Marshall test specimen stripping machine

Abstract

This utility model relates to the field of demolding machine technology and discloses a Marshall specimen demolding machine, including a machine body, a hydraulic ejector rod on the machine body, a sliding plate slidably mounted on the machine body, two workstations on the sliding plate, a centering mechanism and a limiting mechanism on each workstation, and an exposure groove on each workstation that is adapted to the hydraulic ejector rod. This utility model, through its sliding dual-workstation design, precise centering and limiting mechanisms, and stable hydraulic ejection system, achieves efficient, accurate, and safe demolding operations, while adapting to the needs of molds of different sizes.

Description

Technical Field

[0001] This utility model relates to the field of demolding machine technology, specifically a Marshall specimen demolding machine. Background Technology

[0002] Marshall specimens are commonly used test samples in the mechanical property testing of asphalt mixtures. They are widely used in road engineering to evaluate the stability and durability of asphalt concrete. After the specimens are compacted and molded, they need to be removed from the mold. This process is usually called demolding. Traditional demolding methods often use manual knocking or simple mechanical devices, which are not only labor-intensive and inefficient, but also easily cause damage to the specimens or affect the accuracy of subsequent test results.

[0003] The patent with publication number CN222419748U discloses a Marshall specimen demolding machine, including a base assembly, an adjustment assembly, and a demolding assembly. The base assembly includes a base platform, the adjustment assembly includes a lead screw, and the demolding assembly includes a demolding clamping plate. The output end of the cylinder is connected to a mounting block, and the end of the mounting block away from the cylinder is connected to a demolding top plate. A limit rod is provided on the inner side of the support side block, and one end of the compression spring is connected to a clamping side plate. The end of the clamping side plate away from the compression spring is connected to an anti-slip pad layer.

[0004] However, the above-mentioned device has the following problems when in use: the device has poor adaptability to Marshall molds of different diameters and is difficult to flexibly meet diverse usage needs. At the same time, the molds need to be disassembled and installed repeatedly at the same workstation during operation. The connection between the demolding actions of adjacent molds is not smooth and the continuity is poor, which affects the overall work rhythm. Utility Model Content

[0005] The purpose of this invention is to solve the problems existing in the prior art by proposing a Marshall specimen demolding machine that enhances the equipment's versatility, operational reliability, and usage efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A Marshall specimen demolding machine includes a machine body, on which a hydraulic ejector rod is provided. A sliding plate is slidably mounted on the machine body. The sliding plate has two stations. Each station of the sliding plate is provided with a centering mechanism and a limiting mechanism. Each station of the sliding plate has an exposure groove, which is adapted to the hydraulic ejector rod.

[0008] Preferably, the centering mechanism includes a first fixed frame and a second fixed frame, both of which are fixedly mounted on a sliding plate. A bidirectional lead screw is rotatably mounted on the first fixed frame, and two lead screw nuts are threaded onto the bidirectional lead screw. A connecting block is fixedly mounted on each of the two lead screw nuts, and an upper centering block and a lower centering block are fixedly mounted on the two connecting blocks respectively. The other ends of the upper and lower centering blocks are slidably mounted on the second fixed frame, and one end of the bidirectional lead screw passes through the first fixed frame and is fixedly mounted with a handwheel.

[0009] Preferably, both the upper and lower centering blocks are V-shaped, and the upper and lower centering blocks are installed in a staggered manner.

[0010] Preferably, the limiting mechanism includes a threaded rod, which is rotatably mounted on an upper centering block. A threaded sleeve is threadedly mounted on the threaded rod, and a lifting block is fixedly mounted on the threaded sleeve. A pressing strip is provided on the lifting block, and an operating block is fixedly mounted on the side of the threaded rod opposite to the upper centering block.

[0011] Preferably, the lifting block coincides with the upper centering block in the vertical direction, and the pressing strip is embedded on both sides of the lifting block facing inward. The pressing strip can directly contact the upper surface of the mold.

[0012] Preferably, two guide rods are fixedly installed on the upper centering block, and the lifting block is slidably installed on the two guide rods.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] (1) This utility model uses a sliding plate to design two workstations (left workstation and right workstation), and with the precise sliding positioning of the sliding plate on the machine body, it realizes an efficient continuous operation mode. The operator can perform mold placement, specimen preparation and other operations at one workstation while the other workstation performs hydraulic ejection demolding. When the demolding is completed at one workstation, the operator only needs to slide and switch the sliding plate 3 to immediately demold the specimen prepared at the other workstation, which greatly reduces the equipment waiting time and increases the demolding efficiency by more than double. The assembly line operation of the two workstations significantly improves the overall work efficiency, and is especially suitable for laboratory environments that need to process a large number of specimens.

[0015] (2) The centering mechanism in this utility model uses a bidirectional screw to drive two misaligned V-shaped centering blocks to move synchronously towards or away from each other. The V-shaped block design utilizes the principle of automatic centering, which can steplessly adjust and quickly and accurately position standard Marshall molds of different diameters at the geometric center of the workstation (i.e., directly above the axis of the hydraulic ejector rod), ensuring that the ejection force is strictly applied vertically along the mold axis, avoiding damage to the specimen or equipment caused by off-center loading. The limiting mechanism drives the threaded rod through the operating block, which drives the lifting block with the pressure strip to descend precisely and vertically along the guide rod. The pressure strip presses against the upper end face (flange edge) of the mold, effectively preventing the mold from being lifted during demolding. This not only ensures the high precision and specimen integrity of each demolding action, but also greatly enhances the equipment's versatility and operational reliability by adapting to different mold sizes (within the adjustment range). The overall structure is compact, the operation is intuitive, and the maintenance is convenient. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a Marshall specimen demolding machine proposed in this utility model;

[0017] Figure 2 This is a schematic diagram showing the installation position of the hydraulic ejector rod of a Marshall specimen demolding machine proposed in this utility model;

[0018] Figure 3 This is a schematic diagram showing the installation position of the centering mechanism of a Marshall specimen demolding machine proposed in this utility model;

[0019] Figure 4 This is a schematic diagram of the centering mechanism of a Marshall specimen demolding machine proposed in this utility model;

[0020] Figure 5 This is a schematic diagram of the limiting mechanism of a Marshall specimen demolding machine proposed in this utility model.

[0021] In the diagram: 1. Machine body; 2. Hydraulic ejector rod; 3. Sliding plate; 4. Exposed groove; 5. First fixed frame; 6. Second fixed frame; 7. Upper centering block; 8. Lower centering block; 9. Connecting block; 10. Double-acting lead screw; 11. Lead screw nut; 12. Handwheel; 13. Lifting block; 14. Pressure strip; 15. Threaded rod; 16. Threaded sleeve; 17. Operating block; 18. Guide rod. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0023] Please see Figures 1 to 5A Marshall specimen demolding machine includes a body 1, on which a hydraulic ejector rod 2 is mounted. The body 1 serves as the basic structure and support frame of the entire demolding machine, while the hydraulic ejector rod 2 is the core demolding power component, typically driven by a hydraulic pump station. During demolding, the hydraulic ejector rod 2 extends upward, and its top plate directly acts on the bottom of the Marshall specimen mold, applying an ejection force to smoothly and vertically eject the compacted asphalt mixture specimen from the mold cylinder. Since the hydraulic ejector rod 2 is existing technology and has been sufficiently disclosed, it will not be described in detail here.

[0024] A sliding plate 3 is slidably installed on the machine body 1. The sliding plate 3 has two working positions. Both working positions of the sliding plate 3 are equipped with a centering mechanism and a limiting mechanism. Both working positions of the sliding plate 3 have an exposed groove 4, which is adapted to the hydraulic ejector rod 2.

[0025] The sliding plate 3 can slide left and right along the guide rail on the machine body 1. The design of two stations (left station and right station) allows the operator to perform demolding operation at the other station while preparing the test piece at one station (placing the mold, installing the demolding sleeve, etc.), which greatly improves work efficiency. The function of the exposed groove 4 below each station is that when the station slides to the demolding position (i.e. directly above the hydraulic ejector rod 2), the hydraulic ejector rod 2 can pass through the exposed groove 4 without obstruction and directly act on the bottom of the mold to perform the ejection operation. The centering mechanism and the limiting mechanism are used to ensure that the mold is accurately positioned and stably pressed on the station, respectively.

[0026] The sliding stroke of the sliding plate 3 is limited, and the endpoint of its left and right sliding is determined by the groove on the machine body 1. When the sliding plate 3 is pushed to the leftmost side and abuts against the left side of the machine body 1, the exposed groove 4 of its right station is precisely aligned with the center line of the hydraulic ejector rod 2. At this time, the mold placed in the right station can be demolded. Similarly, when the sliding plate 3 is pushed to the rightmost side and abuts against the right side of the machine body 1, the exposed groove 4 of the left station is aligned with the hydraulic ejector rod 2, and the mold in the left station can be demolded. This design ensures the precise alignment and reliability of the demolding action.

[0027] like Figure 4 , Figure 5 As shown, the centering mechanism includes a first fixed frame 5 and a second fixed frame 6. Both the first fixed frame 5 and the second fixed frame 6 are fixedly mounted on the sliding plate 3. A bidirectional lead screw 10 is rotatably mounted on the first fixed frame 5. Two lead screw nuts 11 are threaded onto the bidirectional lead screw 10. Connecting blocks 9 are fixedly mounted on both lead screw nuts 11. An upper centering block 7 and a lower centering block 8 are fixedly mounted on the two connecting blocks 9, respectively. The other ends of the upper centering block 7 and the lower centering block 8 are slidably mounted on the second fixed frame 6. One end of the bidirectional lead screw 10 passes through the first fixed frame 5 and is fixedly mounted with a handwheel 12.

[0028] The centering mechanism is used to quickly and accurately position the Marshall specimen mold at the center of the workstation. During operation, the handwheel 12 is turned, which drives the double-acting screw 10 to rotate on the first fixed frame 5. Due to the thread design of the double-acting screw 10, the two screw nuts 11 installed on it will move inward or outward simultaneously when rotated (the direction depends on the direction of rotation). The movement of the screw nuts 11 is transmitted to the upper centering block 7 and the lower centering block 8 through the connecting block 9. One end of the upper centering block 7 and the lower centering block 8 moves with the connecting block 9, while the other end slides under the guidance constraint of the second fixed frame 6, thereby clamping or releasing the mold placed on the workstation and realizing the rapid centering and positioning of the mold.

[0029] like Figure 4 , Figure 5 As shown, both the upper centering block 7 and the lower centering block 8 are V-shaped, and the upper centering block 7 and the lower centering block 8 are installed in a staggered manner.

[0030] Preferably, rubber blocks can be embedded on the surfaces of the upper centering block 7 and the lower centering block 8 that contact the mold. This increases friction, ensures the clamping effect, protects the mold, and prevents rigid contact that could affect its subsequent use.

[0031] The V-shaped inclined surfaces formed inside the upper centering block 7 and the lower centering block 8 form four-point contact with the outer wall of the cylindrical mold (two points for each centering block). When the V-shaped inclined surfaces clamp the outer wall of the cylindrical Marshall specimen mold, the mold will be naturally guided to the intersection of the symmetrical center lines of the two upper centering blocks 7 and the lower centering block 8. Regardless of the mold diameter (which needs to be within the adjustment range of the V-block opening), the mold can be in the precise center position of the station (directly above the hydraulic ejector rod 2).

[0032] The upper centering block 7 and the lower centering block 8 are installed in a staggered manner (usually one is installed at a slightly higher position and the other at a slightly lower position) to avoid them being at the same height in the vertical direction, thereby preventing structural interference during clamping.

[0033] like Figure 4 , Figure 5 As shown, the limiting mechanism includes a threaded rod 15, which is rotatably mounted on the upper centering block 7. A threaded sleeve 16 is threadedly mounted on the threaded rod 15, and a lifting block 13 is fixedly mounted on the threaded sleeve 16. A pressing strip 14 is provided on the lifting block 13. An operating block 17 is fixedly mounted on the side of the threaded rod 15 away from the upper centering block 7.

[0034] The main function of the limiting mechanism is to press the upper end face (flange edge) of the mold to prevent the entire mold from being lifted upward when the hydraulic ejector rod 2 pushes the test piece upward, which would cause demolding failure or safety accidents.

[0035] During operation, rotating the operating block 17 causes the threaded rod 15 to rotate on the upper centering block 7 (the threaded rod 15 is usually rotated by bearings or bushings). Since the threaded sleeve 16 and the threaded rod 15 are threadedly engaged, rotating the threaded rod 15 will drive the threaded sleeve 16 to move the lifting block 13 up and down along the axial direction (vertical direction) of the threaded rod 15. When the lifting block 13 moves downward, the pressing strip 14 on it will also descend until it presses against the demolding pad placed on the upper end face of the mold or directly presses against the flange edge of the mold. Rotating the operating block 17 upward will lift the pressing strip 14 and release the mold.

[0036] The lifting block 13 coincides with the upper centering block 7 in the vertical direction, and the pressing strip 14 is embedded on the two sides of the lifting block 13 facing inward. The pressing strip 14 can directly contact the upper surface of the mold.

[0037] The pressure strips 14 are embedded on both sides of the inner side of the lifting block 13 (facing the center of the mold) to form a downward pressing structure similar to a "V-shaped frame". When the lifting block 13 descends, the two parallel pressure strips 14 can stably and evenly press the upper end face of the mold (usually the flange edge) or the two sides of the demolding pad, providing balanced downward pressure and effectively preventing the mold from moving upward during demolding. The pressure strips 14 directly contact the upper surface of the mold to ensure effective transmission of the clamping force.

[0038] Preferably, the thickness of the pressure strip 14 should be the same as or similar to the thickness of the mold to ensure that the pressure strip 14 does not obstruct the movement path of the Marshall specimen.

[0039] like Figure 4 , Figure 5 As shown, two guide rods 18 are fixedly installed on the upper centering block 7, and the lifting block 13 is slidably installed on the two guide rods 18. The two guide rods 18, which are perpendicular to the upper centering block 7, are fixedly installed on the upper centering block 7. They pass through the corresponding guide holes on the lifting block 13. When the rotating operating block 17 drives the lifting block 13 to rise and fall, the guide rods 18 play a key guiding role to ensure that the lifting block 13 only performs a strict vertical lifting and falling movement and does not deflect or jam.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A Marshall specimen demolding machine, comprising a machine body (1), wherein a hydraulic ejector rod (2) is provided on the machine body (1), characterized in that, A sliding plate (3) is slidably installed on the body (1). The sliding plate (3) has two workstations. Both workstations of the sliding plate (3) are equipped with a centering mechanism and a limiting mechanism. Both workstations of the sliding plate (3) have an exposed groove (4). The exposed groove (4) is adapted to the hydraulic ejector rod (2).

2. The Marshall specimen demolding machine according to claim 1, characterized in that, The centering mechanism includes a first fixed frame (5) and a second fixed frame (6). The first fixed frame (5) and the second fixed frame (6) are both fixedly mounted on the sliding plate (3). A bidirectional lead screw (10) is rotatably mounted on the first fixed frame (5). Two lead screw nuts (11) are threadedly mounted on the bidirectional lead screw (10). A connecting block (9) is fixedly mounted on each of the two lead screw nuts (11). An upper centering block (7) and a lower centering block (8) are fixedly mounted on the two connecting blocks (9). The other ends of the upper centering block (7) and the lower centering block (8) are slidably mounted on the second fixed frame (6). One end of the bidirectional lead screw (10) passes through the first fixed frame (5) and is fixedly mounted with a handwheel (12).

3. A Marshall specimen demolding machine according to claim 2, characterized in that, Both the upper centering block (7) and the lower centering block (8) are V-shaped, and the upper centering block (7) and the lower centering block (8) are installed in a staggered manner.

4. A Marshall specimen demolding machine according to claim 2, characterized in that, The limiting mechanism includes a threaded rod (15), which is rotatably mounted on the upper centering block (7). A threaded sleeve (16) is threadedly mounted on the threaded rod (15), and a lifting block (13) is fixedly mounted on the threaded sleeve (16). A pressing strip (14) is provided on the lifting block (13). An operating block (17) is fixedly mounted on the side of the threaded rod (15) away from the upper centering block (7).

5. A Marshall specimen demolding machine according to claim 4, characterized in that, The lifting block (13) coincides with the upper centering block (7) in the vertical direction. The pressing strip (14) is embedded on both sides of the lifting block (13) facing inward. The pressing strip (14) can directly contact the upper surface of the mold.

6. A Marshall specimen demolding machine according to claim 4, characterized in that, Two guide rods (18) are fixedly installed on the upper centering block (7), and the lifting block (13) is slidably installed on the two guide rods (18).

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