Scrap steel stock yard

Abstract

The utility model relates to a waste steel yard, and belongs to the technical field of comprehensive utilization of renewable resources. Comprising a material receiving system, a conveying and unloading system and a storing and taking system, and further comprises dust suppression devices arranged on the material receiving system and the storing and taking system correspondingly. The material receiving system comprises an unloading device, an unloading workshop, a stock bin and a feeding machine, the conveying and unloading system comprises conveying equipment, an equipment walking platform and unloading equipment, and the storing and taking system comprises material taking equipment, an outer enclosure structure, a retaining wall, a material storage grid, a charging container and a weighing device. Incoming scrap steel is unloaded in the material receiving system, transferred into the material storage grids through the conveying equipment and the unloading equipment for classified storage, transferred into the material loading container through the material taking equipment for weighing, and finally conveyed out of a material yard through the conveying equipment. The whole process of classification treatment and transfer of the scrap steel is intelligent and mechanical, the cost is low, and safety and reliability are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of comprehensive utilization of scrap steel regeneration resources and relates to a scrap steel material yard. Background Art

[0002] As one of the two most important raw materials in the steel industry, scrap steel plays a vital role in the future development of the steel industry. It may even replace iron ore and become an important raw material and important strategic resource for the development of the world's steel industry.

[0003] At present, there are many problems in the scrap steel processing process, such as backward technology, low degree of mechanization and intelligence, and high cost, which seriously restrict the high-quality development of the scrap steel industry.

[0004] First, the current mechanization level of scrap steel processing facilities is low, resulting in backward processing technology and low operating efficiency; second, scrap steel processing and storage sites rely on cars to circulate and transport scrap steel between steel mills and electric furnace plants, resulting in low site utilization and high overall costs; finally, most scrap steel processing work relies on manual labor, and the various processes are independent and unconnected, with poor intensiveness and a low level of intelligence.

[0005] In addition, the current scrap steel processing process still has problems of high safety risks and great environmental pressure. For example, scrap steel is usually large in size. If it is not stacked properly, it is easy to cause accidents such as tipping over and crushing. The sharp edges and thorns of scrap steel can easily cause harm to recycling personnel. Scrap steel usually contains harmful substances such as copper, lead, zinc, and cadmium. If it is not handled properly, it may cause harm to the environment and human health. Scrap steel is highly oxidizing and is prone to spontaneous combustion or explosion under high temperature, humidity, contact with oxygen and other conditions, causing fire accidents. In the process of processing scrap steel, the heavy metal elements contained in the scrap steel may penetrate into the soil, water sources and other environments, causing pollution to the environment, etc.

[0006] The above-mentioned scrap steel processing processes and technical systems can no longer meet the growing development requirements of the scrap steel industry, are not conducive to the high-quality, efficient and modern development of the market, and are not in line with the development trends and trends of the industry. Therefore, it is urgent to break through the technical bottlenecks in the scrap steel industry.

[0007] The utility model provides a scrap steel material yard capable of realizing full-process integrated processing of scrap steel, which has a very broad application prospect in the scrap steel industry in the future. Utility Model Content

[0008] In view of this, the purpose of the utility model is to provide a scrap steel yard to realize the intelligent and mechanized whole process of scrap steel processing with low cost and safety and reliability.

[0009] In order to achieve the above object, the utility model provides the following technical solutions:

[0010] A scrap steel yard comprises a receiving system and a storage and retrieval system arranged in sequence from top to bottom, and a conveying and unloading system arranged inside the storage and retrieval system, and the scrap steel yard further comprises dust suppression devices respectively arranged on the receiving system and the storage and retrieval system;

[0011] The material receiving system includes a material unloading workshop, and a car unloading device, a silo and a feeder arranged inside the material unloading workshop, wherein the car unloading device is connected to the feeder through the silo;

[0012] The dust suppression device is arranged above or at the side of the feeder.

[0013] Optionally, the conveying and unloading system includes a conveying device arranged below the feeder, and a unloading device arranged on the conveying device, and also includes an equipment running platform arranged below the conveying device, and the conveying device and the equipment running platform are arranged to extend in the same direction;

[0014] A track is provided on one side of the equipment walking platform close to the unloading equipment, and the track cooperates with the unloading equipment, and the unloading equipment walks on the track; the walking direction of the unloading equipment is the same as the extension direction of the conveying equipment and the equipment walking platform.

[0015] Optionally, the storage and retrieval system includes an outer protective structure, which is arranged outside the conveying and unloading system; the storage and retrieval system also includes a retrieval device arranged below the conveying and unloading system, and a retaining wall is arranged below the retrieval device, and the retaining wall separates a number of storage grids; a loading container is arranged on one side of the storage grid, and the retrieval device moves between the storage grid and the loading container, and the retrieval device transfers the scrap steel in the storage grid to the loading container.

[0016] The arrangement and number of retaining walls can be flexibly set to separate the storage grids to meet the needs of the processing flow.

[0017] The scrap steel on the conveying equipment is transported to the top of the storage grid. The unloading equipment moves on the track of the equipment's walking platform until it moves above the storage grid corresponding to the type of scrap steel. The scrap steel then automatically falls into the corresponding storage grid and is stacked in the storage grid.

[0018] The scrap steel stored in the storage grid is taken out by the material taking equipment and transferred to the loading container. The loading container moves along the fixed track and can move with the material taking equipment according to the type of scrap steel in the storage grid, so as to achieve the shortest transfer distance from the storage grid to the loading container.

[0019] Optionally, the outer enclosure structure is fully enclosed or semi-enclosed. For the fully enclosed form, a closed storage room can be selected, and the side walls of the storage room can be fully enclosed with wall skins, or with windbreak walls, windbreak boards or windbreak nets with a certain opening rate. The fully enclosed structure can avoid the impact of external wind dust and rain and snow weather, and stabilize the characteristics of the stored scrap steel; the semi-enclosed form is a structure with open side walls and enclosed ceilings, such as a storage shed plus a plant column structure.

[0020] Optionally, the dust suppression device is arranged around the storage grid.

[0021] Optionally, a weighing device is provided on the loading container, and the scrap steel transferred into the loading container is weighed by the weighing device.

[0022] Optionally, a running track matching with the loading container is provided at the bottom of the loading container, and the loading container moves on the running track along the moving direction of the material taking equipment, so as to achieve the shortest transfer distance from the material storage grid to the loading container.

[0023] Optionally, the material taking device may take the form of grabbing or lifting. Grabbing can be achieved by grabbing equipment, and lifting can be achieved by an electromagnetic bridge crane.

[0024] The beneficial effects of the utility model are:

[0025] (1) The new type of scrap steel material yard of the utility model realizes the intelligentization and mechanization of the whole process of scrap steel processing, and has the advantages of being green, environmentally friendly, safe, efficient and low-cost.

[0026] (2) The utility model reduces the parking area of ​​cars in the material yard, reduces the pressure of transportation logistics and improves the unloading efficiency through the unloading workshop and unloading device; realizes the transportation, unloading and storage of scrap steel through the conveying equipment and unloading equipment, reduces the transportation cost, avoids the multiple lifting and turnover of scrap steel, and improves the transportation efficiency and storage capacity per unit area; realizes intelligent material picking, loading and batching through unmanned material picking equipment.

[0027] (3) The whole process of the utility model greatly reduces the comprehensive cost of scrap steel processing. The whole process can be realized on-site unmanned operation, which greatly improves safety. A dust suppression device is set up to reduce environmental pressure.

[0028] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and will be apparent to those skilled in the art based on the following examination and research, or can be taught from the practice of the present invention to some extent. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be described in detail below in conjunction with the accompanying drawings, in which:

[0030] Figure 1 This is a schematic diagram of the material receiving system of Example 1;

[0031] Figure 2 Schematic diagram of the conveying and unloading system and the storage and retrieval system of Example 1;

[0032] Figure 3 This is a schematic diagram of the material receiving system of Example 2;

[0033] Figure 4 Schematic diagram of the conveying and unloading system and the storage and retrieval system of Example 2;

[0034] Figure 5 Schematic diagram of the conveying and unloading system and the storage and retrieval system of Example 3.

[0035] Reference numerals:

[0036] 1 receiving system, 11 unloading device, 12 unloading workshop, 13 feeder, 14 silo, 2 conveying and unloading system, 21 conveying equipment, 22 equipment walking platform, 23 unloading equipment, 3 storage and retrieval system, 31 retrieving equipment, 311 electromagnetic bridge crane, 312 grabbing equipment, 32 external protective structure, 321 storage room, 322 storage shed, 33 retaining wall, 34 storage grid, 35 loading container, 36 weighing device, 4 auxiliary system, 41 dust suppression device. DETAILED DESCRIPTION

[0037] The following describes the implementation of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. The following embodiments and the features in the embodiments can be combined with each other without conflict.

[0038] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present utility model. In order to better illustrate the embodiments of the present utility model, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0039] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "back" and the like indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0040] See also Figure 1 to Figure 5 , which is a scrap steel material yard, including a receiving system 1 and a storage and retrieval system 3 arranged in sequence from top to bottom, and a conveying and unloading system 2 arranged inside the storage and retrieval system 3, and also includes an auxiliary system 4, which is interspersed among the receiving system 1, the conveying and unloading system 2, and the storage and retrieval system 3. The scrap steel material yard of the utility model can realize unmanned operation and intelligent operation on site.

[0041] (1) Material receiving system

[0042] The receiving system 1 is used to complete the unloading and transfer of incoming scrap steel, that is, the receiving of scrap steel. The receiving system 1 includes a unloading workshop 12, and an unloading device 11, a silo 14 and a feeder 13 arranged inside the unloading workshop 12. The unloading device 11 is connected to the feeder 13 through the silo 14; a dust suppression device 41 of the auxiliary system 4 is arranged above or on the side of the feeder 13 to reduce dust in the unloading workshop 12.

[0043] The vehicles transporting the incoming scrap steel drive into the closed unloading workshop 12, park on the unloading device 11, and then automatically unload into the silo 14. The silo 14 can temporarily store some scrap steel. During the unloading process, the dust suppression device 41 is started to reduce the dust in the unloading workshop 12. Then, the scrap steel is transferred to the conveying and unloading system 2 by the feeder 13. From then on, the scrap steel is received, that is, automatically unloaded and transferred. The scrap steel does not need to be stored and piled on the ground, grabbed and hoisted in the middle, and the entire receiving process is mechanically automated.

[0044] The receiving system 1 is also provided with relevant equipment for scrap steel quality inspection to perform preliminary quality inspection on the incoming scrap steel.

[0045] (2) Conveying and unloading system

[0046] The conveying and unloading system 2 conveys the scrap steel from the receiving system 1 and dumps and stacks it into the storage and retrieval system 3.

[0047] The conveying and unloading system 2 is arranged in the upper part of the storage and retrieval system 3. The conveying and unloading system 2 includes a conveying device 21 arranged below the feeder 13, and a unloading device 23 arranged on the conveying device 21, and also includes an equipment walking platform 22 arranged below the conveying device 21 and the unloading device 23. The conveying device 21 and the equipment walking platform 22 are arranged to extend in the same direction; a track is arranged on the side of the equipment walking platform 22 close to the unloading device 23, and the track cooperates with the unloading device 23, and the unloading device 23 can move back and forth on the track of the equipment walking platform 22; the walking direction of the unloading device 23 is the same as the extension direction of the conveying device 21 and the equipment walking platform 22. The equipment walking platform 22 has a variety of sizes, which can be selected according to the actual process needs.

[0048] The scrap steel that has completed receiving is transferred from the feeder 13 of the receiving system 1 to the conveying equipment 21, and then transported to the storage and retrieval system 3 through the conveying equipment 21; the unloading equipment 23 on the conveying equipment 21 moves to the corresponding position of the storage and retrieval system 3 according to the type of the transported scrap steel, and then the scrap steel transported by the conveying equipment 21 is automatically dropped into the corresponding position of the storage and retrieval system 3 through the unloading equipment 23.

[0049] At least one conveying device 21 is provided, and at least one unloading device 23 is provided. A plurality of conveying devices 21 and unloading devices 23 may also be provided according to actual process requirements.

[0050] (3) Storage and retrieval system

[0051] The storage and retrieval system 3 is used for the storage, retrieval, loading and batching of scrap steel.

[0052] The storage and retrieval system 3 includes an outer protective structure 32, which is buckled on the outside of the conveying and unloading system 2, and also includes a material taking device 31 arranged below the conveying and unloading system 2. A retaining wall 33 is arranged below the material taking device 31. The retaining wall 33 is arranged in two ways: horizontal arrangement and vertical arrangement. The retaining wall 33 separates a number of storage grids 34. The length, width and number of each storage grid 34 are set according to actual needs; a loading container 35 is arranged on one side of the storage grid 34, and a weighing device 36 and a running track matched with the loading container 35 are arranged below the loading container 35; the material taking device 31 moves between the storage grid 34 and the loading container 35 to transfer the scrap steel in the storage grid 34 to the loading container 35. A weighing device 36 is arranged on the loading container 35, and a fixed track matched with it is arranged at the bottom of the loading container 35, and the loading container 35 can move on the fixed track.

[0053] A dust suppression device 41 of the auxiliary system 4 is arranged around the storage grid 34. In this embodiment, the dust suppression device 41 adopts a spray dust suppression method. According to actual process requirements, the scrap steel stored in the storage grid 34 is sprayed to suppress dust, which plays an environmental protection role.

[0054] The scrap steel on the conveying equipment 21 is transported to the top of the storage grid 34, and the unloading equipment 23 moves on the track of the equipment walking platform 22 until it moves above the storage grid 34 corresponding to the type of scrap steel. The scrap steel then automatically falls into the corresponding storage grid 34 and is stored in the storage grid 34.

[0055] The scrap steel stored in the storage grid 34 is picked up by the picking device 31 and transferred to the loading container 35. The loading container 35 moves along a fixed track and can move with the picking device 31 according to the type of scrap steel in the storage grid 34, thereby achieving the shortest transfer distance from the storage grid 34 to the loading container 35.

[0056] After the loading container 35 of the scrap steel is loaded, it is weighed and recorded by the weighing device 36, and then the scrap steel in the loading container 35 is transported to the outside of the storage and retrieval system 3 by the transportation equipment, thus completing the processing flow in the scrap steel yard.

[0057] The loading container 35 may be a scrap steel trough, a scrap steel transport vehicle compartment, or a scrap steel transport equipment receiving trough.

[0058] It is used to store different types of scrap steel, and the quantity is determined by the type of scrap steel, the stockpile volume, the batching process, etc. The types of stored materials are increased by increasing the number of retaining walls 33, the storage volume is increased by increasing the height of the retaining walls 33, and the processing process is improved by optimizing the layout of the retaining walls 33.

[0059] (4) Auxiliary system

[0060] The auxiliary system 4 includes a dust suppression device 41, and also includes a power supply device, a lighting device, a fire-fighting device, a ventilation device, a lighting device, a water supply and drainage device, and other devices, one or more of which are combined, and each device is selectively set according to the needs of the processing process. The dust suppression device 41, power supply device, lighting device, fire-fighting device, ventilation device, lighting device, water supply and drainage device are all common technical solutions in this field, and will not be repeated here.

[0061] Among them, the dust suppression device 41, the ventilation device and the water supply and drainage device are used to treat the dust, waste gas and waste water generated in the material yard, and the fire-fighting device plays a protective role against the potential fire hazards in the material yard; therefore, some devices of the auxiliary system 4 play a positive role in improving the safety and environmental protection of the material yard.

[0062] like Figure 1-2As shown in the figure, it is the first embodiment, a scrap steel yard, in addition to the above-mentioned receiving system 1, conveying and unloading system 2, storage and retrieval system 3 and auxiliary system 4, also includes the following different parts:

[0063] (1) Material receiving system

[0064] The scrap steel transported by vehicles that cannot self-unload drives into the closed unloading workshop 12 and parks on the unloading device 11. The unloading device 11 can be raised and lowered. By raising and lowering the unloading device 11, the scrap steel in the vehicle compartment is automatically unloaded into the silo 14, and the subsequent scrap steel receiving process is completed.

[0065] (2) Storage and retrieval system

[0066] In this embodiment, the outer protective structure 32 is in the form of a closed storage room 321. The side walls of the storage room can be fully enclosed with wall skins, or with windbreak walls, windbreak boards or windbreak nets with a certain opening rate. The fully enclosed structure can avoid the impact of external wind dust and rainy and snowy weather, and stabilize the characteristics of the stored scrap steel.

[0067] In this embodiment, the material taking device 31 is an electromagnetic bridge crane 311, and other types of cranes can also be used in the actual processing process.

[0068] Electromagnetic bridge crane 311 is a kind of lifting equipment widely used in various industrial occasions. It lifts molten metal and metal materials through the suction force generated by electromagnets. This crane is mainly composed of bridge, electromagnetic crane, operating mechanism and control system. The bridge is the main structure of the crane. It is composed of two parallel and interconnected steel rails to support and guide the movement of the crane; the electromagnetic crane is the core part of the crane. It lifts materials through the suction force generated by electromagnets; the operating mechanism is the mechanism that makes the crane move on the bridge. It is composed of motors, reducers, brakes and wheels; the control system is used to control various operations of the crane, such as lifting, moving, stopping, etc.

[0069] In this embodiment, the bridge of the electromagnetic bridge crane 311 is arranged across the storage room 321 above the storage grid 34. The electromagnetic crane is moved on the bridge to the top of the corresponding storage grid 34 through the operating mechanism, and the electromagnet of the electromagnetic crane lifts the scrap steel in the lower storage grid 34 into the loading container 35.

[0070] The driving modes of the electromagnetic overhead crane 311 in this embodiment include: manual driving, unmanned driving, manual remote control driving, etc.

[0071] like Figure 3-4 As shown in the figure, it is a second embodiment, a scrap steel yard, in addition to the above-mentioned receiving system 1, conveying and unloading system 2, storage and retrieval system 3 and auxiliary system 4, also includes the following different parts:

[0072] (1) Material receiving system

[0073] The vehicle transporting the incoming scrap steel has the function of automatic unloading. The vehicle drives into the unloading workshop 12 and parks on the unloading device 11. After the vehicle automatically unloads into the silo 14, the vehicle leaves. At this time, the unloading workshop 12 and the unloading device no longer have the function of automatic unloading.

[0074] (2) Storage and retrieval system

[0075] In this embodiment, the external protective structure 32 is a structure of a material storage shed 322 plus factory columns, that is, a partially enclosed structure with open side walls and enclosed ceiling.

[0076] The material taking device 31 is a gripping device 312, which is arranged on one side of the material storage grid 34 and moves between the material storage grid 34 and the loading device. The gripping device 312 has the following walking modes: wheeled, crawler, fixed cantilever, etc. The driving modes of the gripping device 312 include: manual driving, unmanned driving, manual remote control driving, etc.

[0077] like Figure 1 and Figure 5 , which is the third embodiment, a scrap steel yard, in addition to the above-mentioned receiving system 1, conveying and unloading system 2, storage and retrieval system 3 and auxiliary system 4, also includes the following distinguishing parts:

[0078] On the basis of the second embodiment, the storage shed 322 adopts an "arc-shaped" structural ceiling. The arc-shaped roof can provide better natural light and ventilation effects, and can also better utilize solar energy, reduce energy consumption, and improve the energy efficiency of the scrap steel yard.

[0079] The conveying device 21 adopts a single-side arrangement structure, so the installation platform of the conveying device 21 will be smaller and lower, which can reduce the manufacturing cost of the installation platform project.

[0080] In this embodiment, an electromagnetic bridge crane 311 is used, and the equipment walking platform 22 arranged above the electromagnetic bridge crane 311 is selected to be of a type with a longer length in the direction in which the crane bridge extends, so that it covers a wider material dropping area.

[0081] The new scrap steel yard of the utility model realizes the intelligent and mechanized whole process of scrap steel treatment, and has the advantages of green environmental protection, safety, high efficiency and low cost. The unloading workshop 12 and the unloading device 11 reduce the parking area of ​​cars in the yard, reduce the pressure of transportation logistics and improve the unloading efficiency; the conveying equipment 21 and the unloading equipment 23 realize the transportation, unloading and storage of scrap steel, reduce the transportation cost, avoid multiple lifting and turnover of scrap steel, improve the transportation efficiency and storage per unit area; the unmanned material taking equipment 31 realizes intelligent material taking, loading and batching. The whole process of the utility model greatly reduces the comprehensive cost of scrap steel treatment, and the whole process can realize unmanned operation on site, which greatly improves the safety. The dust suppression device 41 is set to reduce the pressure of environmental protection.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the utility model.

Claims

1. A scrap steel yard, comprising a receiving system (1) and a storage and retrieval system (3) arranged in sequence from top to bottom, and a conveying and unloading system (2) arranged inside the storage and retrieval system (3), characterized in that: The scrap steel yard further comprises dust suppression devices (41) respectively arranged on the receiving system (1) and the storage and retrieval system (3); The receiving system (1) comprises a discharge workshop (12), and an unloading device (11), a silo (14) and a feeder (13) arranged inside the discharge workshop (12); the unloading device (11) is connected to the feeder (13) via the silo (14); and the dust suppression device (41) is arranged above or on the side of the feeder (13).

2. The scrap steel yard according to claim 1, characterized in that: The conveying and unloading system (2) comprises a conveying device (21) arranged below the feeder (13), and a unloading device (23) arranged on the conveying device (21), and also comprises an equipment running platform (22) arranged below the conveying device (21), wherein the conveying device (21) and the equipment running platform (22) are arranged to extend in the same direction; A track is provided on one side of the equipment walking platform (22) close to the unloading device (23); the track cooperates with the unloading device (23), and the unloading device (23) walks on the track; the walking direction of the unloading device (23) is the same as the extension direction of the conveying device (21) and the equipment walking platform (22).

3. The scrap steel yard according to claim 1, characterized in that: The storage and retrieval system (3) comprises an outer protective structure (32), and the outer protective structure (32) is arranged outside the conveying and unloading system (2); the storage and retrieval system (3) also comprises a material taking device (31) arranged below the conveying and unloading system (2), and a retaining wall (33) is arranged below the material taking device (31), and the retaining wall (33) separates a plurality of storage grids (34); a loading container (35) is arranged on one side of the storage grid (34), and the material taking device (31) moves between the storage grid (34) and the loading container (35), and the material taking device (31) transfers the scrap steel in the storage grid (34) to the loading container (35).

4. The scrap steel yard according to claim 3, characterized in that: The outer protective structure (32) is in a fully enclosed form or a semi-enclosed form.

5. The scrap steel yard according to claim 3, characterized in that: The dust suppression device (41) is arranged around the material storage grid (34).

6. The scrap steel yard according to claim 3, characterized in that: The charging container (35) is provided with a weighing device (36).

7. The scrap steel yard according to claim 3, characterized in that: The bottom of the loading container (35) is provided with a running track which matches the loading container (35).

8. The scrap steel yard according to claim 3, characterized in that: The material taking device (31) takes materials in the form of grabbing or lifting.

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