A PCB circuit board detection device

Abstract

The present invention relates to the technical field of circuit detection equipment, and particularly relates to a PCB circuit board detection device. The technical problem is that when the current detection device detects a PCB circuit board, the operation is not convenient enough, resulting in low detection efficiency, and the detection is not stable and accurate enough, thus leading to poor detection effects. A PCB circuit board detection device includes an outer frame, a limiting plate, a rotating rod, etc.; a limiting plate is fixedly connected inside the outer frame, and rotating rods are rotatably connected to both sides of the bottom of the limiting plate. It can automatically switch between the positive test frame and the negative test frame, and at the same time automatically flip the PCB circuit board, thereby making the operation of the staff more convenient, improving the detection efficiency. The compression spring presses the positive test frame and the negative test frame through the rotating plate, so that the probes of the positive test frame and the negative test frame are in full contact with the test points on the front and back sides of the PCB circuit board, making the detection more thorough.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit detection equipment, and particularly relates to a PCB circuit board detection device. Background Art

[0002] The detection of PCB circuit boards is often the last step after the production of PCB circuit boards. The PCB circuit boards usually have test points on both sides. The detection of PCB circuit boards is mostly divided into "flying probe testing" and "test fixture testing". "Flying probe testing" is mostly applied to the sample board detection of PCB circuit boards, while "test fixture testing" is mostly used in the detection of mass-produced PCB circuit boards. In "test fixture testing", the staff needs to prepare a front test fixture and a back test fixture to detect the front and back sides of the PCB circuit board respectively. During the detection process, the staff often first uses the front test fixture to detect the front side of the manually positioned PCB circuit board, and then the staff manually flips and positions the PCB circuit board, and then switches to the back test fixture to detect the back side of the PCB board.

[0003] Since manually flipping and positioning the PCB circuit board consumes a large amount of labor costs and takes a long time, and the current detection device is not convenient for automatically positioning the PCB circuit board before each detection and automatically flipping the PCB circuit board after each detection, which is not convenient for the staff to use, resulting in low detection efficiency of the PCB circuit board. Moreover, dust is easily attached to the surface of the PCB circuit board and it is easy to shift during the detection process. The existing detection device is not convenient for clamping the positioned PCB circuit board during the detection, resulting in unstable detection of the PCB circuit board, and it is not convenient to clean the dust on the surface of the PCB circuit board before each detection, resulting in inaccurate detection, thus leading to poor detection results. Summary of the Invention

[0004] In order to overcome the above-mentioned drawbacks, the present invention provides a PCB circuit board detection device, which can automatically flip and position the PCB circuit board to make the operation of the staff more convenient and improve the detection efficiency, and can clean the surface of the PCB circuit board before detection and clamp the PCB circuit board during detection to make the detection of the circuit board more stable and accurate, thereby enhancing the detection effect of the PCB circuit board.

[0005] The technical solution of the present invention is: a PCB circuit board detection device, including an outer frame, a limiting plate, a rotating rod, a torsion spring, a support plate, a PCB circuit board, an electric push rod, a detection mechanism, a flipping mechanism, an opening and closing mechanism, a positive test rack and a negative test rack. An inlet is opened on the outer frame. A limiting plate is fixedly connected inside the outer frame. Both sides of the bottom of the limiting plate are rotatably connected with rotating rods. The two rotating rods are symmetrically arranged. Torsion springs are connected between the two ends of the mutually remote sides of the two rotating rods and the limiting plate. There are a total of four torsion springs. Support plates are fixedly connected to the mutually close sides of the two rotating rods. The two support plates are symmetrically arranged. A PCB circuit board is placed between the tops of the two support plates. A number of test points are provided on both the upper and lower sides of the PCB circuit board. Electric push rods are installed on both sides of the top of the outer frame. A detection mechanism for detecting the front and back sides of the PCB circuit board is provided on the electric push rod. A positive test rack for detecting the front side of the PCB circuit board and a negative test rack for detecting the back side of the PCB circuit board are provided on the detection mechanism. A flipping mechanism for flipping the PCB circuit board is provided on the detection mechanism. An opening and closing mechanism for opening and closing the support plate is provided on the flipping mechanism.

[0006] Further, the detection mechanism includes a support frame, a compression spring, a friction block, a rotating plate, an extrusion column, a limiting block, an overrunning clutch one and an extrusion ring. The support frame is slidably connected between the bottoms of the telescopic rods of the two electric push rods. Compression springs are connected between the two sides of the support frame and the telescopic rods of the two electric push rods respectively. Two friction blocks are installed on the support frame. The two friction blocks are symmetrically arranged. A rotating plate is rotatably connected to the support frame. The rotating plate is perpendicular to the support frame. The top side of the rotating plate is a spline groove structure. Both friction blocks are in contact with the spline groove structure of the rotating plate. A positive test rack and a negative test rack are respectively installed on the two bottom sides of the rotating plate. Among them, the positive test rack is located directly above the PCB circuit board. An extrusion column is fixedly connected to the top of the rotating plate. Two extrusion grooves are evenly spaced on the side of the extrusion column. A limiting block is fixedly connected to the limiting plate. An overrunning clutch one is installed inside the limiting block. An extrusion ring is installed inside the overrunning clutch one. The extrusion ring is sleeved on the extrusion column. Two columnar protrusions are evenly spaced on the inner side of the extrusion ring. The two columnar protrusions of the extrusion ring are respectively located in the two extrusion grooves.

[0007] Further, a number of probes are provided on both the positive test rack and the negative test rack. The number of probes on the positive test rack respectively correspond to the number of test points on the front side of the PCB circuit board. The number of probes on the negative test rack respectively correspond to the number of test points on the back side of the PCB circuit board.

[0008] Further, the extrusion groove is composed of a vertical groove and a threaded groove. The vertical groove and the threaded groove of the extrusion groove are communicated. The vertical groove of the extrusion groove is located above the threaded groove of the extrusion groove. The two columnar protrusions of the extrusion ring are respectively located at the bottoms of the threaded grooves of the two extrusion grooves.

[0009] Further, the flipping mechanism includes a moving rod, a U-shaped rod, a limiting sleeve, a sliding column, a rhombic rod, a first tension spring, a second overrunning clutch, a flipping rod, a sliding block, a reset spring, a sliding ring, and a sliding rod. The moving rod is fixedly connected to the support frame. Two U-shaped rods are fixedly connected to both sides of the moving rod. Four U-shaped rods are each provided with a U-shaped groove. The two U-shaped rods on the same side form a group, and the two groups of U-shaped rods are symmetrically arranged. The two U-shaped rods in the same group are symmetrically arranged. Limiting sleeves are fixedly connected to both sides of the limiting plate. The two limiting sleeves are symmetrically arranged. Two flipping grooves are opened on each of the two limiting sleeves. A sliding column is slidably connected to the side of the two limiting sleeves close to each other. A rhombic rod is slidably connected to the side of the two sliding columns close to each other. A first tension spring is connected between the two rhombic rods and the two sliding columns respectively. The ends of the two rhombic rods close to each other are each provided with a frosted surface. A second overrunning clutch is installed on each of the ends of the two rhombic rods close to each other. Flipping rods are installed on the outer sides of the two second overrunning clutches. The ends of the two flipping rods away from each other are also provided with frosted surfaces. The frosted surfaces of the two flipping rods are in contact with the frosted surfaces of the two rhombic rods respectively. Slots are opened on the sides of the two flipping rods close to each other. The two slots correspond to both sides of the PCB circuit board respectively. Sliding blocks are slidably connected to the upper and lower sides of the two sliding columns. There are four sliding blocks in total. The two sliding blocks on the same sliding column pass through the two flipping grooves on the same limiting sleeve respectively. A reset spring is connected between each of the two sliding blocks on the same sliding column and the same sliding column respectively. There are four reset springs in total. Sliding rings are sleeved on the two limiting sleeves. The parts of the two sliding blocks on the same sliding column exposed outside the limiting sleeve are located within the sliding rings on the same limiting sleeve. Sliding rods are fixedly connected to both sides of the two sliding rings. The four sliding rods are all slidably connected to the limiting plate. The two sliding rods on the same sliding ring form a group, and the two groups of sliding rods are symmetrically arranged. The two sliding rods in the same group are symmetrically arranged. The ends of the two groups of sliding rods away from each other are located within the U-shaped grooves of the two groups of U-shaped rods respectively.

[0010] Further, the opening and closing mechanism includes a pressing rod, a second tension spring, and a pressing block. The four pressing rods are respectively slidably connected to the four sliding rods. The four pressing rods are all located below the limiting plate. The two pressing rods on the same side form a group, and the two groups of pressing rods are symmetrically arranged. The two pressing rods in the same group are symmetrically arranged. A second tension spring is connected between each of the four pressing rods and the four sliding rods respectively. Pressing blocks are fixedly connected to both ends of the sides of the two rotating rods away from each other. The two pressing blocks on the same rotating rod form a group, and the two groups of pressing blocks are symmetrically arranged. The two pressing blocks in the same group are symmetrically arranged.

[0011] Further, strip-shaped protrusions are provided at the bottoms of the four pressing rods.

[0012] Further, inclined surfaces are provided on the sides of the two groups of pressing blocks close to each other, and straight surfaces are provided on the sides of the two groups of pressing blocks away from each other.

[0013] Further, a positioning mechanism is further included. The positioning mechanism is arranged on the support plate and is used to position the PCB circuit board before each detection. The positioning mechanism includes a rotating shaft, a gear, a positioning rod, a third tension spring, a rack and an extrusion frame. The two rotating shafts are respectively rotatably connected to the bottoms of the two support plates. Gears are fixedly connected to the two rotating shafts. The two gears are respectively located below the two support plates. The two sides of the two support plates are both slidably connected with positioning rods. The two positioning rods on the same support plate form a group. The two groups of positioning rods are symmetrically arranged. The two positioning rods in the same group are symmetrically arranged. The sides of the two groups of positioning rods away from each other respectively contact the two sides of the two flipping rods. Tension springs three are connected between the two groups of positioning rods and the two support plates respectively. There are four tension springs three in total. Racks are fixedly connected to the bottoms of the four positioning rods. The two racks on the same support plate are symmetrically arranged on both sides of the gear on the same support plate. The two racks on the same support plate are both meshed with the gear on the same support plate. An extrusion frame is rotatably connected to the bottom of the rotating plate. The two sides of the extrusion frame are respectively slidably connected with the two sides of the limiting plate. The bottom of the extrusion frame is obliquely arranged.

[0014] Further, a cleaning mechanism is further included. The cleaning mechanism is arranged on the limiting plate and is used to blow off the dust on the test surface of the PCB circuit board before each test. The cleaning mechanism includes a blower group, a cross tube, an air outlet head, a fourth tension spring and a pressure-bearing frame. The two blower groups are respectively installed on the lower sides of the two sides of the limiting plate. Cross tubes are communicated with the two blower groups. Air outlet heads are slidably connected to the two cross tubes. The two air outlet heads are symmetrically arranged. The two air outlet heads are respectively communicated with the two cross tubes. Air outlets are opened at the ends of the two air outlet heads close to each other. The air outlets of the two air outlet heads are both aligned with the top surface of the PCB circuit board. Tension springs four are connected between the two air outlet heads and the two cross tubes respectively. Pressure-bearing frames are fixedly connected to the two air outlet heads. The sides of the two pressure-bearing frames away from each other respectively contact the sides of the two groups of return-shaped rods close to each other.

[0015] The beneficial effects are as follows: 1. After the front test points of the PCB circuit board are detected in the present invention, the positive test frame and the negative test frame will be switched immediately. At the same time, the two support plates are rotated, and the PCB circuit board is automatically flipped so that the reverse test points of the PCB circuit board correspond to the probes of the negative test frame. After the PCB circuit board is flipped, the two support plates support the PCB circuit board again, thereby making the operation of the staff more convenient, improving the detection efficiency, and the compression spring presses the positive test frame and the negative test frame through the rotating plate, so that the probes of the positive test frame and the negative test frame are in full contact with the front and back test points of the PCB circuit board, and thus the detection is more sufficient.

[0016] 2. During the detection, the rotating plate moves downward to drive the extrusion frame downward. The downward movement of the extrusion frame causes the four positioning rods to move simultaneously towards the PCB circuit board, thereby positioning and clamping both sides of the PCB circuit board. When the four positioning rods move, they will respectively squeeze the two sides of the two flipping rods, causing the two card slots to catch and position and clamp the other two sides of the PCB circuit board, thus saving the time for manual positioning by the staff, further improving the detection efficiency, and making the detection of the PCB circuit board more stable, thereby enhancing the detection effect of the PCB circuit board.

[0017] 3. Before detecting the PCB circuit board, when the return-shaped rod moves downward, it will squeeze the two pressure-receiving frames to drive the two air outlets to move towards each other. When the two air outlets move, they no longer block the cross-shaped tube, and the air inhaled by the air blower group will be input into the air outlets through the cross-shaped tube. The movement of the air outlets will evenly blow the air inside through the air outlet of the air outlet towards the surface of the PCB circuit board, thereby cleaning the surface of the PCB circuit board before detection, making the detection of the PCB circuit board more accurate, and further enhancing the detection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the present invention.

[0019] Figure 2 It is a sectional three-dimensional structural schematic diagram of the present invention.

[0020] Figure 3 It is a partial sectional three-dimensional structural schematic diagram of the present invention.

[0021] Figure 4 It is a partial three-dimensional structural schematic diagram of the present invention.

[0022] Figure 5 It is a split three-dimensional structural schematic diagram of the detection mechanism of the present invention.

[0023] Figure 6 It is a partial sectional three-dimensional structural schematic diagram of the detection mechanism of the present invention.

[0024] Figure 7 It is a partial three-dimensional structural schematic diagram of the flipping mechanism and the cleaning mechanism of the present invention.

[0025] Figure 8 It is a partial three-dimensional structural schematic diagram of the flipping mechanism of the present invention.

[0026] Figure 9 It is a partial sectional three-dimensional structural schematic diagram of the flipping mechanism of the present invention.

[0027] Figure 10 It is a sectional three-dimensional structural schematic diagram of the rhombic rod, the flipping rod and the overrunning clutch II of the present invention.

[0028] Figure 11 This is a partial three-dimensional structural schematic diagram of the return rod and the sliding rod of the present invention.

[0029] Figure 12 For the present invention Figure 4 The enlarged three-dimensional structural schematic diagram of A in it.

[0030] Figure 13 For the present invention Figure 4 The enlarged three-dimensional structural schematic diagram of B in it.

[0031] Figure 14 This is a partial sectional three-dimensional structural schematic diagram of the positioning mechanism of the present invention.

[0032] Figure 15 This is a partial three-dimensional structural schematic diagram of the positioning mechanism, the flipping mechanism and the PCB circuit board of the present invention.

[0033] Figure 16 This is a partial sectional three-dimensional structural schematic diagram of the positioning mechanism and the support plate of the present invention.

[0034] Figure 17 This is a partial sectional three-dimensional structural schematic diagram of the positioning rod, the rack and the support plate of the present invention.

[0035] Figure 18 This is a partial three-dimensional structural schematic diagram of the cleaning mechanism and the return rod of the present invention.

[0036] Figure 19 This is a partial sectional three-dimensional structural schematic diagram of the cleaning mechanism of the present invention.

[0037] Names and serial numbers of components in the figure: 1 - outer frame, 11 - feeding port, 2 - limiting plate, 21 - rotating rod, 22 - torsion spring, 23 - support plate, 3 - PCB circuit board, 4 - electric push rod, 51 - support frame, 52 - compression spring, 53 - friction block, 54 - rotating plate, 55 - extrusion column, 551 - extrusion groove, 56 - limiting block, 57 - overrunning clutch one, 58 - extrusion ring, 61 - positive test frame, 62 - negative test frame, 71 - moving rod, 72 - return rod, 721 - return groove, 73 - limiting sleeve, 731 - flipping groove, 74 - sliding column, 75 - rhombic rod, 76 - tension spring one, 77 - overrunning clutch two, 78 - flipping rod, 781 - clamping groove, 79 - sliding block, 710 - return spring, 711 - sliding ring, 712 - sliding rod, 81 - extrusion rod, 82 - tension spring two, 83 - extrusion block, 91 - rotating shaft, 92 - gear, 93 - positioning rod, 94 - tension spring three, 95 - rack, 96 - extrusion frame, 10 - cleaning mechanism, 101 - fan group, 102 - cross tube, 103 - air outlet head, 104 - tension spring four, 105 - pressure receiving frame. Detailed Embodiments

[0038] The preferred technical solutions of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] Embodiment 1: A PCB circuit board detection device, as Figures 1 - 19 shown, includes an outer frame 1, a limiting plate 2, a rotating rod 21, a torsion spring 22, a support plate 23, a PCB circuit board 3, an electric push rod 4, a detection mechanism, a flipping mechanism, an opening and closing mechanism, a positive test rack 61 and a negative test rack 62. An inlet 11 is opened on the outer frame 1. The limiting plate 2 is welded inside the outer frame 1. Rotating rods 21 are rotatably connected to both sides of the bottom of the limiting plate 2. The two rotating rods 21 are symmetrically arranged. Torsion springs 22 are connected between the two ends of the mutually remote sides of the two rotating rods 21 and the limiting plate 2. There are four torsion springs 22 in total. Support plates 23 are welded on the mutually close sides of the two rotating rods 21. The two support plates 23 are symmetrically arranged. A PCB circuit board 3 is placed between the tops of the two support plates 23. A plurality of test points are provided on both the upper and lower sides of the PCB circuit board 3. Electric push rods 4 are installed on both sides of the top of the outer frame 1. A detection mechanism for detecting the front and back sides of the PCB circuit board 3 is provided on the electric push rod 4. A positive test rack 61 for detecting the front side of the PCB circuit board 3 and a negative test rack 62 for detecting the back side of the PCB circuit board 3 are provided on the detection mechanism. A flipping mechanism for flipping the PCB circuit board 3 is provided on the detection mechanism. An opening and closing mechanism for opening and closing the support plate 23 is provided on the flipping mechanism.

[0040] The detection mechanism includes a support frame 51, a compression spring 52, a friction block 53, a rotating plate 54, an extrusion column 55, a limiting block 56, an overrunning clutch I 57 and an extrusion ring 58. The support frame 51 is slidably connected between the bottoms of the telescopic rods of the two electric push rods 4. Compression springs 52 are connected between the two sides of the support frame 51 and the telescopic rods of the two electric push rods 4 respectively. Two friction blocks 53 are installed on the support frame 51, and the two friction blocks 53 are symmetrically arranged. A rotating plate 54 is rotatably connected to the support frame 51, and the rotating plate 54 is perpendicular to the support frame 51. The top side of the rotating plate 54 is a spline groove structure, and both friction blocks 53 are in contact with the spline groove structure of the rotating plate 54. The frictional force between the friction block 53 and the spline groove structure of the rotating plate 54 is used to prevent the rotating plate 54 from rotating too large an angle due to inertia. A positive test frame 61 and a negative test frame 62 are respectively installed at the bottom of both sides of the rotating plate 54. Among them, the positive test frame 61 is located directly above the PCB board 3. The positive test frame 61 and the negative test frame 62 are respectively used to detect the front and back sides of the PCB board 3. An extrusion column 55 is welded to the top of the rotating plate 54. Two extrusion grooves 551 are evenly spaced on the side of the extrusion column 55. A limiting block 56 is welded to the limiting plate 2. An overrunning clutch I 57 is installed inside the limiting block 56. An extrusion ring 58 is installed inside the overrunning clutch I 57. The extrusion ring 58 is sleeved on the extrusion column 55. Two columnar protrusions are evenly spaced inside the extrusion ring 58. The two columnar protrusions of the extrusion ring 58 are respectively located in the two extrusion grooves 551.

[0041] A number of probes are provided on both the positive test frame 61 and the negative test frame 62. The number of probes on the positive test frame 61 respectively correspond to a number of test points on the front side of the PCB board 3, and the number of probes on the negative test frame 62 respectively correspond to a number of test points on the back side of the PCB board 3. The number of probes on the positive test frame 61 and the negative test frame 62 are respectively used to detect a number of test points on the front and back sides of the PCB board 3.

[0042] The extrusion groove 551 is composed of a vertical groove and a threaded groove. The vertical groove and the threaded groove of the extrusion groove 551 are communicated. The vertical groove of the extrusion groove 551 is located above the threaded groove of the extrusion groove 551. The two columnar protrusions of the extrusion ring 58 are respectively located at the bottoms of the threaded grooves of the two extrusion grooves 551. The threaded groove of the extrusion groove 551 is used to extrude the two columnar protrusions of the extrusion ring 58.

[0043] The flipping mechanism includes a moving rod 71, a looped rod 72, a limiting sleeve 73, a sliding column 74, a rhombic rod 75, a first tension spring 76, an overrunning clutch two 77, a flipping rod 78, a sliding block 79, a return spring 710, a sliding ring 711, and a sliding rod 712. The moving rod 71 is welded to the support frame 51. Two looped rods 72 are welded to both sides of the moving rod 71. A looped groove 721 is formed in each of the four looped rods 72. The two looped rods 72 on the same side form a group, and the two groups of looped rods 72 are symmetrically arranged. The two looped rods 72 in the same group are symmetrically arranged. Limiting sleeves 73 are welded to both sides of the limiting plate 2. The two limiting sleeves 73 are symmetrically arranged. Two flipping grooves 731 are formed in each of the two limiting sleeves 73. A sliding column 74 is slidably connected to the side of each of the two limiting sleeves 73 that is close to the other. A rhombic rod 75 is slidably connected to the side of each of the two sliding columns 74 that is close to the other. A first tension spring 76 is connected between each of the two rhombic rods 75 and the corresponding sliding column 74. A frosted surface is provided at each of the ends of the two rhombic rods 75 that are close to each other. An overrunning clutch two 77 is installed at each of the ends of the two rhombic rods 75 that are close to each other. Flipping rods 78 are installed on the outer sides of the two overrunning clutches two 77. Frosted surfaces are also provided at the ends of the two flipping rods 78 that are away from each other. The frosted surfaces of the two flipping rods 78 are in contact with the frosted surfaces of the two rhombic rods 75 respectively. A card slot 781 is formed in each of the sides of the two flipping rods 78 that are close to each other. The two card slots 781 correspond to both sides of the PCB circuit board 3 respectively. Sliding blocks 79 are slidably connected to the upper and lower sides of each of the two sliding columns 74. There are four sliding blocks 79 in total. The two sliding blocks 79 on the same sliding column 74 pass through the two flipping grooves 731 on the same limiting sleeve 73 respectively. The flipping groove 731 is used to squeeze the sliding block 79 to rotate for flipping. A return spring 710 is connected between each of the two sliding blocks 79 on the same sliding column 74 and the corresponding sliding column 74. There are four return springs 710 in total. Sliding rings 711 are sleeved on each of the two limiting sleeves 73. The parts of the two sliding blocks 79 on the same sliding column 74 that protrude from the limiting sleeve 73 are located within the sliding rings 711 on the same limiting sleeve 73. The sliding ring 711 is used to squeeze the sliding block 79 to move. Sliding rods 712 are welded to both sides of each of the two sliding rings 711. All four sliding rods 712 are slidably connected to the limiting plate 2. The two sliding rods 712 on the same sliding ring 711 form a group, and the two groups of sliding rods 712 are symmetrically arranged. The two sliding rods 712 in the same group are symmetrically arranged. The ends of the two groups of sliding rods 712 that are away from each other are respectively located within the looped grooves 721 of the two groups of looped rods 72. The looped groove 721 is used to squeeze the sliding rod 712 to move.

[0044] The opening and closing mechanism includes a pressing rod 81, a second tension spring 82 and a pressing block 83. The four pressing rods 81 are respectively slidably connected to the four sliding rods 712. The four pressing rods 81 are all located below the limiting plate 2. Two pressing rods 81 on the same side form a group, and the two groups of pressing rods 81 are symmetrically arranged. The two pressing rods 81 in the same group are symmetrically arranged. A second tension spring 82 is connected between the four pressing rods 81 and the four sliding rods 712 respectively. At both ends of the mutually remote sides of the two rotating rods 21, pressing blocks 83 are welded. The two pressing blocks 83 on the same rotating rod 21 form a group, and the two groups of pressing blocks 83 are symmetrically arranged. The two pressing blocks 83 in the same group are symmetrically arranged.

[0045] Strip-shaped protrusions are provided at the bottoms of the four pressing rods 81.

[0046] On the mutually approaching sides of the two groups of pressing blocks 83, inclined surfaces are provided. The inclined surfaces of the pressing blocks 83 are used to press the strip-shaped protrusions of the pressing rods 81. On the mutually remote sides of the two groups of pressing blocks 83, straight surfaces are provided. The strip-shaped protrusions of the pressing rods 81 are used to press the straight surfaces of the pressing blocks 83.

[0047] First, the staff places the PCB circuit board 3 face up between the tops of two support plates 23 through the feeding port 11, aligning several test points on the front of the PCB circuit board 3 with several probes of the positive test frame 61. Subsequently, the staff controls the telescopic rods of the two electric push rods 4 to extend. The extension of the telescopic rods of the two electric push rods 4 will drive the support frame 51, the rotating plate 54, the extrusion column 55, the positive test frame 61, and the negative test frame 62 to move downward together. Under the action of the overrunning clutch one 57, the thread groove of the extrusion groove 551 moving downward will squeeze the columnar protrusion of the extrusion ring 58, causing the extrusion ring 58 to rotate idly by 180 degrees. Subsequently, the columnar protrusion of the extrusion ring 58 will enter the vertical groove of the extrusion groove 551, and thus no longer squeeze the columnar protrusion of the extrusion ring 58. The positive test frame 61 continues to move downward and will contact the front of the PCB circuit board 3, so that several probes of the positive test frame 61 contact several test points on the front of the PCB circuit board 3. The several probes of the positive test frame 61 will feedback the data of the test points on the front of the PCB circuit board 3, thereby detecting the front of the PCB circuit board 3. The telescopic rod of the electric push rod 4 continues to extend to squeeze the compression spring 52, so that the support frame 51 presses on the positive test frame 61 through the rotating plate 54, thereby enabling the probes of the positive test frame 61 to fully contact the test points on the front of the PCB circuit board 3, and thus making the detection more sufficient. After the front of the PCB circuit board 3 is tested, the staff controls the telescopic rod of the electric push rod 4 to retract. The retraction of the telescopic rod of the electric push rod 4 will drive the support frame 51, the rotating plate 54, the extrusion column 55, the positive test frame 61, and the negative test frame 62 to reset upward together. The compression spring 52 resets and no longer presses on the positive test frame 61. Immediately afterwards, the positive test frame 61 resets upward and disengages from the PCB circuit board 3, and thus no longer detects the front of the PCB circuit board 3. Before the extrusion column 55 is fully reset, the columnar protrusion of the extrusion ring 58 will enter the thread groove of the extrusion groove 551 again. Under the action of the overrunning clutch one 57 and the limit block 56, the columnar protrusion of the extrusion ring 58 will squeeze the thread groove, causing the extrusion column 55 to rotate by 180 degrees. The rotation of the extrusion column 55 by 180 degrees will drive the rotating plate 54 to rotate by 180 degrees. Under the action of the spline groove mechanism of the friction block 53 and the rotating plate 54, the rotating plate 54 will not rotate by a larger angle due to inertia. The rotation of the rotating plate 54 by 180 degrees will cause the positive test frame 61 and the negative test frame 62 to rotate and switch positions, so that the negative test frame 62 rotates to directly above the PCB circuit board 3;

[0048] At first, due to the effect of the frosted surfaces of the rhombic rod 75 and the flipping rod 78, it is not easy for the flipping rod 78 to rotate on its own on the rhombic rod 75. While the support frame 51 moves downward, it will drive the moving rod 71 and the looped rod 72 to move downward together. When the looped rod 72 moves to the lowest position, the looped groove 721 will squeeze the sliding rod 712 to move a small distance in the direction closer to the PCB board 3. The sliding rod 712 moving a small distance will, through the sliding ring 711, squeeze the sliding block 79, the reset spring 710, the sliding column 74, the first tension spring 76, the rhombic rod 75, the overrunning clutch two 77, the flipping rod 78, and the extrusion rod 81 to move a small distance together. After the front side of the PCB board 3 is tested, the support frame 51 drives the moving rod 71 and the looped rod 72 to move upward and reset together. After the looped rod 72 moves upward a certain distance, the looped groove 721 will continue to squeeze the sliding rod 712 to move in the direction closer to the PCB board 3. The sliding rod 712 moves and squeezes the sliding block 79 through the sliding ring 711, so that the card slots 781 of the two flipping rods 78 are respectively stuck on both sides of the PCB board 3. At the same time, the sliding rod 712 moves to drive the extrusion rod 81 to move. The strip-shaped protrusion of the extrusion rod 81 will contact the straight surface of the extrusion block 83. After the card slot 781 catches the PCB board 3, immediately the sliding rod 712 drives the extrusion rod 81 and the sliding block 79 to continue moving a small distance. The reset spring 710 is slightly compressed. The strip-shaped protrusion of the extrusion rod 81 will squeeze the straight surface of the extrusion block 83 to make the extrusion block 83 rotate 90 degrees. The extrusion block 83 rotating 90 degrees will drive the support rod and the support plate 23 to rotate 90 degrees together. The torsion spring 22 is twisted. The two support plates 23 will rotate in opposite directions and no longer support the bottom of the PCB board 3. Under the action of the card slot 781, the PCB board 3 remains in place. Immediately, the sliding block 79 continues to move, and the reset spring 710 is continuously compressed. The flipping groove 731 will squeeze the moving sliding block 79 to rotate 180 degrees. The sliding block 79 rotating 180 degrees will drive the sliding column 74 and the rhombic rod 75 to rotate 180 degrees together. The rhombic rod 75 rotating 180 degrees will drive the flipping rod 78 to rotate 180 degrees through the overrunning clutch two 77. The flipping rod 78 will drive the PCB board 3 to flip 180 degrees through the card slot 781, making the back side of the PCB board 3 face upward. Since before flipping the PCB board 3, the positive test frame 61 is in a state of being reset a certain distance, and at the same time the support plate 23 is in a rotated state, thus when the PCB board 3 flips, it will not contact other factors and be stuck. Subsequently, the sliding rod 712 continues to move a small distance to drive the extrusion rod 81 to move a small distance. The strip-shaped protrusion of the extrusion rod 81 no longer squeezes the straight surface of the extrusion block 83. The torsion spring 22 resets to drive the two support plates 23 to reset and contact and support the bottom of the PCB board 3 again. Then the looped rod 72 continues to move upward, and the looped groove 721 will squeeze the sliding rod 712 to move away from the PCB board 3.When the sliding rod 712 moves, it will drive the sliding block 79 and the extrusion rod 81 to move in the reverse direction through the sliding ring 711. The return spring 710 continues to reset. The card slot 781 still remains in the state of clamping both sides of the PCB board 3. The flipping slot 731 will squeeze the moving sliding block 79 to flip 180 degrees in the reverse direction. The sliding block 79 flipping 180 degrees in the reverse direction will drive the rhombic rod 75 to rotate 180 degrees in the reverse direction. Since the card slot 781 is still in the state of clamping the PCB board 3 at this time, the rhombic rod 75 will not drive the flipping rod 78 to rotate in the reverse direction under the action of the overrunning clutch II 77. At the same time, when the extrusion rod 81 moves in the reverse direction, the inclined surface of the extrusion block 83 will squeeze the strip-shaped protrusion of the extrusion rod 81 to make the extrusion rod 81 move horizontally. The tension spring II 82 is stretched. Subsequently, the extrusion rod 81 continues to move. The inclined surface of the extrusion block 83 no longer squeezes the strip-shaped protrusion of the extrusion rod 81. The tension spring II 82 resets to drive the extrusion rod 81 to reset. Then the sliding block 79 continues to move in the reverse direction. The return spring 710 completes the reset. The sliding block 79 drives the sliding column 74, the rhombic rod 75, the overrunning clutch II 77 and the flipping rod 78 to reset to the initial position together. The card slot 781 is disengaged from both sides of the PCB board 3. Then the staff can repeat the above operations again to enable the reverse test frame 62 to detect the reverse test points of the PCB board 3. After the reverse side of the PCB board 3 is detected, the PCB board 3 will be flipped back to the initial state again. At the same time, the positive test frame 61 and the reverse test frame 62 will also return to the initial state, thus facilitating the next detection;

[0049] In this way, after the positive test points of the PCB board 3 are detected by this device, the positive test frame 61 and the reverse test frame 62 will be switched immediately. At the same time, the PCB board 3 will be automatically flipped so that the reverse test points of the PCB board 3 correspond to the probes of the reverse test frame 62, thereby making the operation of the staff more convenient and improving the detection efficiency. After the test is over, the staff turns off the electric push rod 4 and takes out the detected PCB board 3.

[0050] Embodiment 2: On the basis of Embodiment 1, as Figures 13 - 17As shown, it further includes a positioning mechanism. The positioning mechanism is arranged on the support plate 23 and is used to position the PCB circuit board 3 before each detection. The positioning mechanism includes a rotating shaft 91, a gear 92, a positioning rod 93, a third tension spring 94, a rack 95 and a pressing frame 96. The two rotating shafts 91 are respectively rotatably connected to the bottoms of the two support plates 23. Gears 92 are connected to the two rotating shafts 91 by flat keys. The two gears 92 are respectively located below the two support plates 23. The two sides of the two support plates 23 are both slidably connected with positioning rods 93. The two positioning rods 93 on the same support plate 23 are a group. The two groups of positioning rods 93 are symmetrically arranged. The two positioning rods 93 in the same group are symmetrically arranged. The sides of the two groups of positioning rods 93 away from each other are respectively in contact with the two sides of the two flipping rods 78. The positioning rod 93 is used to position the PCB circuit board 3 and is used to squeeze the flipping rod 78 to move. Tension springs three 94 are respectively connected between the two groups of positioning rods 93 and the two support plates 23. There are four tension springs three 94 in total. The bottoms of the four positioning rods 93 are all welded with racks 95. The two racks 95 on the same support plate 23 are symmetrically arranged at the two sides of the gear 92 on the same support plate 23. The two racks 95 on the same support plate 23 are both meshed with the gear 92 on the same support plate 23. The bottom of the rotating plate 54 is rotatably connected with a pressing frame 96. The two sides of the pressing frame 96 are respectively slidably connected with the two sides of the limiting plate 2. The bottom of the pressing frame 96 is obliquely arranged.

[0051] During the detection, the rotating plate 54 moves downward to drive the extrusion frame 96 to move downward. After the extrusion frame 96 moves downward by a certain distance, it will contact one side of two of the positioning rods 93. Subsequently, the extrusion frame 96 continues to move downward to squeeze two of the positioning rods 93 to move towards the direction close to the PCB circuit board 3. The movement of two of the positioning rods 93 will drive two of the racks 95 to move. The movement of two of the racks 95 will drive the rotation of two gears 92 and the rotating shaft 91 to drive the other two racks 95 and the other two positioning rods 93 to move in the opposite direction. In this way, the four positioning rods 93 simultaneously move towards the direction close to the PCB circuit board 3 to position and clamp both sides of the PCB circuit board 3. The four tension springs three 94 are simultaneously stretched. When the four positioning rods 93 move, they will respectively squeeze both sides of the two flipping rods 78, so that the two flipping rods 78 move towards the direction close to the PCB circuit board 3 during the detection. The tension spring one 76 is stretched, so that the two card slots 781 catch the other two sides of the PCB circuit board 3 for positioning and clamping. In this way, during the detection of the PCB circuit board 3, the four sides of the PCB circuit board 3 can be positioned, thus saving the time for manual positioning by the staff, further improving the detection efficiency, and being able to clamp the four sides of the PCB circuit board 3, making the detection of the PCB circuit board 3 more stable, thereby enhancing the detection effect of the PCB circuit board 3. Subsequently, the rotating plate 54 resets upward to drive the extrusion frame 96 to reset. The extrusion frame 96 resets and no longer squeezes the positioning rods 93. The four tension springs two 82 reset to drive the four positioning rods 93 and the four racks 95 to reset together. The positioning rods 93 no longer squeeze the flipping rods 78, and the tension spring one 76 resets to drive the flipping rods 78 to reset.

[0052] Embodiment 3: On the basis of Embodiment 2, as Figures 7 - 19 shown, it further includes a cleaning mechanism. The cleaning mechanism is arranged on the limiting plate 2. The cleaning mechanism is used to blow off the dust on the required test surface of the PCB circuit board 3 before each test. The cleaning mechanism includes a blower group 101, a cross tube 102, an air outlet head 103, a tension spring four 104 and a pressure receiving frame 105. The two blower groups 101 are respectively installed on both lower sides of the limiting plate 2. The two blower groups 101 are both communicated with a cross tube 102. The two cross tubes 102 are both slidably connected with an air outlet head 103. The two air outlet heads 103 are symmetrically arranged. The two air outlet heads 103 are respectively communicated with the two cross tubes 102. Air outlet openings are respectively opened at one ends of the two air outlet heads 103 close to each other. The air outlet openings of the two air outlet heads 103 are both aligned with the top surface of the PCB circuit board 3. The air outlet head 103 is used to blow air on the surface of the PCB circuit board 3. Tension springs four 104 are respectively connected between the two air outlet heads 103 and the two cross tubes 102. Pressure receiving frames 105 are welded on the two air outlet heads 103. One sides of the two pressure receiving frames 105 away from each other respectively contact one sides of the two groups of return-shaped rods 72 close to each other. The return-shaped rods 72 are used to squeeze the pressure receiving frames 105 to move.

[0053] Before detecting the PCB board 3, the staff first start two blower groups 101. The blower groups 101 suck external air into the cross tube 102. Initially, the air outlet heads 103 block the cross tube 102. While the return rod 72 moves downward, it will squeeze the two pressure-receiving frames 105 to drive the two air outlet heads 103 to move towards each other. The tension spring four 104 is stretched. When the two air outlet heads 103 move and no longer block the cross tube 102, the air inhaled by the blower groups 101 will be input into the air outlet heads 103 through the cross tube 102. The movement of the air outlet heads 103 will evenly blow the internal air to the surface of the PCB board 3 through the air outlets of the air outlet heads 103, thereby cleaning the surface of the PCB board 3 before detection, making the detection of the PCB board 3 more accurate, and further enhancing the detection effect. When the positive test frame 61 and the negative test frame 62 detect the PCB board 3, the return rod 72 no longer squeezes the two pressure-receiving frames 105, and the tension spring four 104 resets to drive the pressure-receiving frames 105 and the air outlet heads 103 to reset. The air outlet heads 103 block the cross tube 102 again, and the air outlet heads 103 no longer clean the surface of the PCB board 3.

[0054] The above has introduced this application in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the method and its core idea of this application; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A PCB circuit board detection device, characterized in that, It includes an outer frame (1), a limit plate (2), a rotating rod (21), a torsion spring (22), a support plate (23), a PCB circuit board (3), an electric push rod (4), a detection mechanism, a flipping mechanism, an opening and closing mechanism, a positive test stand (61) and a negative test stand (62). An inlet (11) is formed on the outer frame (1). A limit plate (2) is fixedly connected inside the outer frame (1). Rotating rods (21) are rotatably connected to both sides of the bottom of the limit plate (2). The two rotating rods (21) are symmetrically arranged. Torsion springs (22) are connected between the two ends of the mutually remote sides of the two rotating rods (21) and the limit plate (2). There are a total of four torsion springs (22). Support plates (23) are fixedly connected to the mutually close sides of the two rotating rods (21). The two support plates (23) are symmetrically arranged. A PCB circuit board (3) is placed between the tops of the two support plates (23). A number of test points are provided on both the upper and lower sides of the PCB circuit board (3). Electric push rods (4) are installed on both sides of the top of the outer frame (1). A detection mechanism for detecting the front and back sides of the PCB circuit board (3) is provided on the electric push rod (4). A positive test stand (61) for detecting the front side of the PCB circuit board (3) and a negative test stand (62) for detecting the back side of the PCB circuit board (3) are provided on the detection mechanism. A flipping mechanism for flipping the PCB circuit board (3) is provided on the detection mechanism. An opening and closing mechanism for opening and closing the support plate (23) is provided on the flipping mechanism; The detection mechanism includes a support frame (51), a compression spring (52), a friction block (53), a rotating plate (54), an extrusion column (55), a limit block (56), an overrunning clutch one (57) and an extrusion ring (58). The support frame (51) is slidably connected between the bottoms of the telescopic rods of the two electric push rods (4). Compression springs (52) are connected between the two sides of the support frame (51) and the telescopic rods of the two electric push rods (4). Two friction blocks (53) are installed on the support frame (51). The two friction blocks (53) are symmetrically arranged. A rotating plate (54) is rotatably connected to the support frame (51). The rotating plate (54) is perpendicular to the support frame (51). The top side of the rotating plate (54) is a spline groove structure. Both friction blocks (53) are in contact with the spline groove structure of the rotating plate (54). A positive test stand (61) and a negative test stand (62) are respectively installed on both bottom sides of the rotating plate (54). Among them, the positive test stand (61) is located directly above the PCB circuit board (3). An extrusion column (55) is fixedly connected to the top of the rotating plate (54). Two extrusion grooves (551) are evenly spaced on the side of the extrusion column (55). A limit block (56) is fixedly connected to the limit plate (2). An overrunning clutch one (57) is installed inside the limit block (56). An extrusion ring (58) is installed inside the overrunning clutch one (57). The extrusion ring (58) is sleeved on the extrusion column (55). Two columnar protrusions are evenly spaced on the inside of the extrusion ring (58). The two columnar protrusions of the extrusion ring (58) are respectively located in the two extrusion grooves (551).

2. The PCB circuit board detection device according to claim 1, wherein, A number of probes are provided on both the positive test stand (61) and the negative test stand (62). The several probes on the positive test stand (61) respectively correspond to several test points on the front of the PCB circuit board (3), and the several probes on the negative test stand (62) respectively correspond to several test points on the back of the PCB circuit board (3).

3. A PCB circuit board detection device according to claim 1, characterized in that, The extrusion groove (551) is composed of a vertical groove and a threaded groove. The vertical groove and the threaded groove of the extrusion groove (551) are connected. The vertical groove of the extrusion groove (551) is located above the threaded groove of the extrusion groove (551). The two columnar protrusions of the extrusion ring (58) are respectively located at the bottoms of the threaded grooves of the two extrusion grooves (551).

4. A PCB circuit board detection device according to claim 1, characterized in that, The flipping mechanism includes a moving rod (71), a looped rod (72), a limiting sleeve (73), a sliding column (74), a rhombic rod (75), a first tension spring (76), an overrunning clutch two (77), a flipping rod (78), a sliding block (79), a return spring (710), a sliding ring (711) and a sliding rod (712). The moving rod (71) is fixedly connected to the support frame (51). Two looped rods (72) are fixedly connected to both sides of the moving rod (71). Four looped rods (72) are each provided with a looped groove (721). The two looped rods (72) on the same side form a group, and the two groups of looped rods (72) are symmetrically arranged. The two looped rods (72) in the same group are symmetrically arranged. Limiting sleeves (73) are fixedly connected to both sides of the limiting plate (2). The two limiting sleeves (73) are symmetrically arranged. Two flipping grooves (731) are opened on each of the two limiting sleeves (73). A sliding column (74) is slidably connected to the side of each of the two limiting sleeves (73) close to each other. A rhombic rod (75) is slidably connected to the side of each of the two sliding columns (74) close to each other. A first tension spring (76) is connected between each of the two rhombic rods (75) and the corresponding sliding column (74). A frosted surface is provided at each of the ends of the two rhombic rods (75) close to each other. An overrunning clutch two (77) is installed on each of the ends of the two rhombic rods (75) close to each other. A flipping rod (78) is installed on the outside of each of the two overrunning clutches two (77). Frosted surfaces are also provided at the ends of the two flipping rods (78) away from each other. The frosted surfaces of the two flipping rods (78) are in contact with the frosted surfaces of the two rhombic rods (75). Card slots (781) are opened on the sides of the two flipping rods (78) close to each other. The two card slots (781) correspond to both sides of the PCB circuit board (3) respectively. Sliding blocks (79) are slidably connected to the upper and lower sides of each of the two sliding columns (74). There are four sliding blocks (79) in total. The two sliding blocks (79) on the same sliding column (74) respectively pass through the two flipping grooves (731) on the same limiting sleeve (73). A return spring (710) is connected between each of the two sliding blocks (79) on the same sliding column (74) and the corresponding sliding column (74). There are four return springs (710) in total. Sliding rings (711) are sleeved on each of the two limiting sleeves (73). The parts of the two sliding blocks (79) on the same sliding column (74) exposed from the limiting sleeve (73) are located within the sliding rings (711) on the same limiting sleeve (73). Sliding rods (712) are fixedly connected to both sides of each of the two sliding rings (711). The four sliding rods (712) are all slidably connected to the limiting plate (2). The two sliding rods (712) on the same sliding ring (711) form a group, and the two groups of sliding rods (712) are symmetrically arranged. The two sliding rods (712) in the same group are symmetrically arranged. The ends of the two groups of sliding rods (712) away from each other are respectively located within the looped grooves (721) of the two groups of looped rods (72).

5. A PCB circuit board detection device according to claim 4, characterized in that, The opening and closing mechanism includes a pressing rod (81), a second tension spring (82) and a pressing block (83). The four pressing rods (81) are respectively connected to the four sliding rods (712) in a sliding manner. The four pressing rods (81) are all located below the limiting plate (2). The two pressing rods (81) on the same side are taken as a group, and the two groups of pressing rods (81) are symmetrically arranged. The two pressing rods (81) in the same group are symmetrically arranged. Second tension springs (82) are connected between the four pressing rods (81) and the four sliding rods (712) respectively. At both ends of the sides where the two rotating rods (21) are far away from each other, pressing blocks (83) are fixedly connected. The two pressing blocks (83) on the same rotating rod (21) are taken as a group, and the two groups of pressing blocks (83) are symmetrically arranged. The two pressing blocks (83) in the same group are symmetrically arranged.

6. The PCB circuit board detection device according to claim 5, characterized in that, Strip-shaped protrusions are provided at the bottoms of the four pressing rods (81).

7. The PCB circuit board detection device according to claim 5, wherein On the sides where the two groups of pressing blocks (83) are close to each other, inclined surfaces are provided, and on the sides where the two groups of pressing blocks (83) are far away from each other, straight surfaces are provided.

8. A PCB circuit board detection device according to claim 5, characterized in that, A positioning mechanism is further included. The positioning mechanism is arranged on the support plate (23) and is used to position the PCB board (3) before each detection. The positioning mechanism includes a rotating shaft (91), a gear (92), a positioning rod (93), a third tension spring (94), a rack (95) and a pressing frame (96). The two rotating shafts (91) are respectively rotatably connected to the bottoms of the two support plates (23). Gears (92) are fixedly connected to the two rotating shafts (91). The two gears (92) are respectively located below the two support plates (23). The two sides of the two support plates (23) are slidably connected with positioning rods (93). The two positioning rods (93) on the same support plate (23) are taken as a group, and the two groups of positioning rods (93) are symmetrically arranged. The two positioning rods (93) in the same group are symmetrically arranged. The sides where the two groups of positioning rods (93) are far away from each other are respectively in contact with the two sides of the two flipping rods (78). Third tension springs (94) are connected between the two groups of positioning rods (93) and the two support plates (23) respectively. There are four third tension springs (94) in total. Racks (95) are fixedly connected to the bottoms of the four positioning rods (93). The two racks (95) on the same support plate (23) are symmetrically arranged at both sides of the gear (92) that is centrosymmetrically arranged on the same support plate (23). The two racks (95) on the same support plate (23) are both meshed with the gear (92) on the same support plate (23). A pressing frame (96) is rotatably connected to the bottom of the rotating plate (54). The two sides of the pressing frame (96) are respectively slidably connected to the two sides of the limiting plate (2). The bottom of the pressing frame (96) is obliquely arranged.

9. A PCB circuit board detection device according to claim 8, characterized in that, It further includes a cleaning mechanism which is arranged on the limit plate (2). The cleaning mechanism is used to blow off the dust on the required test surface of the PCB board (3) before each test. The cleaning mechanism includes a fan group (101), a cross tube (102), an air outlet head (103), a fourth tension spring (104) and a pressure-receiving frame (105). The two fan groups (101) are respectively installed on the lower sides of both sides of the limit plate (2). The cross tubes (102) are communicated with the two fan groups (101). The air outlet heads (103) are slidably connected to the two cross tubes (102). The two air outlet heads (103) are symmetrically arranged. The two air outlet heads (103) are respectively communicated with the two cross tubes (102). Air outlet openings are formed at the ends of the two air outlet heads (103) close to each other. The air outlet openings of the two air outlet heads (103) are both aligned with the top surface of the PCB board (3). The fourth tension springs (104) are connected between the two air outlet heads (103) and the two cross tubes (102) respectively. The pressure-receiving frames (105) are fixedly connected to the two air outlet heads (103). The sides of the two pressure-receiving frames (105) away from each other are respectively in contact with the sides of the two groups of return-shaped rods (72) close to each other.

Images