Mixture detecting and sampling method for road and bridge construction
By adopting an automated mixing inspection and sampling method in road and bridge construction, the sealing opening and closing mechanism, limit release mechanism and pre-ejection mechanism are used to solve the problem of inconvenient sampling of materials in the middle and bottom of the mixing container, and efficient and accurate material quality inspection is achieved.
Patent Information
- Application Number
- CN202411887903.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-03-21
AI Technical Summary
During the construction of road and bridges, it is difficult for the prior art to effectively sample materials in the middle and bottom of the mixing container, making it difficult to determine whether the overall material quality meets the standards.
A mixed detection and sampling method for road and bridge construction is adopted. By setting up a sealing opening and closing mechanism, limit release mechanism and pre-ejection mechanism between columns, installation frame ports, sampling boxes, electric telescopic rods, and insertion rods, multi-point sampling is achieved, and the sample loading, sealing and resolution of the sampling box are automatically completed.
This method can easily perform multi-point sampling to ensure that the materials in the middle and bottom of the mixing container can be effectively sampled and tested, solve the problem of inconvenience in the prior art, and improve the accuracy and efficiency of material quality detection.
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Figure CN119666464A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of road and bridge construction, in particular to a mixed material detection and sampling method for road and bridge construction. Background Art
[0002] During the construction of roads and bridges, materials need to be mixed. When mixing materials, a mixer is used to mix multiple materials together. If you want to inspect the mixed materials, you can only observe them with naked eyes through the reserved observation port of the mixer. You can only observe the materials on the surface, and you cannot observe the quality of the materials in the middle and bottom of the container. It is difficult to determine whether the overall material quality meets the standards. Therefore, it is necessary to sample the materials in the middle and bottom of the mixing container. Since multi-point sampling is inconvenient in the prior art, a mixed material detection sampling method for road and bridge construction is proposed to solve the problem of the inconvenience of existing multi-point sampling. Summary of the invention
[0003] In view of the deficiencies in the prior art, the present invention provides a mixed material detection sampling method for road and bridge construction, which solves the problem of inconvenience in multi-point sampling of mixed materials.
[0004] To achieve the above purpose, the present invention is implemented by the following technical scheme: a mixed material detection sampling method for road and bridge construction, specifically comprising the following steps: Step 1: pre-assembly of the container: placing a plurality of sampling boxes in sequence inside the installation frame opening. During the placement process, the socket presses the inclined block upward and the inclined block is reset downward, so that the socket and the inclined block form a locking limit, so that the sampling boxes are installed inside the installation frame opening; Step 2: Lowering for sampling: insert the column into the mixed material in the mixing container, and then start the electric telescopic rod. Through the cooperation of the electric telescopic rod, the first plug rod, the second plug rod and the sealing and opening and closing mechanism, the inlet limit of the sampling box installed inside the installation frame is automatically released, and the inlet is automatically opened for sample loading; Step 3: Container assembly release: The sealing and opening and closing mechanism is reset to synchronize the limit release mechanism, so that the sampling box inlet is automatically closed, and the installation limit of the sampling box is released simultaneously through the limit release mechanism; Step 4: Pre-ejection of container: The limit release mechanism releases the installation limit of the sampling box that receives the sample and is in a closed state. At the same time, the limit release mechanism synchronously links the pre-ejection mechanism to squeeze the sampling box that has been released from the limit, so that the sampling box is partially moved to the front side of the installation frame in advance.
[0005] Preferably, there are several mounting frame openings, and the plurality of mounting frame openings are opened on the front side of the column in a vertically equidistant array, a sampling box is arranged inside the mounting frame opening, an electric telescopic rod is fixedly connected to the top of the column, a first plug rod is fixedly connected to one side of the extended end of the electric telescopic rod, and the first plug rod slides and extends to the inside of the column, a second plug rod is fixedly connected to one side of the first plug rod, a sealing and opening and closing mechanism is arranged between the first plug rod, the second plug rod and the sampling box, a limit release mechanism is arranged between the sealing and opening and closing mechanism and the sampling box, and a pre-ejection mechanism is arranged between the limit release mechanism, the mounting frame opening and the sampling box.
[0006] Preferably, the sealing and opening and closing mechanism includes a sealing frame with a hole, which is fixedly arranged on the front side of the sampling box, and a U-shaped sealing plate is elastically slidably arranged on the bottom of the sampling box entrance through a groove, and latch rods are elastically slidably arranged on both sides of the sampling box, and latch holes matching the latch rods are provided on both sides of the front side of the U-shaped sealing plate, a beveled bracket matching the sampling box is fixedly arranged on the front side of the first plug rod, and a slot matching the beveled bracket is provided on the top of the latch rod, one side of the U-shaped sealing plate is fixedly connected to the U-shaped frame, and one side of the second plug rod is fixedly connected to a pressure rod matching the U-shaped frame.
[0007] Preferably, the limit release mechanism includes a storage slide groove, which is opened at the top of the inner cavity of the mounting frame, the internal sliding connection of the storage slide groove is provided with an inclined block, a third return spring is fixedly connected between the inclined block and the storage slide groove, the top of the sampling box is fixedly connected with a socket used in conjunction with the inclined block, and slide rail grooves are opened on both sides of the inner cavity of the bevel rack, and the internal sliding connection of the slide rail groove is provided with a transverse rod, and the opposite ends of the two transverse rods are respectively fixedly connected to the two sides of the inclined block.
[0008] Preferably, the pre-ejection mechanism includes a directional slide groove, which is opened at the top of the inner cavity of the mounting frame, and a directional slider is slidably connected inside the directional slide groove, a fourth return spring is fixedly connected between the directional slider and the directional slide groove, an L-shaped push plate is fixedly connected to the bottom of the directional slider, a trapezoidal plate is fixedly connected to the bottom of the transverse bend of the L-shaped push plate, and an extrusion frame used in conjunction with the trapezoidal plate is fixedly provided on the rear side of the inclined block.
[0009] Preferably, the front side of the perforated sealing frame is fixedly connected to a limiting sleeve via a bracket, a telescopic rod is slidably connected inside the limiting sleeve, and the top of the telescopic rod is fixedly connected to the bottom of the U-shaped sealing plate, and a first return spring is fixedly connected between the telescopic rod and the limiting sleeve.
[0010] Preferably, the front side of the column and the top and bottom portions located on both sides of the installation frame opening are fixedly connected with positioning hanging rods matched with the sealing frame with holes.
[0011] Preferably, a sliding column is fixedly connected to the top of the column, a limiting sliding sleeve is slidably connected to the surface of the sliding column, and one side of the limiting sliding sleeve is fixedly connected to the side surface of the second insertion rod.
[0012] Preferably, both sides of the upright column are fixedly connected with cross bars, the bottom of the cross bar is fixedly connected with a placement rack, and the top of the cross bar is fixedly connected with a handle.
[0013] Preferably, guide grooves are provided on both sides of the sampling box, and guide sliders are slidably connected inside the guide grooves. A second return spring is fixedly connected between adjacent guide sliders and guide grooves, and the opposite sides of the two guide sliders are fixedly connected to the opposite sides of the two latch rods respectively. Beneficial Effects
[0014] The present invention provides a mixed material detection sampling method for road and bridge construction. Compared with the existing technology, it has the following beneficial effects: (1) The method for sampling mixed material for road and bridge construction is characterized in that a sealing and opening and closing mechanism, a limit release mechanism and a pre-ejection mechanism are arranged between a column, an installation frame, a sampling box, an electric telescopic rod, a first plug rod and a second plug rod, so that the device can combine a column with a plurality of sampling boxes to perform multi-point sampling. At the same time, the sealing and opening and closing mechanism, the limit release mechanism and the pre-ejection mechanism can cooperate with each other to promote the automatic opening and closing of the sampling box inlet so as to carry and seal the sample, and simultaneously, the sampling box that seals the sample is automatically released from the fixing mode between the sampling box and the installation frame, so that the sampling box is easy to be taken out later, and simultaneously, the released sampling box is partially pushed out so as to be manually pulled out later.
[0015] (2) The mixed material detection sampling method for road and bridge construction is to fix a positioning hanging rod used in conjunction with a sealing frame with holes on the front side of a column, so that a sampling box can be conveniently hung and installed inside the installation frame opening through the fit between the sealing frame with holes and the positioning hanging rod.
[0016] (3) The mixed material detection sampling method for road and bridge construction is characterized in that a limit sleeve, a telescopic rod and a first reset spring are arranged between the U-shaped sealing plate and the sealing frame with holes, so that after the U-shaped sealing plate loses its pressing force, it can be elastically reset in time through the reset cooperation of the limit sleeve, the telescopic rod and the first reset spring, thereby sealing the inlet of the sampling box.
[0017] (4) In the mixed material detection sampling method for road and bridge construction, a pressure rod and a U-shaped frame are arranged between the second insertion rod and the U-shaped sealing plate, so that the U-shaped sealing plate can be staggered forward and backward through the U-shaped frame and the pressure rod without affecting the normal travel coordination, thereby achieving the effect of facilitating the unobstructed disassembly and assembly of the sampling box. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the process of the present invention; Figure 2 It is a schematic diagram of the external structure of the present invention; Figure 3 It is a side view of the internal structure of the column of the present invention; Figure 4 is a cross-sectional view of the column structure of the present invention; Figure 5 For the present invention Figure 2 A partial enlarged view of the middle A; Figure 6 For the present invention Figure 3 A partial enlarged view of point B in the middle; Figure 7 For the present invention Figure 4 A partial enlarged view of point C in the middle; Figure 8 It is a schematic diagram of the sealing and opening and closing mechanism structure of the present invention; Fig. 9 It is a schematic diagram of the sealing and opening and closing mechanism structure of the present invention; Fig.10 It is a schematic diagram of the sealing and opening and closing mechanism structure of the present invention; Fig.11 It is a schematic diagram of the limit release mechanism structure of the present invention; Fig.12 It is a schematic diagram of the pre-ejection mechanism structure of the present invention.
[0019] In the figure: 1, column; 2, installation frame opening; 3, sampling box; 4, electric telescopic rod; 5, first plug rod; 6, second plug rod; 7, sealing and opening and closing mechanism; 702, sealing frame with holes; 703, U-shaped sealing plate; 704, latch rod; 705, latch hole; 706, beveled edge rack; 707, slot; 708, U-shaped rack; 709, pressure rod; 8, limit release mechanism; 801, storage slide; 802, oblique block; 803, third return spring; 804, socket; 805, slide rail Groove; 806, transverse rod; 9, pre-ejection mechanism; 901, directional slide groove; 902, directional slider; 903, fourth return spring; 904, L-shaped push plate; 905, trapezoidal plate; 906, extrusion frame; 10, limit sleeve; 11, telescopic rod; 12, first return spring; 13, positioning suspension rod; 14, sliding column; 15, limit sleeve; 16, cross bar; 17, placement rack; 18, handle; 19, guide slide groove; 20, guide slider; 21, second return spring. DETAILED DESCRIPTION
[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0021] See also Figure 1-12 The present invention provides a technical solution: a mixed material detection sampling method for road and bridge construction, which specifically comprises the following steps: Step 1: Container pre-assembly: multiple sampling boxes 3 are sequentially placed inside the installation frame 2. During the placement process, the socket 804 presses the inclined block 802 upward, and the inclined block 802 is reset downward, so that the socket 804 and the inclined block 802 form a locking limit, so that the sampling boxes 3 are installed inside the installation frame 2; Step 2: Lowering for sampling: insert the column 1 into the mixed material in the mixing container, and then start the electric telescopic rod 4. Through the cooperation of the electric telescopic rod 4, the first plug rod 5, the second plug rod 6 and the sealing and opening and closing mechanism 7, the sampling box 3 installed in the installation frame 2 is automatically released from its inlet limit, and the inlet is automatically opened for sample loading; When the locking cam 706 is in the unlocking state, the locking cam 706 is in the unlocking state, and the locking cam 706 is in the unlocking state. Step 3, container assembly release: the sealing and opening and closing mechanism 7 resets the synchronous linkage limit release mechanism 8, so that the inlet of the sampling box 3 is automatically closed, and the installation limit of the sampling box 3 is released synchronously by the limit release mechanism 8; After the sampling box 3 is loaded with the sample, the height of the extended end of the electric telescopic rod 4 is reset, so that the U-shaped sealing plate 703 is prompted to close the inlet of the sampling box 3, and the U-shaped sealing plate 703 and the sampling box 3 are simultaneously prompted to continue to maintain a stable closed limit state. After the height of the extended end of the electric telescopic rod 4 is reset, the column 1 is pulled out of the material pile as a whole, and then the extended end of the electric telescopic rod 4 is continued to be controlled to rise. The extended end of the electric telescopic rod 4 continues to rise, and the bevel bracket 706 is synchronously driven to rise through the first plug rod 5. The bevel bracket 706 rises to support the horizontal rod 806 to rise. The horizontal rod 806 rises and drives the inclined block 802 to rise. The inclined block 802 rises and disengages from the engagement limit with the socket 804, so that the sampling box 3 is released from fixation; Step 4: Pre-ejection of container: The limit release mechanism 8 releases the installation limit of the sampling box 3 that receives the sample and is in a closed state. At the same time, the limit release mechanism 8 synchronously links the pre-ejection mechanism 9 to squeeze the released sampling box 3, so that the sampling box 3 is partially moved to the front side of the installation frame 2 in advance; After the inclined block 802 and the socket 804 are disengaged from the limit engagement, the bevel bracket 706 continues to support the horizontal rod 806, prompting the inclined block 802 to continue to rise. The continued rise of the inclined block 802 will drive the extrusion frame 906 to approach the bottom of the trapezoidal plate 905 and squeeze the trapezoidal plate 905. The trapezoidal plate 905 is forced to drive the L-shaped push plate 904 forward, and the L-shaped push plate 904 moves forward to drag the sampling box 3 to slide partially toward the front side of the installation frame opening 2.
[0022] There are several mounting frame openings 2, and several mounting frame openings 2 are opened in a vertically equidistant array on the front side of the column 1. A sampling box 3 is arranged inside the mounting frame opening 2. An electric telescopic rod 4 is fixedly connected to the top of the column 1, and a first plug rod 5 is fixedly connected to one side of the extended end of the electric telescopic rod 4, and the first plug rod 5 slides and extends to the inside of the column 1, and a second plug rod 6 is fixedly connected to one side of the first plug rod 5. A sliding column 14 is fixedly connected to the top of the column 1, and a limiting sleeve 15 is slidably connected to the surface of the sliding column 14, and one side of the limiting sleeve 15 is fixedly connected to the side of the second plug rod 6. Both sides of the column 1 are fixedly connected to a cross bar 16, a placement rack 17 is fixedly connected to the bottom of the cross bar 16, and a handle 18 is fixedly connected to the top of the cross bar 16.
[0023] A sealing and opening and closing mechanism 7 is provided between the first plug rod 5, the second plug rod 6 and the sampling box 3, and the sealing and opening and closing mechanism 7 includes a perforated sealing frame 702, the perforated sealing frame 702 is fixedly arranged on the front side of the sampling box 3, a U-shaped sealing plate 703 is elastically slidably provided on the bottom of the inlet of the sampling box 3 through a slot, and latch rods 704 are elastically slidably provided on both sides of the sampling box 3, and latch holes 705 used in conjunction with the latch rods 704 are provided on both sides of the front side of the U-shaped sealing plate 703, a beveled edge bracket 706 used in conjunction with the sampling box 3 is fixedly provided on the front side of the first plug rod 5, and a slot 707 used in conjunction with the beveled edge bracket 706 is provided on the top of the latch rod 704, a U-shaped frame 708 is fixedly connected to one side of the U-shaped sealing plate 703, and a pressure rod 709 used in conjunction with the U-shaped frame 708 is fixedly connected to one side of the second plug rod 6; As a detailed description: the front side of the perforated sealing frame 702 is fixedly connected to the limiting sleeve 10 through a bracket, the internal sliding connection of the limiting sleeve 10 is connected to a telescopic rod 11, and the top of the telescopic rod 11 is fixedly connected to the bottom of the U-shaped sealing plate 703, and the first return spring 12 is fixedly connected between the telescopic rod 11 and the limiting sleeve 10. The front side of the column 1 and the top and bottom of both sides of the installation frame opening 2 are fixedly connected with a positioning suspension rod 13 used in conjunction with the perforated sealing frame 702, and both sides of the sampling box 3 are provided with a guide slot 19, and the internal sliding connection of the guide slide 20 is connected, and the second return spring 21 is fixedly connected between the adjacent guide slides 20 and the guide slot 19, and the opposite sides of the two guide slides 20 are fixedly connected to the opposite sides of the two latch rods 704.
[0024] A limit release mechanism 8 is arranged between the sealing and opening and closing mechanism 7 and the sampling box 3, and the limit release mechanism 8 includes a storage slide groove 801, and the storage slide groove 801 is opened at the top of the inner cavity of the installation frame 2, and the storage slide groove 801 is internally slidably connected with an inclined block 802, and a third reset spring 803 is fixedly connected between the inclined block 802 and the storage slide groove 801, and the top of the sampling box 3 is fixedly connected with a socket 804 used in conjunction with the inclined block 802, and both sides of the inner cavity of the bevel bracket 706 are opened with slide rail grooves 805, and the slide rail grooves 805 are internally slidably connected with transverse rods 806, and the opposite ends of the two transverse rods 806 are respectively fixedly connected to the two sides of the inclined block 802.
[0025] A pre-ejection mechanism 9 is arranged between the limit release mechanism 8, the installation frame mouth 2 and the sampling box 3, and the pre-ejection mechanism 9 includes a directional slide groove 901, the directional slide groove 901 is opened at the top of the inner cavity of the installation frame mouth 2, and a directional slider 902 is slidably connected inside the directional slide groove 901, and a fourth reset spring 903 is fixedly connected between the directional slider 902 and the directional slide groove 901, and an L-shaped push plate 904 is fixedly connected to the bottom of the directional slider 902, and a trapezoidal plate 905 is fixedly connected to the bottom of the transverse bending part of the L-shaped push plate 904, and an extrusion frame 906 used in conjunction with the trapezoidal plate 905 is fixedly arranged on the rear side of the inclined block 802.
Claims
1. A mixed material detection sampling method for road and bridge construction, characterized in that: The specific steps include: Step 1: pre-assembly of the container: placing a plurality of sampling boxes (3) in sequence inside the installation frame opening (2); during the placement process, the socket (804) presses the inclined block (802) upward, and the inclined block (802) is reset by descending, so that the socket (804) and the inclined block (802) form a locking limit, so that the sampling boxes (3) are installed inside the installation frame opening (2); Step 2, lowering for sampling: inserting the column (1) into the mixed material in the mixing container, and then starting the electric telescopic rod (4), through the cooperation of the electric telescopic rod (4), the first insertion rod (5), the second insertion rod (6) and the sealing and opening and closing mechanism (7), the inlet limit of the sampling box (3) installed in the installation frame (2) is automatically released, and the inlet is automatically opened for sample loading; Step 3: container assembly release: the sealing and opening and closing mechanism (7) resets the synchronous linkage limit release mechanism (8), so that the inlet of the sampling box (3) is automatically closed, and the installation limit of the sampling box (3) is released synchronously through the limit release mechanism (8); Step 4: Pre-ejection of the container: The limit release mechanism (8) releases the installation limit of the sampling box (3) that receives the sample and is in a closed state. At the same time, the limit release mechanism (8) is synchronously linked with the pre-ejection mechanism (9) to squeeze the sampling box (3) that has been released from the limit, so that the sampling box (3) is partially moved to the front side of the installation frame (2) in advance.
2. A mixed material detection sampling method for road and bridge construction according to claim 1, characterized in that: A plurality of the installation frame openings (2) are provided, and the plurality of installation frame openings (2) are arranged in an array at equal intervals in a vertical direction on the front side of the column (1); a sampling box (3) is provided inside the installation frame opening (2); an electric telescopic rod (4) is fixedly connected to the top of the column (1); a first plug rod (5) is fixedly connected to one side of the extended end of the electric telescopic rod (4); the first plug rod (5) is slidably extended to the inside of the column (1); a second plug rod (6) is fixedly connected to one side of the first plug rod (5); a sealing opening and closing mechanism (7) is provided between the first plug rod (5), the second plug rod (6) and the sampling box (3); a limit release mechanism (8) is provided between the sealing opening and closing mechanism (7) and the sampling box (3); and a pre-ejection mechanism (9) is provided between the limit release mechanism (8), the installation frame opening (2) and the sampling box (3).
3. A mixed material detection sampling method for road and bridge construction according to claim 1, characterized in that: The sealing and opening and closing mechanism (7) comprises a sealing frame (702) with a hole, the sealing frame (702) with a hole is fixedly arranged on the front side of the sampling box (3), a U-shaped sealing plate (703) is elastically slidably arranged on the bottom of the inlet of the sampling box (3) through a slot, latch rods (704) are elastically slidably arranged on both sides of the sampling box (3), latch holes (705) for use with the latch rods (704) are provided on both sides of the front side of the U-shaped sealing plate (703), a beveled edge bracket (706) for use with the sampling box (3) is fixedly arranged on the front side of the first plug rod (5), a slot (707) for use with the beveled edge bracket (706) is provided on the top of the plug rod (704), a U-shaped bracket (708) is fixedly connected to one side of the U-shaped sealing plate (703), and a pressure rod (709) for use with the U-shaped bracket (708) is fixedly connected to one side of the second plug rod (6).
4. A mixed material detection sampling method for road and bridge construction according to claim 1, characterized in that: The limit release mechanism (8) comprises a receiving slide groove (801), the receiving slide groove (801) is provided at the top of the inner cavity of the mounting frame opening (2), the interior of the receiving slide groove (801) is slidably connected to an inclined block (802), a third return spring (803) is fixedly connected between the inclined block (802) and the receiving slide groove (801), the top of the sampling box (3) is fixedly connected to a socket (804) matched with the inclined block (802), both sides of the inner cavity of the bevel bracket (706) are provided with slide rail grooves (805), the interior of the slide rail groove (805) is slidably connected to a transverse rod (806), and opposite ends of the two transverse rods (806) are respectively fixedly connected to the two sides of the inclined block (802).
5. The mixed material detection sampling method for road and bridge construction according to claim 1 is characterized in that: The pre-ejection mechanism (9) comprises a directional slide groove (901), the directional slide groove (901) is arranged at the top of the inner cavity of the mounting frame opening (2), a directional slider (902) is slidably connected inside the directional slide groove (901), a fourth return spring (903) is fixedly connected between the directional slider (902) and the directional slide groove (901), an L-shaped push plate (904) is fixedly connected to the bottom of the directional slider (902), a trapezoidal plate (905) is fixedly connected to the bottom of the transverse bending part of the L-shaped push plate (904), and an extrusion frame (906) matched with the trapezoidal plate (905) is fixedly arranged on the rear side of the inclined block (802).
6. A mixed material detection sampling method for road and bridge construction according to claim 3, characterized in that: The front side of the perforated sealing frame (702) is fixedly connected to a limiting sleeve (10) via a bracket, a telescopic rod (11) is slidably connected inside the limiting sleeve (10), and the top of the telescopic rod (11) is fixedly connected to the bottom of the U-shaped sealing plate (703), and a first return spring (12) is fixedly connected between the telescopic rod (11) and the limiting sleeve (10).
7. A mixed material detection sampling method for road and bridge construction according to claim 3, characterized in that: Positioning suspension rods (13) matched with the perforated sealing frame (702) are fixedly connected to the front side of the column (1) and the top and bottom located on both sides of the installation frame opening (2).
8. A mixed material detection sampling method for road and bridge construction according to claim 1, characterized in that: The top of the column (1) is fixedly connected to a sliding column (14), the surface of the sliding column (14) is slidably connected to a limiting sliding sleeve (15), and one side of the limiting sliding sleeve (15) is fixedly connected to the side surface of the second insertion rod (6).
9. A mixed material detection sampling method for road and bridge construction according to claim 1, characterized in that: Both sides of the upright post (1) are fixedly connected to a cross bar (16), the bottom of the cross bar (16) is fixedly connected to a placement frame (17), and the top of the cross bar (16) is fixedly connected to a handle (18).
10. A mixed material detection sampling method for road and bridge construction according to claim 3, characterized in that: Guide grooves (19) are provided on both sides of the sampling box (3), and guide sliders (20) are slidably connected inside the guide grooves (19). A second return spring (21) is fixedly connected between adjacent guide sliders (20) and guide grooves (19), and opposite sides of the two guide sliders (20) are fixedly connected to opposite sides of two latch rods (704) respectively.