Spliced circuit board
By combining the main circuit board, sub-circuit boards, connectors, and support frame, the problems of insufficient connection strength and anti-interference ability of the assembled circuit boards are solved, achieving a stable connection, simplifying production, and improving the reliability and applicability of the circuit boards.
Patent Information
- Application Number
- CN202423317175.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-12-16
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing composite circuit board technology suffers from problems such as insufficient connection strength, susceptibility to external impacts, significant impact from static electricity and electromagnetic interference, cumbersome soldering process, and difficulty in adapting to large-scale production.
The design employs a main circuit board, sub-circuit board, connectors, and support frame. A stable connection is achieved through slots and snap-fit devices. The support frame provides mechanical support and prevents static electricity and electromagnetic interference. The connectors use gold-plated pins to improve conductivity. The support frame is made of ABS plastic or aluminum alloy to improve mechanical strength, and elastic pads absorb vibration.
It improves the connection strength and stability of the assembled circuit boards, simplifies the production process, reduces costs, enhances anti-interference capabilities and ease of maintenance, and ensures the long-term reliability and applicability of the circuit boards.
Smart Images
Figure CN223681277U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the design of circuit boards in electronic devices, and in particular to a combined circuit board. BACKGROUND
[0002] With the miniaturization and diversification of electronic products, the design and manufacture of circuit boards have become increasingly complex. Traditional single-piece circuit boards have been unable to meet the needs of modern electronic devices, so combining multiple circuit boards together in a specific way to form a combined circuit board has become an important technical trend. This technology not only improves the space utilization of circuit boards, but also enhances the functionality and flexibility of circuit boards. Combined circuit boards have a wide range of applications, covering consumer electronics, industrial control, medical devices, and other fields, greatly promoting the innovation and development of electronic products. Currently, common combined circuit board technologies mainly include soldering technology and plug-in technology. Soldering technology adds solder between multiple circuit boards to firmly connect them together. The advantage of this method is that the connection is stable and not prone to loosening, but the soldering process is complex and time-consuming, and once soldering is complete, subsequent maintenance and replacement are difficult. Plug-in technology is to design special slots and pins so that multiple circuit boards can be quickly connected and separated through simple plug-in and plug-out actions. The advantage of this method is that it is easy to operate, maintain and replace, but the disadvantage is that the connection strength is low and is easily affected by external shocks, leading to poor contact. Existing combined circuit board technologies have their own advantages, but also have obvious defects. Although soldering technology has a stable connection, the soldering process is complicated and difficult to meet the needs of large-scale production; although plug-in technology is easy to operate, it has insufficient connection strength and poor reliability, which can easily lead to unstable signal transmission between circuit boards. In addition, existing combined circuit board technologies lack effective protection measures for electrical connections between multiple circuit boards, which are easily affected by static electricity and electromagnetic interference, thereby affecting the performance and stability of the entire electronic device. CONTENT OF THE UTILITY MODEL
[0003] The purpose of the present application is to overcome the above technical problems, and to provide a combined circuit board
[0004] The utility model provides a kind of combined circuit board, including main circuit board, sub-circuit board, connector and support frame, the main circuit board is provided with slot, the sub-circuit board is inserted into the main circuit board by the slot, and is electrically connected with the main circuit board by the connector, the support frame is installed in the four around of the main circuit board, the support frame is equipped with fixed hole, the support frame is fixed on the main circuit board by screw, the both sides of the connector are equipped with buckle device, the buckle device is locked automatically after the sub-circuit board is inserted into the slot, prevents the sub-circuit board from falling off.By using the above technical scheme, the connection strength and stability of the combined circuit board are improved, and reliable electrical connection and mechanical fixation are achieved through the design of the connector and the buckle device, reducing the problem of poor contact caused by external impact.At the same time, the support frame not only plays a fixing and supporting role, but also effectively prevents static electricity and electromagnetic interference, ensuring the normal operation of the circuit board.In addition, the scheme simplifies the combination process and reduces production costs, and the design of the slot and the buckle device makes the installation and disassembly of the sub-circuit board more convenient and fast, which is suitable for mass production and automatic assembly line.It is preferred that the main circuit board is covered with copper foil with a thickness of 1.6 mm.By using the above technical scheme, the main circuit board is covered with copper foil with a thickness of 1.6 mm, which improves the electrical conductivity and mechanical strength of the circuit board and ensures the stability and reliability of the main circuit board during long-term use.It is preferred that the sub-circuit board is covered with copper foil with a thickness of 1.0 mm.By using the above technical scheme, the sub-circuit board is covered with copper foil with a thickness of 1.0 mm, which ensures that the sub-circuit board has good electrical conductivity and high mechanical strength, while reducing the weight of the circuit board for easy transportation and installation.In addition, the copper foil with this thickness can effectively reduce the loss during signal transmission, improving the stability and reliability of signal transmission.It is preferred that the connector is made of gold-plated pins.By using the above technical scheme, the connector is made of gold-plated pins, which can significantly improve the electrical conductivity and corrosion resistance of the connector, ensuring stable electrical connection after long-term use.The surface of the gold-plated pins is smooth, with low contact resistance, reducing the loss during signal transmission and improving the efficiency and quality of signal transmission.Meanwhile, the gold-plated material has good oxidation resistance, prolonging the service life of the connector and reducing the maintenance frequency and cost.It is preferred that the support frame is made of ABS plastic, the fixed hole has a diameter of 3 mm, and the screw is an M3 stainless steel screw.By using the above technical scheme, the support frame is made of ABS plastic, which has good insulation performance and high mechanical strength, effectively preventing static electricity and electromagnetic interference, and protecting the circuit board from external environment.The fixed hole has a diameter of 3 mm, ensuring the stable fixation of the screw and improving the connection strength and reliability of the support frame and the main circuit board.The screw is an M3 stainless steel screw, which has excellent corrosion resistance and mechanical strength, prolonging the service life of the support frame and ensuring its stability and safety during long-term use.Preferably, the support frame is made of aluminum alloy or polycarbonate to improve support strength and durability. By adopting the above technical solution, the use of aluminum alloy or polycarbonate as the material for the support frame significantly improves its support strength and durability, thereby enhancing the overall structural stability of the assembled circuit board. Simultaneously, these materials possess good mechanical properties and corrosion resistance, extending the service life of the support frame and ensuring reliable operation of the circuit board under prolonged use and various environmental conditions. Preferably, an elastic gasket with a thickness of 0.5mm is also included, placed between the main circuit board and the sub-circuit board to absorb external vibrations and impacts, improving the connector's service life. By adopting the above technical solution, the addition of an elastic gasket with a thickness of 0.5mm, placed between the main circuit board and the sub-circuit board, effectively absorbs external vibrations and impacts, reducing connector damage caused by the external environment and extending the connector's service life. Simultaneously, the elastic gasket provides an additional electrical connection path, enhancing the stability of signal transmission. Preferably, the elastic gasket provides an additional electrical connection path. By adopting the above technical solution, the elastic gasket can not only absorb external vibrations and shocks, improving the service life of the connector, but also provide additional electrical connection paths, enhancing the stability of signal transmission. Preferably, the number and spacing of the connector pins are adapted to different electrical connection requirements. By adopting the above technical solution, the number and spacing of the connector pins can be flexibly adjusted according to different electrical connection requirements, thereby ensuring a more stable and reliable electrical connection between the sub-circuit board and the main circuit board. This not only improves the applicability of the assembled circuit board, but also enhances the performance and compatibility of the circuit board in various application scenarios. Preferably, the locking device includes a pair of symmetrically arranged elastic arms, one end of each elastic arm is fixed to the connector, and the other end has a protrusion. The protrusion engages with the side wall of the slot after the sub-circuit board is inserted into the slot to achieve locking. By adopting the above technical solution, the design of the locking device allows the sub-circuit board to be automatically locked after being inserted into the slot of the main circuit board, effectively preventing the sub-circuit board from falling off due to external impacts during use, and improving the connection strength and stability of the assembled circuit board. At the same time, this design simplifies the installation and disassembly process of the sub-circuit board, facilitates maintenance and replacement, reduces production costs, and is suitable for large-scale production and automated assembly lines. In addition, the elastic arm structure of the latching device has a certain self-adjusting capability, which can adapt to sub-circuit boards of different sizes, improving the system's compatibility and flexibility. Attached Figure Description
[0005] Figure 1 This is a schematic diagram of the overall structure.
[0006] Figure 2 This is a structural schematic diagram highlighting the shock-absorbing pad and elastic gasket in the embodiments of this application.
[0007] Reference signs: 1, main circuit board; 2, sub-circuit board; 3, connector; 4, support frame; 11, slot; 41, screw; 42, shock pad; 5, buckle device; 51, elastic arm; 52, protrusion; 21, elastic gasket. DETAILED DESCRIPTION
[0008] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings, and the described embodiments are only possible technical implementations of the present application, not all possible implementations. Those skilled in the art can easily obtain other embodiments by combining the embodiments of the present application without creative labor, and these embodiments are also within the protection scope of the present application.
[0009] The inventors of the present application found that with the miniaturization and functional diversification of electronic products, the design and manufacture of circuit boards have become increasingly complex. Traditional single-piece circuit boards have been unable to meet the needs of modern electronic devices, so combining multiple circuit boards together in a specific way to form a combined circuit board has become an important technical trend. This technology not only improves the space utilization of the circuit board, but also enhances the functionality and flexibility of the circuit board. However, in practical applications, how to efficiently and reliably realize the combination of multiple circuit boards is still a problem to be solved. Therefore, the present application mainly uses the following combined circuit board, which includes a main circuit board 1, a sub-circuit board 2, a connector 3 and a support frame 4, the main circuit board 1 is provided with a slot 11, the sub-circuit board 2 is inserted into the main circuit board 1 through the slot 11, and is electrically connected to the main circuit board 1 through the connector 3, the support frame 4 is installed around the main circuit board 1, the support frame 4 is provided with a fixing hole, the support frame 4 is fixed on the main circuit board 1 through a screw 41, both sides of the connector 3 are provided with a buckle device 5, the buckle device 5 is automatically locked after the sub-circuit board 2 is inserted into the slot 11, preventing the sub-circuit board 2 from falling off, improving the connection strength and stability of the combined circuit board, simplifying the combination process, reducing production cost, enhancing the anti-interference ability and maintenance convenience of the circuit board, and the following further detailed description of the present application.
[0010] Embodiment 1
[0011] The application embodiment provides a combined circuit board, which comprises a main circuit board 1, a sub-circuit board 2, a connector 3 and a support frame 4. The main circuit board 1 is provided with a slot 11, the sub-circuit board 2 is inserted into the main circuit board 1 through the slot 11 and is electrically connected with the main circuit board 1 through the connector 3. The support frame 4 is installed around the main circuit board 1, the support frame 4 is provided with fixing holes, and the support frame 4 is fixed on the main circuit board 1 through screws 41. The connector 3 is provided with buckle devices 5 on both sides, the buckle devices 5 are automatically locked after the sub-circuit board 2 is inserted into the slot 11, and the sub-circuit board 2 is prevented from falling off.
[0012] Specifically, the main circuit board 1 comprises a copper foil cladding layer with a thickness of 1.6 mm. The copper foil cladding layer can be made of high-purity copper material to improve the electrical conductivity and heat conduction efficiency. The size of the main circuit board 1 is 200 mm x 150 mm, which can be adjusted according to actual needs. The surface of the main circuit board 1 can be subjected to oxidation resistance treatment to prolong the service life. The slot 11 provided on the main circuit board 1 can adopt a standard PCB slot 11, and the width and depth of the slot 11 should match the thickness of the sub-circuit board 2 to ensure that the sub-circuit board 2 can be smoothly inserted and kept stable.
[0013] Specifically, the sub-circuit board 2 also adopts a copper foil cladding layer with a thickness of 1.0 mm. The size of the sub-circuit board 2 is 100 mm x 75 mm, which can also be adjusted according to actual needs. The surface of the sub-circuit board 2 can be subjected to oxidation resistance and corrosion resistance treatment to improve its durability. The slot 11 part of the sub-circuit board 2 can adopt a gold plating process to improve the electrical conductivity and corrosion resistance.
[0014] Specifically, the connector 3 adopts gold-plated pins, the number of which is 40 and the spacing is 2.54 mm. The gold-plated pins can improve the electrical conductivity and corrosion resistance of the connector 3 to ensure the stability of long-term use. The shell of the connector 3 can be made of high-temperature-resistant and flame-retardant engineering plastic to improve safety and reliability. The pins of the connector 3 can be designed to be detachable to facilitate maintenance and replacement. The connector 3 is provided with buckle devices 5 on both sides, the buckle devices 5 comprise a pair of symmetrically arranged elastic arms 51, one end of each elastic arm 51 is fixed on the connector 3, the other end is provided with a protrusion 52, the protrusion 52 cooperates with the side wall of the slot 11 after the sub-circuit board 2 is inserted into the slot 11 to realize locking. The elastic arms 51 of the buckle devices 5 can be made of spring steel material to ensure their elasticity and durability.
[0015] Specifically, the support frame 4 is made of ABS plastic with a thickness of 2mm and a black color. ABS plastic has good insulation performance and mechanical strength, which can effectively prevent static electricity and electromagnetic interference. The four corners of the support frame 4 are provided with fixing holes with a diameter of 3mm, and the screws 41 are M3 stainless steel screws 41 with a length of 8mm. The stainless steel screws 41 have good corrosion resistance and mechanical strength, which can ensure the stability and durability of the support frame 4. The inner side of the support frame 4 can be provided with shock pads 42 to reduce the influence of external vibration on the circuit board.
[0016] The implementation principle of the embodiment is:
[0017] During assembly, first, the support frame 4 is fixed around the main circuit board 1 by screws 41, ensuring that the support frame 4 is tightly attached to the main circuit board 1. The support frame 4 not only plays a role in fixing and supporting, but also effectively prevents static electricity and electromagnetic interference, ensuring the normal operation of the circuit board. Then, the sub-circuit board 2 is aligned with the slot 11 on the main circuit board 1 and gently inserted. When the sub-circuit board 2 is completely inserted, the clasp device 5 on both sides of the connector 3 will automatically lock, preventing the sub-circuit board 2 from falling off. The entire process is simple to operate and suitable for mass production and automated assembly lines. Use a multimeter to detect whether the electrical connection between the sub-circuit board 2 and the main circuit board 1 is normal. If there is an abnormality, adjust it in time. When replacing or maintaining the sub-circuit board 2, simply press the clasp device 5 and gently remove the sub-circuit board 2 to avoid damaging the circuit board. Regularly check the status of the support frame 4 and the connector 3, and replace them in time if they are worn or damaged. The excellent materials and design of the support frame 4 and the connector 3 can ensure the long-term stability and reliability of the circuit board.
[0018] Embodiment 2
[0019] The difference between this embodiment and the above-mentioned embodiments is that the material of the support frame 4 is changed to aluminum alloy or polycarbonate to improve the support strength and durability.
[0020] Specifically, the support frame 4 is made of aluminum alloy material with a thickness of 2mm and a silver color. Aluminum alloy has high mechanical strength and good heat dissipation performance, which can effectively improve the stability and heat dissipation effect of the support frame 4. The four corners of the support frame 4 are provided with fixing holes with a diameter of 3mm, and the screws 41 are M3 stainless steel screws 41 with a length of 8mm. The stainless steel screws 41 have good corrosion resistance and mechanical strength, which can ensure the stability and durability of the support frame 4. The inner side of the support frame 4 can be provided with shock pads 42 to reduce the influence of external vibration on the circuit board.
[0021] Specifically, the support frame 4 can also be made of polycarbonate material with a thickness of 2mm and a transparent color. Polycarbonate has excellent mechanical strength and weather resistance, which can effectively improve the stability and durability of the support frame 4. The four corners of the support frame 4 are provided with fixing holes with a diameter of 3mm, and M3 stainless steel screws 41 with a length of 8mm are used. The stainless steel screws 41 have good corrosion resistance and mechanical strength, which can ensure the stability and durability of the support frame 4. The inner side of the support frame 4 can be provided with shock pads 42 to reduce the influence of external vibration on the circuit board.
[0022] The implementation principle of the embodiment is:
[0023] During assembly, first, the support frame 4 is fixed around the main circuit board 1 by screws 41, ensuring that the support frame 4 is tightly attached to the main circuit board 1. The support frame 4 not only plays a fixing and supporting role, but also effectively prevents static electricity and electromagnetic interference, ensuring the normal operation of the circuit board. Then, the sub-circuit board 2 is aligned with the slot 11 on the main circuit board 1 and gently inserted. When the sub-circuit board 2 is completely inserted, the clasp device 5 on both sides of the connector 3 will automatically lock, preventing the sub-circuit board 2 from falling off. The whole process is simple to operate and suitable for mass production and automated assembly lines. Use a multimeter to detect whether the electrical connection between the sub-circuit board 2 and the main circuit board 1 is normal. If there is an abnormality, adjust it in time. When replacing or maintaining the sub-circuit board 2, simply press the clasp device 5 and gently remove the sub-circuit board 2 to avoid damaging the circuit board. Regularly check the status of the support frame 4 and the connector 3, and replace them in time if they are worn or damaged. The excellent materials and design of the support frame 4 can ensure the long-term stability and reliability of the circuit board. In particular, the choice of aluminum alloy and polycarbonate material can significantly improve the mechanical strength and durability of the support frame 4, further enhancing the overall performance of the circuit board.
[0024] Embodiment 3
[0025] The difference between this embodiment and the above-mentioned embodiments is that an elastic gasket 21 is added between the main circuit board 1 and the sub-circuit board 2 to absorb external vibrations and impacts, improving the service life of the connector 3. The elastic gasket 21 also provides an additional electrical connection path to enhance the stability of signal transmission.
[0026] Specifically, the elastic gasket 21 is made of conductive rubber material with a thickness of 0.5mm. Conductive rubber has good electrical conductivity and elasticity, which can effectively absorb external vibrations and impacts, improving the service life of the connector 3. The shape of the elastic gasket 21 can match the contact surface of the main circuit board 1 and the sub-circuit board 2 to ensure good contact effect. The surface of the elastic gasket 21 can be treated with anti-oxidation to prolong the service life.
[0027] Specifically, the elastic gasket 21 can also provide additional electrical connection paths to enhance the stability of signal transmission. The interior of the elastic gasket 21 can be embedded with conductive fibers or wires to improve electrical conductivity and anti-interference ability. The thickness of the elastic gasket 21 can be adjusted according to actual needs to meet different application scenarios.
[0028] The implementation principle of this embodiment is:
[0029] During assembly, the elastic gasket 21 is first placed between the main circuit board 1 and the sub-circuit board 2, and then the sub-circuit board 2 is aligned with the socket 11 on the main circuit board 1 and gently inserted. The elastic gasket 21 can effectively absorb external vibrations and impacts, improving the service life of the connector 3. At the same time, the elastic gasket 21 can also provide additional electrical connection paths to enhance the stability of signal transmission. When the sub-circuit board 2 is fully inserted, the clamping device 5 on both sides of the connector 3 will automatically lock, preventing the sub-circuit board 2 from falling off. The entire process is simple to operate and suitable for mass production and automated assembly lines. Use a multimeter to detect whether the electrical connection between the sub-circuit board 2 and the main circuit board 1 is normal, and if there is an abnormality, adjust it in a timely manner. When replacing or maintaining the sub-circuit board 2, simply press the clamping device 5 and gently remove the sub-circuit board 2 to avoid damaging the circuit board. Regularly check the status of the support frame 4, the connector 3, and the elastic gasket 21, and replace them in a timely manner if they are worn or damaged. The excellent materials and design of the elastic gasket 21 can significantly improve the overall performance and stability of the combined circuit board, especially in terms of vibration resistance and anti-interference performance.
[0030] Embodiment 4
[0031] The difference between this embodiment and the above-mentioned embodiments is that the number and pitch of the pins of the connector 3 are adapted to different electrical connection requirements.
[0032] Specifically, the number of pins of the connector 3 can be adjusted to 20 or 60, and the pitch can be adjusted to 1.27mm or 5.08mm. According to the actual application scenario, appropriate pin number and pitch can be selected to meet different electrical connection requirements. For example, for low-density connections, fewer pin numbers and larger pitches can be selected; for high-density connections, more pin numbers and smaller pitches can be selected. The pins of the connector 3 can be plated with gold or silver to improve electrical conductivity and corrosion resistance.
[0033] Specifically, the shell of the connector 3 can be made of high-temperature-resistant and flame-retardant engineering plastic to improve safety and reliability. The pins of the connector 3 can be designed to be detachable for easy maintenance and replacement. The connector 3 is provided with buckle devices 5 on both sides, which include a pair of symmetrically arranged elastic arms 51. One end of each elastic arm 51 is fixed on the connector 3, and the other end is provided with a protrusion 52 that cooperates with the side wall of the slot 11 after the sub-circuit board 2 is inserted into the slot 11, achieving locking. The elastic arms 51 of the buckle devices 5 can be made of spring steel to ensure their elasticity and durability.
[0034] The implementation principle of the embodiment is:
[0035] During assembly, first, the support frame 4 is fixed around the main circuit board 1 by screws 41, ensuring that the support frame 4 is tightly attached to the main circuit board 1. The support frame 4 not only serves as a fixing and supporting role, but also effectively prevents static and electromagnetic interference, ensuring the normal operation of the circuit board. Next, the sub-circuit board 2 is aligned with the slot 11 on the main circuit board 1 and gently inserted. When the sub-circuit board 2 is fully inserted, the buckle devices 5 on both sides of the connector 3 will automatically lock, preventing the sub-circuit board 2 from falling off. The entire process is simple to operate and suitable for mass production and automated assembly lines. Use a multimeter to check if the electrical connection between the sub-circuit board 2 and the main circuit board 1 is normal. If there is an abnormality, adjust it in time. When replacing or maintaining the sub-circuit board 2, simply press the buckle device 5 and gently remove the sub-circuit board 2 to avoid damaging the circuit board. Regularly check the status of the support frame 4 and the connector 3, and replace them in time if they are worn or damaged. The specific adjustment method of the number and spacing of the pins of the connector 3 can be flexibly selected according to actual needs to meet different electrical connection requirements, further improving the overall performance and applicability of the combined circuit board.
[0036] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application. Therefore, any equivalent changes made in accordance with the structure, shape, and principle of the present application should be covered within the protection scope of the present application.
Claims
1. A modular circuit board, characterized by, The utility model relates to a circuit board connection structure, including main circuit board (1), subcircuit board (2), connector (3) and support frame (4), be provided with slot (11) on main circuit board (1), subcircuit board (2) is inserted main circuit board (1) through slot (11), and is electrically connected with main circuit board (1) through connector (3), support frame (4) is installed in the four around of main circuit board (1), be equipped with fixed hole on support frame (4), and support frame (4) is fixed on main circuit board (1) through screw (41), and both sides of connector (3) are equipped with buckle device (5), and buckle device (5) is locked automatically after subcircuit board (2) is inserted slot (11), prevents subcircuit board (2) from falling off.
2. The assembled circuit board according to claim 1, wherein The main circuit board (1) is covered with copper foil, and the thickness is 1.6 mm.
3. The assembled circuit board of claim 1, wherein, The subcircuit board (2) is covered with copper foil, and the thickness is 1.0 mm.
4. The assembled circuit board of claim 1, wherein, The connector (3) is plated with gold pins.
5. The assembled circuit board of claim 1, wherein, The support frame (4) is made of ABS plastic, the fixed hole has a diameter of 3 mm, and the screw (41) is an M3 stainless steel screw (41).
6. The assembled circuit board of claim 1, wherein, The support frame (4) is made of aluminum alloy or polycarbonate to improve the support strength and durability.
7. The assembled circuit board of claim 1, wherein, An elastic gasket (21) is further included, which has a thickness of 0.5 mm and is placed between the main circuit board (1) and the subcircuit board (2) to absorb external vibration and impact and improve the service life of the connector (3).
8. The assembled circuit board of claim 7, wherein, The elastic gasket (21) also provides an additional electrical connection path.
9. The assembled circuit board of claim 1, wherein, The number and spacing of the pins of the connector (3) are adapted to different electrical connection requirements.
10. The assembled circuit board of claim 1, wherein, The buckle device (5) includes a pair of symmetrically arranged elastic arms (51), one end of each elastic arm (51) is fixed on the connector (3), and the other end is provided with a protrusion (52), which cooperates with the side wall of the slot (11) after the subcircuit board (2) is inserted into the slot (11) to achieve locking.