Hanging eye for counterweight

Abstract

In some implementations, a counterweight assembly for a crane includes a plurality of counterweight slabs including first and second outer counterweight slabs, and one or more inner counterweight slabs sandwiched between inner lateral surfaces of the first and second outer counterweight slabs. A central slab of the one or more internal counterweight slabs includes a hanging eye embedded in a body of the central slab.

Description

Technical Field

[0001] The present invention relates generally to counterweights and, for example, to lifting eyes for counterweights. Background Art

[0002] Pipelayer is a machine for installing large, heavy-duty pipe sections in the ground and / or on the ground. During operation, the weight of the section of the pipelayer is extended laterally away from the chassis, engine and underframe (for example, the weight is suspended on the surrounding terrain) of the pipelayer. According to the weight of the section being lifted and the length of the boom, the pipelayer may suffer from potential tilting and instability. The counterweight positioned on the side opposite to the boom of the pipelayer offsets the weight of the section being lifted, to increase lifting capacity and prevent tipping.

[0003] In general, counterweights are installed on and removed from machines as needed. For example, different counterweights and / or counterweights of different sizes may be used on the same machine. Counterweights that have been bolted or welded to lifting hardware (e.g., lifting eyes or rings) have a greater inherent risk of failure caused by loose components or cracked welds and / or may require further machining or welding operations to add bolting or welding to the lifting hardware. Therefore, bolting or welding on lifting hardware may be less robust (e.g., lower strength), less secure, more prone to failure, and higher cost.

[0004] The system of the present invention solves one or more of the problems set forth above and / or other problems in the art. Summary of the invention

[0005] A counterweight assembly for a crane comprises: a plurality of counterweight slabs, including: first and second outer counterweight slabs; and one or more inner counterweight slabs sandwiched between inner lateral surfaces of the first and second outer counterweight slabs, wherein a center slab of the one or more inner counterweight slabs comprises a lifting eye embedded in a body of the center slab.

[0006] In some implementations, a counterweight slab having a body for a crane includes: a first lateral surface; a second lateral surface that faces away from the first lateral surface; a side surface that connects the first lateral surface and the second lateral surface together; and a lifting eye embedded in the body, wherein the lifting eye includes an opening aligned with an axis parallel to the side surface.

[0007] In some implementations, a method of manufacturing a counterweight slab for a crane includes: cutting a profile of the counterweight slab from a larger steel slab using a plasma torch, a laser, or a water jet, wherein the profile corresponds to the shape of a first lateral surface of a body of the counterweight slab, and wherein the body further includes: a second lateral surface that faces away from the first lateral surface; a lateral surface that connects the first lateral surface and the second lateral surface together; and a lifting eye embedded in the body. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a diagram of an example crane described herein.

[0009] Figure 2A is a perspective view of an example first counterweight assembly described herein.

[0010] Figure 2B is a perspective view of an example second counterweight assembly described herein.

[0011] Figure 3A is an elevation view of an example center counterweight plate blank of the first counterweight assembly described herein.

[0012] Figure 3B is an elevation view of an example center counterweight plate blank of the second counterweight assembly described herein.

[0013] Figure 4A is an enlarged view of a lifting eye portion of an exemplary center counterweight slab of the first counterweight assembly described herein.

[0014] Figure 4B is an enlarged view of a lifting eye portion of an exemplary center counterweight slab of the second counterweight assembly described herein.

[0015] Figure 5 is a flow chart of an example method of making the counterweight slabs described herein. DETAILED DESCRIPTION

[0016] The present invention relates to a counterweight applicable to any crane. The term "crane" may refer to any machine that performs a lifting operation associated with an industry such as mining, construction, farming, transportation or other industry. For example, a crane may be a pipelayer, an earthmoving machine (e.g., a crawler tractor or a wheel loader) and / or other machine.

[0017] Figure 1 is a diagram of an exemplary crane described herein. For example, Figure 1 A front view of the mobile pipelayer 10 is shown. Figure 1 As shown, pipelayer 10 includes a chassis 12, a pair of drive tracks 14 engaging the ground, a power source 15 (e.g., an internal combustion engine), an operator's cab 16, a counterweight 18 (e.g., a movable counterweight assembly) mounted on chassis 12, and a crane assembly 20 mounted on chassis 12 opposite counterweight 18. Pipelayer 10 defines a longitudinal axis oriented in the plane of the page from a front end (facing the viewer) to a rear end (facing away from the viewer).

[0018] Crane assembly 20 includes boom 22 and winch system 24, which is configured to drive the lifting operation of pipelayer 10. Boom 22 includes a pair of legs (e.g., front legs 26A and rear legs 26B), which can be spaced apart and independently hinged to chassis 12 at the proximal end. Legs 26A-B extend away from chassis 12 and are connected together at boom tip 28. Winch system 24 includes winch 30 and first group of lifting cables 32 extending from winch 30. First lifting cables 32 are connected to a series of pulleys or sheaves (e.g., first pulley 34 and second pulley 36) to raise and lower boom 22.

[0019] The winch system 24 includes a terminal connector (e.g., a grapple 38) to couple the crane assembly 20 to an object being lifted (e.g., a pipe 90). The winch system 24 includes a second set of lifting cables 40 extending from the winch 30. The second lifting cables 40 are coupled to a series of pulleys or sheaves (e.g., a third pulley 42 and a fourth pulley 44) to raise and lower the grapple 38.

[0020] As mentioned above, Figure 1 is provided as an example. Other examples may differ from those in combination with Figure 1 For example, in addition to a mobile pipelayer, aspects of the present invention may be implemented in any crane having a crane assembly 20 .

[0021] Figure 2A is a perspective view of an example first counterweight assembly 200A described herein. Figure 2B It is a perspective view of example second counterweight assembly 200B described herein. The size, shape and weight of the first and second counterweight assemblies 200A / B are different, and are configured to realize with machines of different sizes. For example, the first counterweight assembly 200A is used for relatively large machines (for example, PL83 and PL87 type pipelayers), and the second counterweight assembly 200B can be used for relatively small machines (for example, PL72 type pipelayers).

[0022] Each counterweight assembly 200A / B includes a plurality of counterweight blanks or plates. The individual counterweight blanks of each counterweight assembly 200A / B can be assembled together (e.g., bolted or welded) into a combined block. Each counterweight assembly 200A / B includes a first outer counterweight blank (e.g., front blank 202A / B) and a second outer counterweight blank (e.g., rear blank 204A / B). Each counterweight assembly 200A / B also includes one or more inner counterweight blanks (e.g., 5 inner blanks, such as inner blanks 206A / B, 208A / B, 210A / B, 212A / B, 214A / B). In some examples, each counterweight assembly may include, but is not limited to, 1 to 5 inner blanks, such as 1, 2, 3, 4, or 5 inner blanks. For example, for an odd number of inner blanks, such as 1, 3, or 5 inner blanks (such as 206A / B, 208A / B, 210A / B, 212A / B, 214A / B), the counterweight assembly 200A / B may include, but is not limited to, 1 to 5 inner blanks, such as 1, 2, 3, 4, or 5 inner blanks. For example, for an odd number of inner blanks, such as 1, 3, or 5 inner blanks (such as 204A / B, 214A / B), the counterweight assembly 200A / B may include, but is not limited to, 1 to 5 inner blanks, such as 1, 2, 3, 4, or 5 inner blanks. Figure 2A and 2B ), the inner plate blank 210A / B is centered relative to the remaining plates, and therefore may also be referred to herein as the "center plate blank." In some examples, all plates of the counterweight assembly 200A / B may be formed of the same material. The lifting eye 201A / B is defined on the center plate blank 210A / B, as described in more detail herein.

[0023] In some examples, the center slab 210A / B may be formed of a different material than the other slabs. For example, the non-center slabs (e.g., the outer slabs 202A / B, 204A / B and the inner slabs 206A / B, 208A / B, 212A / B, 214A / B) may be formed of a low-grade steel material (e.g., pebble plate), which may include ballast or counterweight material as a low-grade byproduct from steel mill processing. On the other hand, the center slab 210A / B may be formed of a relatively higher grade steel material (e.g., a steel grade that exhibits one or more enhanced properties (e.g., yield strength and / or ultimate strength), the enhanced properties being greater than the corresponding properties of the above-mentioned low-grade steel material). For example, the higher grade steel material of the center slab 210A / B (including the lifting eye 201A / B) may support 2x load without plasticity (e.g., 2x increase in yield strength) and / or may support 3x load without failure (e.g., 3x increase in ultimate strength) compared to the low-grade steel material of the non-center slab. The higher grade steel of the center slab 210A / B compared to the other slabs results in an improvement in the quality (e.g., slab solidity and / or slab strength) of the center slab 210A / B, which is particularly important when the lifting eye 201A / B is defined on the center slab 210A / B. For example, the improved quality of the higher grade steel of the center slab 210A / B can give the lifting eye 201A / B additional strength, solidity, and safety compared to the lower grade steel of the other slabs. Likewise, the improved quality of the higher grade steel of the center slab 210A / B can give the lifting eye 201A / B additional strength, solidity, and safety compared to welding or bolting on the lifting device, which can introduce inherent failure risks caused by additional components (e.g., via cracked welds or loose attachments).

[0024] The internal counterweight slab is sandwiched between the internal lateral surface or face 216A / B of the front slab 202A / B and the internal lateral surface or face 218A / B of the rear slab 204A / B. Each counterweight assembly 200A / B includes a mounting structure 260A / B configured to engage with a corresponding structure on the pipelayer 10. Each counterweight assembly 200A / B can be installed on the pipelayer 10, wherein the front slab 202A / B is closest to the front end, the rear slab 204A / B is closest to the rear end, and the internal slabs 206A / B, 208A / B, 210A / B, 212A / B, 214A / B are stacked from the front end to the rear end along the longitudinal axis of the pipelayer 10.

[0025] The outer lateral surface or face 220A / B of the front slab 202A / B may be a front surface configured to face the forward direction of the pipelayer 10. Similarly, the outer lateral surface or face 222A / B of the rear slab 204A / B may be a rear surface configured to face the opposite direction of the pipelayer 10.

[0026] As mentioned above, Figure 2A -B is provided as an example. Other examples can be combined with Figure 2A -Different from what is described in B.

[0027] Figure 3A is a front view of an example center plate 210A of the first counterweight assembly 200A described herein. Figure 3B is a front view of an example center plate blank 210B of the second counterweight assembly 200B described herein.

[0028] Note that, except for the lifting eyes 201A / B defined on the center slab 210A / B, the non-center slabs (e.g., outer slabs 202A / B, 204A / B and inner slabs 206A / B, 208A / B, 212A / B, 214A / B) can be substantially identical to the center slab 210A / B.

[0029] Common Reference Figure 3A -B, the body 224A / B of the center plate blank 210A / B can be L-shaped (e.g., an inverted L-shape). The body 224A / B includes a first lateral surface 242A / B (e.g., a lateral surface facing forward), a lateral surface facing away from the first lateral surface (e.g., oriented in the Figure 3A -B) and a second lateral surface 250A / B (e.g., a rearward-facing lateral surface) of the body 224A / B, and a lateral surface 226A / B extending around the periphery of the body 224A / B. The lateral surface 226A / B connects the first lateral surface 242A / B and the second lateral surface 250A / B together. In some examples, all slabs of the counterweight assembly 200A / B can have the same thickness (e.g., along the lateral surface 226A / B). For example, the thickness of the center slab 210A / B can be equal to the thickness of all other slabs. In some examples, the thickness of at least one slab can be different from the thickness of one or more other slabs. For example, the thickness of the center slab 210A / B can be different from (e.g., greater than or less than) the thickness of one or more other slabs (e.g., different from all non-center slabs).

[0030] Common Reference Figure 3A-B, first lateral surface 242A / B comprises outer edge 228A / B, inner edge 230A / B, top edge 232A / B and bottom edge 234A / B.Compared with inner edge 230A / B, outer edge 228A / B can be larger from the distance of pipelayer 10.Inner edge 230A / B has step 236A / B that limits upper part 238A / B and lower part 240A / B.Upper part 238A / B can be wider than lower part 240A / B.Compared with lower part 240A / B, upper part 238A / B can be larger from the distance of ground.Top edge 232A / B connects outer edge 228A / B and upper part 238A / B.Bottom edge 234A / B connects outer edge 228A / B and lower part 240A / B.

[0031] In some examples, one or more dimensions of the body 224A / B (e.g., the depth and / or width of the profile burned into the outside edge 228A / B of the side surface 226A / B) can be configured to accommodate the bundling of the counterweight assembly 200A / B with a handling specification (e.g., 4 inch by 6 inch material) to allow for handling with forks. This represents an improvement over standard wooden pallets used in internal assembly production plants and inventory storage yards, and can provide benefits over rigging for end users who wish to manipulate the counterweight assembly 200A / B with forks, or as a practical way to keep the counterweight assembly 200A / B off the ground when stored in the yard.

[0032] Reference Figure 3A , the step 236A is perpendicular to the upper portion 238A and the lower portion 240A of the inner edge 230A. Figure 3B , the step 236B is inclined to the upper portion 238B and the lower portion 240B of the inner edge 230B.

[0033] Common Reference Figure 3A -B, the center slab 210A / B may include a recess 254A / B in the side surface 226A / B (e.g., along the upper portion 238A / B). The recess 254A / B may be at least partially defined by the slabs surrounding the center slab 210A / B (e.g., the inner slabs 208A / B and 212A / B). In some examples, a machine system device (e.g., a radio frequency identification (RFID) tag) may be disposed in the recess 254A / B. For example, the recess 254A / B may be configured to shield or protect the RFID tag. As described above, Figure 3A -B is provided as an example. Other examples may differ from combining Figure 3A - as described by B.

[0034] Figure 4Ais an enlarged view of a lifting eye portion of an exemplary center counterweight plate blank 210A of the first counterweight assembly 200A described herein. Figure 4B is an enlarged view of a lifting eye portion of an exemplary center counterweight plate blank 210B of the second counterweight assembly 200B described herein.

[0035] Common Reference Figure 4A -B, the lifting eye 201A / B includes a first and a second lateral surface and a side surface, which can be respectively continuous with the first lateral surface 242A / B, the second lateral surface 250A / B and the side surface 226A / B of the main body 224A / B of the center plate blank 210A / B. For example, the lifting eye 201A / B is arranged along the axis 244 (e.g., parallel to Figure 3A 226A / B) from the first lateral surface 242A / B to the second lateral surface 250A / B can be equal to the thickness of the body 224A / B of the center slab 210A / B (e.g., along the side surface 226A / B). In some examples, the thickness of the body 224A / B and / or the eye 201A / B can be about 3 inches or more (e.g., about 3 inches). In some other examples, the thickness of the eye 201A / B can be different from (e.g., less than) the thickness of the body 224A / B, such that one or more lateral surfaces of the eye 201A / B can be recessed relative to corresponding surfaces of the first and second lateral surfaces of the body 224A / B.

[0036] The lifting eye 201A / B may have a circular shape (e.g., a U-shape, such as an inverted U-shape). The lifting eye 201A / B extends beyond the top edge 232A / B of the body 224A / B by a first distance d1. The first distance d1 may be about 3 inches or more, for example, in the range of about 3 inches to about 5 inches (e.g., about 4 inches). The lifting eye 201A / B includes an opening 246 aligned with the axis 244. In some examples, the opening 246 may extend between the first lateral surface 242A / B and the second lateral surface 250A / B (e.g., from the first lateral surface 242A / B to the second lateral surface 250A / B). In some examples, the opening 246 is shaped to match the shape or contour of the lifting eye 201A / B (e.g., along the side surface 226A / B) so that the lifting eye 201A / B has a fixed distance between the opening 246 and the side surface 226A / B.

[0037] A second distance d2 (e.g., the width of the opening 246) and a third distance d3 (e.g., the height of the opening 246) associated with the opening 246, which are perpendicular to the second distance d2, can be sized to accommodate a shackle size typically used on a work site with heavy equipment. For example, the width and height can be equal to each other to be optimized to receive a round pin (e.g., a clevis pin 248) through the opening 246. For example, the second distance d2 and / or the third distance d3 can be about 2.25 inches or greater, such as in the range of about 2.25 inches to about 2.75 inches (e.g., 2.5 inches). When the second distance d2 and the third distance d3 are greater than 2.25 inches, the opening 246 is able to accommodate a clevis pin 248 (shown in phantom) corresponding to a 35-ton shackle (e.g., a 2-inch nominal size G-209 / S-209 screw pin anchor shackle with a 35-ton working load limit). It is noteworthy that the minimum size of the opening 246 of the lifting eye 201A / B described herein is to accommodate shackle sizes that are commonly used on work sites with heavy equipment (e.g., up to 35 tons). In some examples, an oversized shackle may be required in order to fit the U-shaped clevis around the lifting eye 201A / B. For example, based on the thickness of the body 224A / B and / or the lifting eye 201A / B (e.g., 3 inches or greater as described above), a 35-ton shackle may be required to fit around the lifting eye 201A / B, and therefore, the opening 246 in the lifting eye 201A / B may be sized to accommodate a clevis pin 248 corresponding to a 35-ton shackle, even though a smaller shackle and corresponding clevis pin having a 5-ton working limit would be sufficient.

[0038] The lifting eye 201A / B includes a chamfer 252 around the opening 246 (e.g., around the outside edge of the opening 246, which may also be referred to herein as the "inside edge of the lifting eye"). The chamfer 252 can prevent or at least reduce wear of a lifting device (e.g., a strap) engaged with the lifting eye 201A / B caused by direct contact (e.g., friction) between the lifting device and the edge of the opening 246. In some examples, based on the weight of the counterweight assembly 200A / B and / or the type of equipment available at the construction site, the lifting device can include one or more straps, chains, or shackles to be engaged with the lifting eye 201A / B. In some examples, the chamfer can be omitted.

[0039] As mentioned above, Figure 4A -B is provided as an example. Other examples may differ from combining Figure 4A - as described by B.

[0040] Figure 5is a flow chart of an example method 500 for manufacturing a counterweight slab (e.g., a center slab 210A / B) described herein. At 510, the method 500 includes cutting the contour of a counterweight slab from a larger steel slab using a plasma torch (which may also be referred to herein as "combustion," "slab combustion," or "flame cutting"), a laser, or a water jet. In order to cut the center slab 210A / B by combustion, the size and shape of the larger steel slab needs to be determined based on the contour of the center slab 210A / B including the lifting eye 201A / B. For example, the larger steel slab may include 2 or more nested profiles. Because material is cut from the larger steel slab to form the lifting eye 201A / B, some material around the lifting eye 201A / B is wasted. To reduce waste, the distance d1 can be kept to a minimum value that can achieve the desired size range of the above-mentioned opening 246.

[0041] The profile may correspond to the shape of a lateral surface (e.g., first lateral surface 242A / B) of the body 224A / B of the center slab 210A / B, including the eye 201A / B. For example, the profile in the body 224A / B may include an outer shape (e.g., corresponding to the lateral surface 226A / B) and an inner shape (e.g., corresponding to the opening 246). For example, burning the profile at 510 may include, first, burning the outer shape of the body 224A / B, and second, piercing the eye 201A / B at a location within the inner edge of the eye and burning the inner shape, or vice versa. Thus, the eye 201A / B is integral with the entirety of the center slab 210A / B (it may also be referred to herein as being "integral" with or "embedded in" the center slab 210A / B). In other words, the center slab 210A / B including the eye 201A / B may be implemented as a single solid piece. For example, the lifting eye 201A / B can be part of or integral with the body 224A / B of the center slab 210A / B without being bolted or welded to the body 224A / B. In contrast to some potential alternative configurations that may be known in the industry, the lifting eye 201A / B of the present invention is manufactured together (e.g., in a single step or operation) with the center slab 210A / B (e.g., via combustion). For example, cutting the contour of the center slab 210A / B can include forming the opening 246. Therefore, in contrast to possible alternative configurations, the lifting eye 201A / B of the present invention is not attached to the center slab 210A / B in a secondary operation (e.g., by welding, rods, pins and / or hinges).

[0042] At 520, method 500 includes forming one or more chamfers 252 in the lifting eye 201A / B. For example, one or more chamfers 252 can be formed by machining a counterweight slab (e.g., a center slab 210A / B) with a machine tool. For example, the machine tool can be a milling machine, a chamfering tool, a deburring tool, a beveling tool, or a drilling tool. The corresponding dimensions of the one or more chamfers 252 can correspond to the tool of the machine tool. In some examples, the one or more chamfers 252 can be formed by combustion (e.g., according to the same process described above for cutting the contour of the counterweight slab). For example, the angle of a plasma torch, a laser, or a water jet can be selected to cut the desired angle of one or more chamfers 252. In some examples, one or more chamfers 252 can be omitted, as described above.

[0043] In some examples, the method 500 may include one or more additional blocks. For example, a counterweight slab includes a flatness specification to ensure that the individual slabs are stacked correctly together. Even when the flatness specification is wide, there may be situations where a secondary operation is required in the event of deformation.

[0044] As mentioned above, Figure 5 is provided as an example. Other examples may differ from those in combination with Figure 5 described. Figure 5 Example blocks of method 500 are shown, but in some implementations, method 500 may include Figure 5 Additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in. Additionally or alternatively, two or more blocks of method 500 may be performed in parallel.

[0045] Industrial Applicability

[0046] Counterweight can be associated with a crane such as a pipelayer to offset the weight of the object being lifted, thereby increasing lifting capacity and preventing tipping. For example, during operation, the pipelayer can extend the weight of the pipeline segment laterally away from the chassis, engine and underframe of the pipelayer (for example, the weight is suspended on the surrounding terrain). According to the weight of the section being lifted and the length of the boom, the counterweight can move to change the center of gravity of the pipelayer, thereby further resisting possible tilting and instability.

[0047] In general, counterweights are installed on and removed from machines as needed. For example, different counterweights and / or counterweights of different sizes may be used on the same machine. Counterweights that have been bolted or welded to lifting hardware (e.g., lifting eyes or rings) have a greater inherent risk of failure from loose connections or cracked welds and / or may require additional machining or welding operations to add counterweights that are bolted or welded to lifting hardware. Therefore, bolting or welding on lifting hardware may be less robust (e.g., lower strength), less secure, more prone to failure, and higher cost.

[0048] According to the examples described herein, the lifting eye with the counterweight embedded therein is stronger (e.g., higher strength), safer, less prone to failure, and less expensive than bolting or welding on lifting hardware. Burning the lifting eye to form within the entire profile of the counterweight slab is cost effective. For example, the cost of burning additional profiles corresponding to the embedded lifting eye may be negligible compared to the cost of burning other counterweight slabs.

[0049] According to the examples described herein, the lifting eye with the counterweight embedded therein may be particularly suitable for a counterweight assembly having a center slab (e.g., a counterweight assembly having an odd number of individual slabs, such as 3, 5, or 7 slabs in total). For example, the center of gravity of the entire assembly needs to be positioned directly below the lifting eye (e.g., to help slide the mounting structure of the counterweight assembly onto the machine). For an odd number of slabs only, the current slab thickness may be maintained and the center slab may be replaced with a new center slab having the lifting eye embedded therein.

[0050] The above disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation to the precise form disclosed. Modifications and variations may be made in light of the above disclosure, or may be acquired from the practice of the implementation. In addition, any implementation described herein may be combined, unless the above invention explicitly provides reasons why one or more implementations cannot be combined. Even though specific combinations of features are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various implementations. Although each dependent claim listed below may be directly dependent on only one claim, the disclosure of the various implementations includes each dependent claim in combination with all other claims in the claim set.

[0051] As used herein, "one", "a" and "a group" are intended to include one or more items and can be used interchangeably with "one or more". In addition, as used herein, the article "said" is intended to include one or more items related to the article "said", and can be used interchangeably with "said one or more". In addition, the phrase "based on" is intended to mean "based at least in part on", unless otherwise explicitly stated. In addition, as used herein, the term "or" is intended to be inclusive when used in a series, and can be used interchangeably with "and / or", unless otherwise explicitly stated (for example, if used in combination with "one of" or "only one of"). In addition, for ease of description, spatially relative terms such as "below", "lower", "above", "upper", etc. can be used here to describe the relationship between an element or feature and another element or feature as shown in the figure. In addition to the orientation shown in the figure, spatially relative terms are intended to include different orientations of equipment, devices and / or elements in use or operation. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used here can also be interpreted accordingly.

Claims

1. A counterweight assembly for a crane, comprising: Multiple counterweight slabs, including: first and second external counterweight slabs; and one or more internal counterweight slabs sandwiched between the internal lateral surfaces of the first and second external counterweight slabs, Wherein a center slab of the one or more internal counterweight slabs includes a lifting eye embedded in a body of the center slab.

2. The counterweight assembly of claim 1, wherein the center plate further comprises: outer edge; an inner edge having a step defining an upper portion and a lower portion; a top edge connecting the outer edge and the upper portion; and a bottom edge connecting the outer edge and the lower portion, The lifting eye extends through the top edge.

3. The counterweight assembly of claim 1 , wherein the center plate further comprises: a first lateral surface; a second lateral surface facing away from the first lateral surface; as well as a lateral surface connecting the first lateral surface and the second lateral surface together, Wherein the lifting eye comprises an opening aligned with an axis parallel to the side surface.

4. The counterweight assembly of claim 3, wherein the first lateral surface is a front surface configured to face in a forward direction of the crane, and Wherein the second lateral surface is a rear surface configured to face in an opposite direction of the crane.

5. The counterweight assembly of claim 3, wherein the lifting eye includes a chamfer surrounding the opening, the chamfer configured to prevent wear on a lifting device engaged with the lifting eye.

6. The counterweight assembly of claim 3, wherein a thickness of the lifting eye along the axis is equal to a thickness of the body along the side surface.

7. The counterweight assembly according to claim 1, wherein the plurality of counterweight plate blanks are assembled together into a combined block by bolting or welding.

8. The counterweight assembly of claim 1, wherein the lifting eyes are integral with the body of the center slab without being bolted or welded thereto.

9. The counterweight assembly of claim 1, wherein non-center slabs of the plurality of counterweight slabs are formed of a low-grade steel material, and wherein the center slab is formed of a higher-grade steel material than the non-center slabs.

10. A counterweight slab having a main body for a crane, comprising: a first lateral surface; a second lateral surface facing away from the first lateral surface; a lateral surface connecting the first lateral surface and the second lateral surface together; and A lifting eye embedded in the body, Wherein the lifting eye comprises an opening aligned with an axis parallel to the side surface.

11. The counterweight slab according to claim 10, wherein the body of the counterweight slab further comprises: outer edge; an inner edge having a step defining an upper portion and a lower portion; a top edge connecting the outer edge and the upper portion; and a bottom edge connecting the outer edge and the lower portion, The lifting eye extends through the top edge.

12. The counterweight slab of claim 10, wherein the lifting eye includes a chamfer surrounding the opening, the chamfer configured to prevent wear of a lifting device engaged with the lifting eye.

13. The counterweight slab of claim 10, wherein a thickness of the lifting eye along the axis is equal to a thickness of the body along the side surface.

14. The counterweight slab of claim 10, wherein the lifting eye is integral with the body of the counterweight slab without being bolted or welded to the body.

15. The counterweight slab of claim 10, wherein the first lateral surface is a front surface configured to face in a forward direction of the crane, and Wherein the second lateral surface is a rear surface configured to face in an opposite direction of the crane.

16. A method of manufacturing a counterweight slab for a crane, comprising: Cut the contours of the counterweight slabs from larger steel slabs using a plasma torch, laser or water jet. wherein the contour corresponds to the shape of a first lateral surface of the body of the counterweight slab, and The subject further comprises: a second lateral surface facing away from the first lateral surface; a lateral surface connecting the first lateral surface and the second lateral surface together; and A lifting eye is embedded in the body.

17. The method according to claim 16, further comprising: One or more chamfers are machined into the lifting eye of the counterweight slab.

18. The method of claim 16, wherein the lifting eye is integral with the body of the counterweight slab without being bolted or welded to the body.

19. The method of claim 16, wherein the lifting eye is manufactured together with the main body of the counterweight slab.

20. The method of claim 16, wherein the lifting eye comprises an opening aligned with an axis parallel to the side surface, and Wherein cutting the contour includes forming the opening.

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