Device for grabbing bags with bulk materials

Abstract

The utility model relates to mechanical engineering, in particular to load-gripping devices, and can be used in loading and unloading operations for gripping and moving bags with bulk materials before unloading. The proposed technical solution ensures the adjustment of the frame position relative to the bag located at an angle to the horizon on a pallet. The device for gripping bags with bulk materials is characterized in that it contains a frame made in the form of three rectangular parallel metal plates, wherein the lower and middle plates are rigidly connected to each other by four posts made of a square profile pipe, and the upper one is connected to the middle one by means of chains, while on the upper plate there is a unit for attaching the bag gripper to a robotic manipulator, a control unit and a manifold connected to it with a group of pneumatic distributors, between the upper and middle plates there are two air cushions and four limit switches,connected to the control unit, between the middle and lower plates are installed pneumatic cylinders with toothed racks connected to two parallel shafts, on each of which are fixed four spikes, made in the form of a quadrant with the possibility of simultaneous counter rotation around the axis, also in the lower plate is mounted a laser rangefinder, while the limit switches and the laser rangefinder are connected to the control unit, and the air cushions and pneumatic cylinders - to the pneumatic distributor. 2 fig.,

Description

[0001] The utility model relates to mechanical engineering, in particular to load-gripping devices, and can be used in loading and unloading operations to grip and move bags with bulk materials before unloading.

[0002] To transport small disposable polyethylene / polypropylene bags to the unloader and unload them, either manual labor is mainly used, which is unacceptable for large-volume production, or complex and low-performance mechanisms and devices are used that are characterized by low efficiency, accuracy and failure resistance, and also require operator control.

[0003] For the production of bitumen and bitumen-polymer materials for thermal insulation of structures, roofing and waterproofing, self-adhesive roofing materials, and mastics, bulk raw materials (synthetic rubber, polymers, etc.) are often used. These materials are supplied in disposable polyethylene / polypropylene bags with a capacity of 50-58 liters and a weight of approximately 50 kg. The bags, stacked on a pallet, are picked up and fed to the unloading device and feed bins of the batching and mixing lines using lifting and transport mechanisms, pneumatic conveyors, and various conveyor systems. Hoists or overhead cranes are sometimes used to unload bags of bulk materials, transporting the bags to the unloading position (usually a receiving hopper or the loading hatch of a feed bin). However, this process is not automated and takes considerable time.When using linear palletizers, when the entire top layer of bags is captured, the accuracy of the operation decreases and the number of failures increases.

[0004] Robotic systems for unloading bags are known from literature and open sources and are being implemented in practice, but they are usually patented as single inventions and consist of a combination of known technologies (robots, machine vision systems, gripping devices, unloading stations, etc.).

[0005] For example, a robotic palletizing system (patent RU2813504, 2024) is known. It consists of a pallet magazine, multiple roller conveyors, a stand-mounted industrial robot including a base, an articulated arm unit attached to the base, a fork-type gripper connected to the articulated arm unit, a guard with a safety system, an automatic pallet feeding mechanism, and a stack formation and holding mechanism. Disadvantages of the system include its complex design, and the invention lacks a detailed description of the bag gripper, relying instead on a standard one.

[0006] A well-known project by the company "MetraRobotics" involves a robotic manipulator with a special gripper that moves bags to the unloading station and cuts them open above a rotary valve. The contents are then conveyed pneumatically to a weighing batcher and then loaded into a big bag.

[0007] Tesvel's renowned robotic system, based on the KUKA KR120 R3900 ultra K robot, is designed for depalletizing and unpacking polyethylene bags. Using machine vision, the robot determines the bag's position, adjusts the coordinate system, grasps the bag, transports it to the unpacking station, rips it open with circulating knives, and emptys the contents.

[0008] The Inspair system description mentions a robotic technology system (RTS) for layer-by-layer depalletizing and unpacking of bags containing granular products. The robotic manipulator removes a layer of bags from a pallet using a grabber, cuts them with circular knives, empties them into a loading hopper, shakes them before disposal, and transfers the empty bags to a container.

[0009] The main disadvantage of these technical solutions is the impossibility of tightly fitting the frame of the gripping device to a bag lying on a pallet at an angle, which can lead to a loose grip and the bag falling when moving to the unloader.

[0010] A robotic palletizing system (publication US20090028686, 2009) is known for receiving items from a conveyor and placing them on a pallet using a robot with an articulated arm. A lifting station with a lifting mechanism is located beneath the robot, which raises the item in the lifting zone to a height from which the robot can grasp it. A disadvantage of the system is the complexity of the design, due to the need for an additional lifting station with a lifting mechanism, and the inability to adjust the position of the gripping mechanism relative to the bag.

[0011] Also known is a load-gripping device primarily for bags (patent SU1720985, 1992), comprising a supporting element including a horizontal part and a movable element curved in a horizontal plane for grasping the load, located with a convexity from the vertical axis of symmetry, connected to the horizontal part of the supporting element, a double-arm gripping lever pivotally fixed at one end of the movable element, the lower end of one of the arms of which is curved, a bent link connected at one end to the double-arm gripping lever, and an element for connecting to a lifting mechanism, in order to increase the reliability of the gripping, it is provided with cheeks located parallel to each other and transverse to the horizontal part of the supporting element. A disadvantage of the load-gripping device is the impossibility of automatic operation and adjustment of the load gripper in space relative to the bag.

[0012] The well-known Solan-D system can be used as a prototype. It includes a column-type unloading robot with a toothed gripper, a machine vision system (2D camera and 3D scanner), and specialized AI software for analyzing bag placement and adjusting the gripper trajectory. The bag is transferred to a ripping knife attached to the receiving bin grate, after which the robot performs controlled shaking to completely empty it. However, the system also has several shortcomings, such as a vacuum adaptive gripper designed to grip only soft polyethylene bags, not fabric or paper ones, and the gripper's position adjustment is limited to horizontal adjustment, which is insufficient for gripping bags lying at an angle on a pallet.

[0013] The purpose of the utility model is to eliminate the shortcomings of analogues and the prototype.

[0014] The technical result consists in ensuring the adjustment of the frame position relative to the bag made of any material and located at an angle to the horizon on the pallet, its reliable fixation and guaranteed transfer to the receiving hopper of the unloader.

[0015] The stated problem is solved and the technical result is achieved by the fact that the device for gripping bags with bulk materials is characterized by the fact that it contains a frame made in the form of three rectangular parallel metal plates, wherein the lower and middle plates are rigidly connected to each other by four posts made of a square profile pipe, and the upper one is connected to the middle one by means of chains, while on the upper plate there is a unit for attaching the device for gripping bags to a robotic manipulator, a control unit and a manifold connected to it with a group of pneumatic distributors, between the upper and middle plates there are two air cushions and four limit switches connected to the control unit, between the middle and lower plates there are pneumatic cylinders with toothed racks connected to two parallel shafts, on each of which four spikes are fixed, made in the form of a quadrant with the possibility of simultaneous counter rotation around the axis,A laser rangefinder is also built into the bottom plate. The limit switches and laser rangefinder are connected to the control unit, while the air cushions and pneumatic cylinder are connected to the pneumatic valves. When the device is lowered onto a bag of bulk materials before gripping it, the angle of the middle plate relative to the top plate can be adjusted depending on the bag's position, thanks to the presence of chains and air cushions with adjustable air pressure between them.

[0016] Fig. 1 shows a general view of a device for gripping bags with bulk materials.

[0017] The device for gripping bags with bulk materials contains a frame 1 made in the form of three rectangular parallel metal plates, wherein the lower plate 2 and the middle plate 3 are rigidly connected to each other by four posts 4 made of a square profile pipe, and the upper plate 5 is connected to the middle plate 3 by means of chains 6, while on the upper plate 5 there is a unit 7 for attaching the device for gripping bags to a robotic manipulator, a control unit 8 and a manifold connected to it with a group of pneumatic distributors 9. Between the upper 5 and middle 3 plates there are two air cushions 10 and four limit switches 11 connected to the control unit 8.Between the middle 3 and the lower 2 plates, pneumatic cylinders 12 with toothed racks (not shown in the diagram) are installed, connected to two parallel shafts 13, on each of which four spikes 14 are fixed, made in the form of a quadrant with the possibility of simultaneous counter rotation around their axis on the shafts 13. Also, a laser rangefinder 15 is mounted in the lower plate 2, while the limit switches 11 and the laser rangefinder 15 are connected to the control unit 8, and the air cushions 10 and pneumatic cylinders 12 are connected to the pneumatic distributor 9. At the moment of lowering the device onto the bag with bulk materials before gripping it, it is possible to change the angle of inclination of the upper plate 5 to the middle 3 depending on the position of the bag due to the presence of chains 6 and air cushions 10 with regulated air pressure between them.

[0018] The bulk material bag grabber operates as follows.

[0019] The safe and automatic process of picking and transferring bags from a pallet to a bulk material unloader is performed by a robotic arm equipped with a bag-handling device. The robotic arm lifts the bag on 14 spikes above the unloader, where it is cut with circular knives. The bulk material then enters a conical hopper (not shown) and then a pneumatic conveying system (not shown).

[0020] The bag gripper is attached to the robotic manipulator via mounting unit 7. Before gripping a bag, the robotic manipulator moves the bag gripper toward the pallet containing the bags. At a predetermined height of frame 1, the device uses laser rangefinder 15 to locate the bag's edge and begin unloading according to the predetermined stacking pattern on the pallet. The bag's angle is irrelevant; the device is guaranteed to grip bags positioned at an angle of 20 degrees to the horizontal. Once the bag's edge is located, the robotic manipulator moves the bag gripper to the center of the bag to be unloaded. The robotic manipulator lowers the bag gripper onto the bag, with the air cushions 10 deflated.The bag gripper has three levels (three main plates), with the upper plate 5 and the central plate 3 connected by air cushions 10 and chains 6. This allows the frame 1 to assume a position in the plane close to the position of the bag itself when it is lowered by the robotic manipulator. The robotic manipulator lowers the bag gripper onto the bag until limit switches 11, of which there are four, are triggered. As soon as control unit 8 receives a signal from limit switches 11 about the contact of the middle plate 3 with the upper plate 5, a signal is sent from it to pneumatic distributor 9, which supplies compressed air under pressure to pneumatic cylinders 12, which rotate shafts 13 with spikes 14, which extend and pierce the bag. The bag can be made of various materials.The robotic manipulator then lifts the gripper with the bag above the pallet, simultaneously supplying compressed air to the air springs 10, which firmly secure the horizontal position of the entire frame 1, preventing it from swinging or falling. The gripper is then moved to the unloading area. After the bag is empty, the robotic manipulator moves the gripper to the empty bag drop area. The spikes 14 retract, and the bag falls into the storage area. The cycle then repeats.

[0021] An example of where this technical solution is being applied is at the Technonicol plant in Voskresensk, Moscow Region, Mineralnye Vody, and Chelyabinsk Region. Each of these plants has assembled the described device and uses it to grip and deliver bags of bulk materials to a debulker for the production of roofing, waterproofing, soundproofing, and thermal insulation materials and systems. Photographs of the completed device for gripping bags of bulk materials are shown in Fig. 2.

[0022] Thus, the proposed technical solution ensures the adjustment of the frame position relative to the bag located at an angle to the horizon on the pallet due to the introduction of a laser rangefinder and movable middle and lower plates on chains, reliable fixation of the bag and its guaranteed transfer to the receiving hopper of the unloader due to the design features of the frame, including air cushions with regulated air pressure.

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