Energy-saving and environment-friendly high-low voltage power distribution cabinet
By designing automatic ejection mechanism, reminder mechanism and speed control mechanism in high and low voltage distribution cabinets, troublesome problems during electrical device maintenance and disassembly are solved, and more convenient operation and more stable equipment use are achieved.
Patent Information
- Application Number
- CN202411656263.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-02-14
AI Technical Summary
The existing energy-saving and environmentally friendly high and low voltage distribution cabinets are more troublesome in the maintenance and disassembly of electrical components, which affects the convenience of future maintenance work.
A high and low voltage distribution cabinet including an automatic ejection mechanism, a reminder mechanism and a speed control mechanism is designed. The automatic ejection mechanism automatically ejects forward through the ejection rack, which facilitates the maintenance and disassembly of electrical components; the reminder mechanism reminds the staff to be pushed to the appropriate position through the air pressure chamber and the ringing; the speed control mechanism slows down the speed of the ejection rack through the rollers and resistance blocks. Prevent shock.
Through the design of the automatic pop-up mechanism, the installation and maintenance process of electrical devices is simplified, the reminder mechanism improves the operation convenience of staff, and the speed control mechanism enhances the stability and use safety of equipment.
Smart Images

Figure CN119448029A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of power distribution cabinets, and in particular to an energy-saving and environment-friendly high and low voltage power distribution cabinet. Background Art
[0002] High and low voltage distribution cabinets are distribution equipment used for power distribution, control, metering and cable connection in power supply systems. Generally, power supply bureaus and substations use high voltage switch cabinets, which are then stepped down by transformers and led out to low voltage distribution cabinets. Low voltage distribution cabinets are then led to distribution boards, control boxes and switch boxes for each power user. The equipment inside is a distribution device that is assembled into one by some switches, circuit breakers, fuses, buttons, indicator lights, meters, wires and other protective devices to meet the design functional requirements.
[0003] The patent document with publication number CN118054319B discloses an energy-saving and environmentally friendly high and low voltage distribution cabinet, including a box body and a solar panel; the distribution cabinet also includes a stepless adjustment device, and a plurality of stepless adjustment devices are provided. The plurality of stepless adjustment devices are arranged inside the box body along the height direction of the box body, and the adjacent stepless adjustment devices along the height direction of the box body are plugged in and matched, and the upper part of the stepless adjustment device is used to receive electrical components. In the above application document, the two adjacent stepless adjustment devices are adjusted first according to the size of the electrical components to be placed as needed, so that the adjustment component located above and the adjustment component located below slide relative to each other along the height direction of the box body. At this time, the total length formed by the two adjustment components will change, which will be more troublesome when the placed electrical components need to be inspected and removed, which is not conducive to future maintenance work. Summary of the invention
[0004] The present invention provides an energy-saving and environment-friendly high and low voltage distribution cabinet, which solves the problems raised in the above documents.
[0005] The technical solution of the present invention is as follows: an energy-saving and environmentally friendly high and low voltage distribution cabinet, comprising a base, the top of the base is fixedly connected to a cabinet body, the top of the cabinet body is fixedly connected to a top cover, the front end of the cabinet body is provided with a cabinet door, the front end of the cabinet door is fixedly connected to a handle, and the interior of the cabinet body is provided with an automatic pop-up mechanism; the automatic pop-up mechanism comprises a fixed guide rail and a spring telescopic rod, the fixed guide rail is fixedly connected to the interior of the cabinet body, the inner side of the fixed guide rail is slidably connected to a pop-up frame, one end of the spring telescopic rod is fixedly connected to the inner rear wall of the fixed guide rail, the other end of the spring telescopic rod is fixedly connected to the rear end of the cabinet body, a groove is provided at the inner bottom of the fixed guide rail, a telescopic spring is provided inside the groove, and the An arc block is slidably connected to the inside of the groove through a telescopic spring, a pull rod is fixedly connected to the bottom of the arc block, a moving block is fixedly connected to the bottom of the pop-up frame, a card slot is opened at the bottom of the moving block, a reminder mechanism is provided on the top of the fixed guide rail, and a speed control mechanism is provided on the side of the moving block. By providing an automatic pop-up mechanism, the electrical components can be installed and placed through the pop-up frame. When the electrical components need to be inspected and disassembled, the pull rod is pulled downward to make the arc block leave the card slot and retract into the groove. At this time, the pop-up frame will automatically pop out to the front end to facilitate the staff to inspect and disassemble the electrical components. After pushing the pop-up frame back, the arc block will automatically snap into the card slot to limit the pop-up frame, which is more convenient to use as a whole.
[0006] One third of the arc block is located in the slot in the initial state, the spring in the spring telescopic rod is in a compressed state in the initial state, the arc block is stuck in the slot so that the pop-up frame cannot move to the front end, and the spring in the spring telescopic rod can drive the pop-up frame to move to the front end when it rebounds.
[0007] The pull rod penetrates and is slidably connected to the bottom of the fixed guide rail, the depth of the groove is greater than the length of the arc block, and pulling the pull rod downwards can drive the arc block to leave the slot and completely retract into the groove.
[0008] The arc block is made of aluminum alloy, and the arc of the arc block faces the front end of the fixed guide rail. The arc block made of aluminum alloy has high strength and is not easy to rust and damage. When the arc surface of the arc block is squeezed, it will move into the groove.
[0009] The reminder mechanism includes a pneumatic chamber and a bracket, the pneumatic chamber is observed and fixedly connected to the top of the fixed guide rail, one end of the pneumatic chamber is provided with an airbag, the other end of the pneumatic chamber has an internal piston slidably connected to a push rod, the top of the push rod is fixedly connected to a knocking block, one end of the bracket is fixedly connected to the top of the fixed guide rail, and the other end of the bracket is fixedly connected to a bell at the bottom. By providing a reminder mechanism, the ejection frame is pushed back so that the slot and the groove fit together and the arc block can be inserted. The knocking block will be driven to knock the bell through the cooperation of the pneumatic chamber, the airbag and other components, and the knocking block knocks the bell to make a sound to remind the staff that it has been pushed to the appropriate position and the pushing can be stopped, which further improves the overall convenience of use.
[0010] The airbag is initially in conflict with the rear end of the moving block and is in a squeezed state. When the moving block leaves the airbag, the airbag will rebound. At this time, the air pressure in the air pressure chamber returns to the airbag, and the push rod moves downward.
[0011] The knocking block is square in shape as a whole, and the top of the knocking block is in contact with the bell in an initial state, and the push rod moves downward to drive the knocking block to move downward and away from the bell.
[0012] The speed control mechanism includes a connecting frame, which is fixedly connected to the side of the moving block, and a roller is rotatably connected to the inner side of the connecting frame. A groove is opened on the surface of the roller, and a compression spring is arranged on the inner side of the groove. A resistance block is slidably connected to the interior of the groove through the compression spring. By providing a speed control mechanism, when the pop-up frame automatically pops up to the front end, the speed of the pop-up frame automatically popping up to the front end will be slowed down through the cooperation of components such as the roller, the groove, the compression spring, and the resistance block, so as to prevent the pop-up frame from automatically popping up to the front end too fast to generate shock and cause damage to the electrical components thereon, and will not be greatly affected when the pop-up frame is pushed back, thereby improving the overall stability.
[0013] The outer wall of the roller is in contact with the inner wall of the fixed guide rail in the initial state, and the resistance block is completely located in the groove body in the initial state. When the moving block follows the pop-up frame to move, the roller and the inner wall of the fixed guide rail will rub against each other, thereby rotating. When the resistance block is completely in the groove body, it will not affect the movement of the moving block and the pop-up frame.
[0014] The resistance block is made of rubber, and one end of the resistance block away from the compression spring is uneven. When the uneven end of the resistance block made of rubber contacts the inner wall of the fixed guide rail, greater resistance will be generated.
[0015] The working principle and beneficial effects of the present invention are: 1. The present invention is provided with an automatic pop-up mechanism, so that the electrical components can be installed and placed through the pop-up rack. When the electrical components need to be inspected and disassembled, the pull rod is pulled downward to make the arc block leave the card slot and retract into the groove. At this time, the pop-up rack will automatically pop out to the front end to facilitate the staff to inspect and disassemble the electrical components. After the pop-up rack is pushed back, the arc block will automatically snap into the card slot to limit the pop-up rack, which is more convenient to use as a whole.
[0016] 2. The present invention is provided with a reminder mechanism, so that the ejection frame is pushed back so that the card slot and the groove fit together and when the arc block is inserted, the cooperation of the air pressure chamber, the air bag and other components will drive the knocking block to knock on the bell. The knocking block knocks on the bell to make a sound to remind the staff that the push has been pushed to the appropriate position and the pushing can be stopped, which further improves the overall convenience of use.
[0017] 3. The present invention is provided with a speed control mechanism, so that when the pop-up frame automatically pops out to the front end, the speed of the pop-up frame automatically popping out to the front end is slowed down by the cooperation of components such as the roller, the slot body, the compression spring, and the resistance block, so as to prevent the pop-up frame from automatically popping out to the front end too fast and causing shock to damage the electrical components thereon, while the pop-up frame will not be greatly affected when being pushed back, thereby improving the overall stability. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0019] Figure 1 It is a three-dimensional schematic diagram of the overall structure of the present invention; Figure 2 It is a three-dimensional cross-sectional view of the overall structure of the present invention; Figure 3 A three-dimensional schematic diagram of the overall structure of the automatic pop-up mechanism of the present invention; Figure 4 A three-dimensional cross-sectional view of the overall structure of the automatic pop-up mechanism of the present invention; Figure 5 A three-dimensional cross-sectional view of a partial structure of the automatic pop-up mechanism of the present invention; Figure 6 It is a three-dimensional schematic diagram of the structure of the reminder mechanism of the present invention; Figure 7 It is a three-dimensional schematic diagram of the speed control mechanism structure of the present invention; Figure 8 It is a three-dimensional cross-sectional view of the speed control mechanism structure of the present invention.
[0020] In the figure: 1. base; 2. cabinet body; 3. top cover; 4. cabinet door; 5. handle; 6. automatic pop-up mechanism; 61. fixed guide rail; 62. pop-up frame; 63. spring telescopic rod; 64. groove; 65. telescopic spring; 66. arc block; 67. pull rod; 68. moving block; 69. card slot; 7. reminder mechanism; 71. air pressure chamber; 72. air bag; 73. push rod; 74. knocking block; 75. bracket; 76. bell; 8. speed control mechanism; 81. connecting frame; 82. roller; 83. slot; 84. compression spring; 85. resistance block. DETAILED DESCRIPTION
[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0022] Example 1 like Figure 1 to Figure 6As shown, this embodiment proposes an energy-saving and environmentally friendly high and low voltage distribution cabinet, including a base 1, a cabinet body 2 is fixedly connected to the top of the base 1, a top cover 3 is fixedly connected to the top of the cabinet body 2, a cabinet door 4 is arranged at the front end of the cabinet body 2, a handle 5 is fixedly connected to the front end of the cabinet door 4, and an automatic pop-up mechanism 6 is arranged inside the cabinet body 2; the automatic pop-up mechanism 6 includes a fixed guide rail 61 and a spring telescopic rod 63, the fixed guide rail 61 is fixedly connected to the inside of the cabinet body 2, a pop-up frame 62 is slidably connected to the inner side of the fixed guide rail 61, one end of the spring telescopic rod 63 is fixedly connected to the inner rear wall of the fixed guide rail 61, and the spring telescopic rod 63 is fixedly connected to the inner rear wall of the fixed guide rail 61. The other end of the telescopic rod 63 is fixedly connected to the rear end of the cabinet 2. A groove 64 is provided at the inner bottom of the fixed guide rail 61. A telescopic spring 65 is provided inside the groove 64. An arc block 66 is slidably connected inside the groove 64 through the telescopic spring 65. One third of the arc block 66 is located in the card slot 69 in the initial state. The spring in the spring telescopic rod 63 is in a compressed state in the initial state. The arc block 66 is stuck in the card slot 69 so that the pop-up frame 62 cannot move to the front end. When the spring in the spring telescopic rod 63 rebounds, the pop-up frame 62 can be driven to move to the front end. The bottom of the arc block 66 is fixedly connected A pull rod 67 is connected, and the pull rod 67 penetrates and is slidably connected to the bottom of the fixed guide rail 61. The depth of the groove 64 is greater than the length of the arc block 66. Pulling the pull rod 67 downward can drive the arc block 66 to leave the card slot 69 and completely retract into the groove 64. The arc block 66 is made of aluminum alloy, and the arc of the arc block 66 faces the front end of the fixed guide rail 61. The arc block 66 made of aluminum alloy has high strength and is not easy to rust and damage. When the arc surface of the arc block 66 is squeezed, it will move into the groove 64. The bottom of the pop-up frame 62 is fixedly connected with a moving block 68, and a card slot 69 is provided at the bottom of the moving block 68. A reminder mechanism 7 is provided on the top of the fixed guide rail 61, and a speed control mechanism 8 is provided on the side of the moving block 68. By providing an automatic pop-up mechanism 6, the electrical components can be placed through the pop-up rack 62. When the electrical components need to be inspected and disassembled, the pull rod 67 is pulled downward to make the arc block 66 leave the card slot 69 and retract into the groove 64. At this time, the pop-up rack 62 will automatically pop out to the front end to facilitate the staff to inspect and disassemble the electrical components. After the pop-up rack 62 is pushed back, the arc block 66 will automatically snap into the card slot 69 to limit the pop-up rack 62, which is more convenient to use as a whole. The reminding mechanism 7 includes a pneumatic chamber 71 and a bracket 75. The pneumatic chamber 71 is observed and fixedly connected to the top of the fixed guide rail 61. An airbag 72 is arranged at one end of the pneumatic chamber 71. A push rod 73 is slidably connected to the internal piston at the other end of the pneumatic chamber 71. The airbag 72 initially conflicts with the rear end of the moving block 68, and the airbag 72 is in an extruded state in the initial state. When the moving block 68 leaves the airbag 72, the airbag 72 will rebound. At this time, the air pressure in the pneumatic chamber 71 returns to the airbag 72, and the push rod 73 moves downward. The top of the push rod 73 is fixedly connected to a knocking block 74. One end of the bracket 75 is fixedly connected to the top of the fixed guide rail 61, and the other end of the bracket 75 is fixedly connected to the top of the fixed guide rail 61. A bell 76 is fixedly connected to the bottom of one end, and the knocking block 74 is square in shape as a whole, and the top of the knocking block 74 is in contact with the bell 76 in the initial state. The downward movement of the push rod 73 will drive the knocking block 74 to move downward and away from the bell 76. By providing a reminder mechanism 7, the pop-up frame 62 is pushed back so that the slot 69 fits with the groove 64. When the arc block 66 is inserted, the knocking block 74 will be driven to knock on the bell 76 through the cooperation of components such as the air pressure chamber 71 and the air bag 72. The knocking block 74 knocks on the bell 76 to make a sound to remind the staff that it has been pushed to the appropriate position and the pushing can be stopped, which further improves the overall convenience of use.
[0023] In this embodiment, the cabinet door 4 is opened by the handle 5, and the electrical components can be placed on the pop-up rack 62 when being installed. The hollow pop-up rack 62 has high permeability and is convenient for heat dissipation. When the electrical components need to be inspected and disassembled after long-term use, the pull rods 67 on both sides of the bottom of the fixed guide rail 61 are pulled at the same time. Pulling the pull rods 67 downward can drive the arc block 66 to leave the card slot 69 and completely retract into the groove 64. When the arc block 66 leaves the card slot 69, the spring in the spring telescopic rod 63 will rebound and drive the pop-up rack 62 to move to the front end, and the moving block 68 will also move to the front end accordingly, and its bottom card slot 69 and the groove 64 are misaligned. Then, the pull rod 67 is released, and the telescopic spring 65 drives the pull rod 67 and the arc block 66 to restore. The pop-up rack 62 moves to the front end and pops out, which is convenient for the staff to inspect and disassemble the electrical components. When the pop-up rack 62 is pushed back, the moving block 68 will first squeeze the arc surface of the arc block 66. At this time, the arc When the ejection rack 62 is pushed back, the movable block 68 moves toward the rear end, driving the card slot 69 to coincide with the groove 64, and the telescopic spring 65 is compressed. When the movable block 68 moves toward the rear end, driving the card slot 69 to coincide with the groove 64, the telescopic spring 65 rebounds and drives the arc block 66 to snap into the card slot 69. The snapping of the arc block 66 into the card slot 69 will prevent the ejection rack 62 from moving toward the front end and popping out, thereby completing the recovery. The overall use is more convenient and convenient for later maintenance work. When the ejection rack 62 is pushed back, the movable block 68 moves toward the rear end, driving the card slot 69 to coincide with the groove 64, and squeezing the air bag 72. The squeezed air bag 72 will enter the air pressure chamber 71 to push the push rod 73 to move upward. The upward movement of the push rod 73 will drive the knocking block 74 to move upward and knock on the bell 76. The knocking block 74 knocks on the bell 76 to make a sound to remind the staff that the push has been pushed to the appropriate position and the push can be stopped, further improving the overall convenience of use.
[0024] Example 2 like Figure 1 to Figure 8As shown, based on the same concept as the above-mentioned embodiment 1, a second embodiment is also proposed, the speed control mechanism 8 includes a connecting frame 81, the connecting frame 81 is fixedly connected to the side of the moving block 68, the inner side of the connecting frame 81 is rotatably connected to a roller 82, the surface of the roller 82 is provided with a groove body 83, the inner side of the groove body 83 is provided with a compression spring 84, the interior of the groove body 83 is slidably connected to a resistance block 85 through the compression spring 84, the outer side wall of the roller 82 is in contact with the inner side wall of the fixed guide rail 61 in the initial state, the resistance block 85 is completely located in the groove body 83 in the initial state, when the moving block 68 moves following the pop-up frame 62, the roller 82 will rub against the inner side wall of the fixed guide rail 61, thereby rotating, and the resistance block 85 is completely in the groove body 8 3, it will not affect the movement of the moving block 68 and the pop-up frame 62. The material of the resistance block 85 is rubber. The end of the resistance block 85 away from the compression spring 84 is uneven. When the uneven end of the rubber resistance block 85 contacts the inner wall of the fixed guide rail 61, it will generate greater resistance. By providing the speed control mechanism 8, when the pop-up frame 62 automatically pops out to the front end, the speed of the pop-up frame 62 automatically popping out to the front end will be slowed down by the cooperation of the roller 82, the groove body 83, the compression spring 84, the resistance block 85 and other components, so as to prevent the pop-up frame 62 from automatically popping out to the front end too fast to generate shock and cause damage to the electrical components thereon, and will not be greatly affected when pushing the pop-up frame 62 back, thereby improving the overall stability.
[0025] In this embodiment, when the moving block 68 moves with the pop-up frame 62, the roller 82 will rub against the inner wall of the fixed guide rail 61 and rotate. When the pop-up frame 62 is pushed back, the speed is slow, so that the roller 82 will also rotate slowly. At this time, the resistance block 85 is completely in the groove body 83 and will not affect the movement of the moving block 68 and the pop-up frame 62. When the pop-up frame 62 pops out to the front end, the speed is fast, and the roller 82 rotates faster. The centrifugal force generated by the rapid rotation of the roller 82 will throw the resistance block 85 out. At this time, the uneven end of the rubber resistance block 85 contacts the inner wall of the fixed guide rail 61, which will generate greater resistance and slow down the speed of the pop-up frame 62 when it pops out to the front end, preventing the pop-up frame 62 from automatically popping out to the front end at a too fast speed to generate vibrations and cause damage to its electrical components, thereby improving the overall stability.
[0026] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. An energy-saving and environmentally friendly high and low voltage distribution cabinet, characterized in that: The cabinet comprises a base (1), the top of the base (1) is fixedly connected to a cabinet body (2), the top of the cabinet body (2) is fixedly connected to a top cover (3), the front end of the cabinet body (2) is provided with a cabinet door (4), the front end of the cabinet door (4) is fixedly connected to a handle (5), and the interior of the cabinet body (2) is provided with an automatic pop-up mechanism (6); The automatic pop-up mechanism (6) comprises a fixed guide rail (61) and a spring telescopic rod (63); the fixed guide rail (61) is fixedly connected to the interior of the cabinet (2); a pop-up frame (62) is slidably connected to the inner side of the fixed guide rail (61); one end of the spring telescopic rod (63) is fixedly connected to the inner rear wall of the fixed guide rail (61); the other end of the spring telescopic rod (63) is fixedly connected to the rear end of the cabinet (2); a groove (64) is provided at the inner bottom of the fixed guide rail (61); the groove A telescopic spring (65) is arranged inside the (64), an arc block (66) is slidably connected to the inside of the groove (64) via the telescopic spring (65), a pull rod (67) is fixedly connected to the bottom of the arc block (66), a moving block (68) is fixedly connected to the bottom of the pop-up frame (62), a card slot (69) is provided at the bottom of the moving block (68), a reminder mechanism (7) is arranged on the top of the fixed guide rail (61), and a speed control mechanism (8) is arranged on the side of the moving block (68).
2. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 1 is characterized in that: In the initial state, one third of the arc block (66) is located in the clamping groove (69), and the spring in the spring telescopic rod (63) is in a compressed state in the initial state.
3. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 2 is characterized in that: The pull rod (67) penetrates the bottom of the fixed guide rail (61) and is slidably connected thereto, and the depth of the groove (64) is greater than the length of the arc block (66).
4. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 3 is characterized in that: The material of the arc block (66) is an aluminum alloy material, and the arc of the arc block (66) faces the front end of the fixed guide rail (61).
5. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 4 is characterized in that: The reminder mechanism (7) comprises an air pressure chamber (71) and a bracket (75), wherein the air pressure chamber (71) is observed and fixedly connected to the top of the fixed guide rail (61), an air bag (72) is arranged at one end of the air pressure chamber (71), a push rod (73) is slidably connected to the internal piston at the other end of the air pressure chamber (71), a knocking block (74) is fixedly connected to the top of the push rod (73), one end of the bracket (75) is fixedly connected to the top of the fixed guide rail (61), and a bell (76) is fixedly connected to the bottom of the other end of the bracket (75).
6. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 5 is characterized in that: In an initial state, the airbag (72) abuts against the rear end of the moving block (68), and in an initial state, the airbag (72) is in a squeezed state.
7. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 6 is characterized in that: The knocking block (74) is square in shape as a whole, and the top of the knocking block (74) is in contact with the bell (76) in an initial state.
8. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 7 is characterized in that: The speed control mechanism (8) comprises a connecting frame (81), the connecting frame (81) being fixedly connected to a side surface of the moving block (68), a roller (82) being rotatably connected to the inner side of the connecting frame (81), a groove (83) being provided on the surface of the roller (82), a compression spring (84) being provided on the inner side of the groove (83), and a resistance block (85) being slidably connected to the interior of the groove (83) via the compression spring (84).
9. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 8 is characterized in that: In an initial state, the outer side wall of the roller (82) contacts the inner side wall of the fixed guide rail (61), and in an initial state, the resistance block (85) is completely located in the groove body (83).
10. The energy-saving and environmentally friendly high and low voltage distribution cabinet according to claim 9, characterized in that: The resistance block (85) is made of rubber, and one end of the resistance block (85) away from the compression spring (84) is uneven.
Citation Information
Patent Citations
An energy-saving and environmentally friendly high and low voltage distribution cabinet
CN118054319B