer circle of the adapter pin (711) is provided with barbs (7111) that are interference fit with the second stepped hole (24). The two second ball probes (713) are all clearance fit with the second stepped hole (24) and are arranged at both ends of the second stepped hole (24) respectively, and partially extend to the outside of the base assembly (2). One end of the two second ball probes (713) is connected to the adapter pin (711) through a second button (712). The second button (712) is clearance fit with the second stepped hole (24) and realizes the electrical connection between the second ball probes (713) and the adapter pin (711).

8. The three-layer or higher inter-board connector based on a button as described in claim 5, characterized in that: The base assembly (2) includes a first base (25) and several second bases (26). The top of the first base (25) is provided with several base mounting slots (251). The number of the second button electrical connection mechanism (7), the second bases (26) and the base mounting slots (251) are the same, and the several second bases (26) are arranged one-to-one in the several base mounting slots (251). The lower part of the second stepped hole (24) is opened on the first base (25), and the upper part is opened on the second base (26).

9. The three-layer or higher inter-board connector based on a button as described in claim 8, characterized in that: The base mounting cavity (104) has a base limiting step (107) for limiting the first base (25) at a position near the top surface of the outer shell (1). The outer shell (1) is provided with rivet holes (108) at positions corresponding to each second base (26) and communicating with the base mounting cavity (104).

10. The three-layer or higher inter-board connector based on a button as described in claim 1, characterized in that: The outer casing (1) is provided with multiple guide posts (105) and threaded holes (106) at each printed circuit board mounting location.

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