Overload protection device of crane

Abstract

The utility model discloses an overload protection device of a crane, which comprises a winding drum mechanism and a lifting appliance, the winding drum mechanism comprises a speed reducer, one side of the speed reducer is an input end, the input end is provided with a driving motor, the other side of the speed reducer is provided with three output ends, and the three output ends are provided with a protection winding drum and two lifting winding drums; the lifting appliance is located below the winding drum mechanism, a movable pulley block matched with the lifting winding drum is installed at the top of the lifting appliance, and a protection mechanism matched with the protection winding drum is further arranged at the top of the lifting appliance; the movable pulley block comprises a mounting frame, a mounting groove is formed in the mounting frame, sliding holes are formed in the two sides of the mounting groove, a mounting shaft is arranged between the two sliding holes, the mounting shaft is vertically and slidably connected into the sliding holes, pressure sensors are mounted at the tops of the sliding holes, a limiting plate is fixedly connected to the end of the mounting shaft, and a plurality of movable pulleys are rotationally connected to the mounting shaft. The protection device can play a role in detecting and protecting overload, and overload operation of the crane is avoided.

Description

Technical Field

[0001] This utility model relates to the field of lifting equipment technology, and in particular to an overload protection device for a crane. Background Technology

[0002] A crane is a multi-action lifting machine that vertically lifts and horizontally moves heavy objects within a certain range. Different cranes have different rated lifting capacities. The safety of lifting operations can only be guaranteed when the weight of the object is lower than the rated lifting capacity. If the weight of the object exceeds the rated lifting capacity, safety accidents such as wire rope breakage and crane collapse are likely to occur. Therefore, overload protection devices need to be installed on the lifting equipment. Existing overload protection devices only have the function of detection and alarm. If the protection device fails to activate in time, the crane can still lift overweight objects, and safety cannot be guaranteed. Utility Model Content

[0003] The purpose of this invention is to provide an overload protection device for a crane, which can detect and protect against overload, thus preventing the crane from operating under overload conditions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an overload protection device for a crane, comprising a drum mechanism and a lifting device. The drum mechanism includes a reducer, with one side of the reducer serving as an input end and a drive motor installed thereon. The other side of the reducer has three output ends, each equipped with a protective drum and two lifting drums. The lifting device is located below the drum mechanism, and a movable pulley assembly matching the lifting drum is installed on the top of the lifting device. The lifting drum and the movable pulley assembly are connected by a lifting wire rope. A protective mechanism matching the protective drum is also installed on the top of the lifting device, and the protective drum and the protective mechanism are connected by a protective wire rope. The movable pulley assembly includes a mounting frame with a mounting groove. Sliding holes are provided on both sides of the mounting groove, and a mounting shaft is provided between two sliding holes. The mounting shaft is vertically slidably connected within the sliding holes. A pressure sensor is installed on the top of the sliding holes. A limit plate is fixedly connected to the end of the mounting shaft, and several movable pulleys are rotatably connected to the mounting shaft. The mounting shaft and the movable pulleys are located within the mounting groove.

[0005] Optionally, the protection mechanism includes a protection frame, which is fixedly connected to the lifting device. The protection frame has a hollow interior. A placement groove is provided at the connection point between the lifting device and the interior of the protection frame. The end of the protective wire rope passes through the protection frame and is placed inside the protection frame. A counterweight is fixedly connected to the end of the protective wire rope and is located in the placement groove. Limiting sliders are slidably connected to both sides of the protection frame. The limiting sliders pass through the mounting frame and are equipped with telescopic cylinders on the outside of the limiting sliders. The telescopic rod is fixedly connected to the lifting device.

[0006] Optionally, the inner side of the limiting slider is provided with a guide surface of inclined structure.

[0007] Optionally, the three output ends are evenly arranged on the reducer, with the protective drum installed at the middle output end and the lifting drum installed at the output ends on both sides.

[0008] Optionally, there are four movable pulley blocks arranged in a rectangular pattern, with two movable pulley blocks corresponding to each lifting drum, and the protection mechanism is located at the center of the four movable pulley blocks.

[0009] The overload protection device for cranes of this invention has the following advantages:

[0010] (1) When the lifting device is lifting an object, the mounting shaft slides upward along the sliding hole to apply pressure to the pressure sensor. If the pressure is lower than the set value, it means that the object is not overloaded and the lifting operation can be carried out normally. If the pressure is higher than the set value, it means that the object is overloaded. The controller restricts the rotation of the lifting drum and does not lift the object. At the same time, the protection mechanism fixes the protective wire rope to protect the wire rope from stress, reduce the load on the lifting wire rope, avoid the wire rope from breaking, and improve the safety of operation.

[0011] (2) The counterweight can keep the protective wire rope taut and prevent the wire rope from loosening and derailing.

[0012] (3) The installation of the hoisting drum, the protective drum, the movable pulley block and the protective mechanism can stabilize the center of gravity of the lifting device and improve its stability. Attached Figure Description

[0013] Figure 1 This is a structural diagram of the lifting device.

[0014] Figure 2 This is a schematic diagram of the drum mechanism.

[0015] Figure 3 This is a schematic diagram of the movable pulley system.

[0016] Figure 4 This is a schematic diagram showing the limit slider in the open state.

[0017] Figure 5 This is a schematic diagram showing the limit slider in the closed state. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] like Figures 1-5As shown, an overload protection device for a crane includes a drum mechanism and a lifting device 1. The drum mechanism includes a reducer 2, with an input end on one side and a drive motor 3 installed thereon. Three output ends are evenly distributed on the other side of the reducer 2. A protective drum 4 is installed at the middle output end, and lifting drums 5 are installed at the two side output ends. The drive motor 3 can drive the three drums to rotate synchronously. The lifting device 1 is located below the drum mechanism. Four movable pulley groups 6, matching the lifting drums 5, are installed on the top of the lifting device 1. The four movable pulley groups 6 are rectangularly distributed, with the left lifting drum 5 corresponding to the two left movable pulley groups 6, and the right lifting drum 5 corresponding to the two right movable pulley groups 6. The lifting drums 5 and the movable pulley groups 6 are connected by lifting wire ropes. The top of the lifting device 1 is also equipped with a protective mechanism 7 that matches the protective drum 4. The protective mechanism 7 is located at the center of the four movable pulley blocks 6. The protective drum 4 and the protective mechanism 7 are connected by a protective wire rope 16. The arrangement of the movable pulley blocks 6 and the protective mechanism 7 can stabilize the center of gravity of the lifting device 1 and improve the stability of the lifting device 1.

[0020] The movable pulley block 6 includes a mounting frame 8. The top of the mounting frame 8 has a mounting groove, and the two sides of the mounting groove have sliding holes 9. A mounting shaft 10 is arranged between the two sliding holes 9. Two limiting plates 11 are fixedly connected to the end of the mounting shaft 10. A limiting groove is formed between the two limiting plates 11. The limiting groove is vertically slidably connected in the sliding hole 9. A pressure sensor 12 is installed on the top of the sliding hole 9. Several movable pulleys 13 are rotatably connected to the mounting shaft 10. The mounting shaft 10 and the movable pulleys 13 are located in the mounting groove. The protective mechanism 7 includes a protective frame 14, which is fixedly connected to the top of the lifting device 1. The protective frame 14 has a hollow interior. A placement groove 15 is provided at the connection point between the lifting device 1 and the interior of the protective frame 14. The end of the protective wire rope 16 passes through the protective frame 14 and is placed inside the protective frame 14. A counterweight 17 is fixedly connected to the end of the protective wire rope 16 and is located in the placement groove 15. The counterweight 17 can keep the protective wire rope 16 taut and prevent the protective wire rope 16 from slackening and coming off the groove on the protective drum 4. Limiting sliders 18 are slidably connected to both sides of the protective frame 14. The limiting sliders 18 pass through the mounting frame 8. The inner side of the limiting sliders 18 is provided with an inclined guide surface, and the outer side of the limiting sliders 18 is provided with a telescopic cylinder 19. The telescopic rod is fixedly connected to the lifting device 1.

[0021] When the lifting device 1 lifts an object, the lifting drum 5 rotates, causing the lifting wire rope to rise, thereby causing the mounting shaft 10 to slide upward along the sliding hole 9 and apply pressure to the pressure sensor 12. If the pressure measured by the sensor is lower than the set value, it means that the object is not overloaded, the controller does not restrict the movement of the drum, and the crane can carry out the lifting operation normally. When the object is lifted or lowered, the protective drum 4 will also drive the protective wire rope 16 to rise or fall together, but the protective wire rope 16 does not share the weight of the lifting device 1. If the pressure measured by the sensor is higher than the set value, it indicates that the object is overloaded. At this time, the controller restricts the rotation of the hoisting drum 5, and the crane cannot lift the object. At the same time, the telescopic rod pushes the limit slider 18 inward, pressing the counterweight 17 into the placement groove 15. The guide surface can squeeze the counterweight 17 into the placement groove 15, reducing the connection difficulty. When the limit slider 18 completely presses down the counterweight 17, the protective wire rope 16 is connected to the lifting device 1. At this time, the protective wire rope 16 can share the weight of the lifting device 1, reduce the load on the hoisting wire ropes on both sides, avoid the wire rope breakage, and improve the safety of operation.

[0022] The embodiments described above are merely some embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the protection scope of this utility model.

Claims

1. An overload protection device for a crane, characterized in that: The system includes a drum mechanism and a lifting device. The drum mechanism includes a reducer with an input end on one side, where a drive motor is installed. The other side of the reducer has three output ends, each housing a protective drum and two lifting drums. The lifting device is located below the drum mechanism. A movable pulley assembly matching the lifting drums is installed on the top of the lifting device. The lifting drums are connected to the movable pulley assembly via a lifting wire rope. A protective mechanism matching the protective drum is also installed on the top of the lifting device, connected to the protective drum via a protective wire rope. The movable pulley assembly includes a mounting frame with mounting grooves. Sliding holes are formed on both sides of the mounting grooves. A mounting shaft is positioned between two sliding holes and slides vertically within the sliding holes. A pressure sensor is installed on the top of each sliding hole. A limit plate is fixedly connected to the end of the mounting shaft. Several movable pulleys are rotatably connected to the mounting shaft, which is located within the mounting groove.

2. An overload protection device for a crane as claimed in claim 1, characterised in that: The protective mechanism includes a protective frame, which is fixedly connected to the lifting device. The protective frame has a hollow internal structure. A placement groove is provided at the connection point between the lifting device and the inside of the protective frame. The end of the protective wire rope passes through the protective frame and is placed inside the protective frame. A counterweight is fixedly connected to the end of the protective wire rope, and the counterweight is located in the placement groove. Limiting sliders are slidably connected to both sides of the protective frame. The limiting sliders are set through the mounting frame. A telescopic cylinder is provided on the outside of the limiting slider. The telescopic rod is fixedly connected to the lifting device.

3. An overload protection device for a crane as claimed in claim 2, characterised in that: The inner side of the limit slider is provided with an inclined guide surface.

4. An overload protection device for a crane as defined in claim 1, characterized in that: The three output ends are evenly arranged on the reducer, with the protective drum installed at the middle output end and the lifting drum installed at the output ends on both sides.

5. An overload protection device for a crane as defined in claim 1, characterized in that: There are four movable pulley blocks arranged in a rectangular pattern. Each lifting drum corresponds to two movable pulley blocks, and the protection mechanism is located at the center of the four movable pulley blocks.

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