Girder deviation adjusting structure and quayside container crane
By adopting a beam tilt adjustment structure in the shore container crane and using the combination of land-side down-pressure wheel support and the tilt adjustment structure, the problem of chewing the rails during the sliding of the beam is solved, and the smooth sliding of the beam and the reliability of the shore container crane are improved.
Patent Information
- Application Number
- CN202420566410.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-22
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-03-22
AI Technical Summary
In shore container cranes, the beams are prone to chewing the rails during the slippage, which affects their smooth operation.
A beam adjusting structure is adopted, which includes a land-side down-pressure wheel support structure and a bias adjusting structure. The land-side down-pressure wheel bearing structure supports the beam through the land-side down-pressure wheel lower support and the upper support, and the bias adjusting structure adjusts the angle between the land-side down-pressure wheel bearing through the rotation of the first connecting plate and the second connecting plate, thereby realizing the bias adjusting of the beam.
By adjusting the position of the beam, avoiding the occurrence of rail gnawing, ensuring smooth operation during the sliding of the beam, and improving the reliability of the shore container crane.
Smart Images
Figure CN222794990U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of cranes, and in particular to a beam deviation adjustment structure and a shore container crane. Background Art
[0002] A shore container crane, also known as a quay crane, is a device used to load and unload containers on container ships at the shore. Therefore, during the operation of the shore container crane, the beam needs to slide between the sea side and the land side.
[0003] At present, with the improvement of the carrying capacity of ships, how to obtain the lifting height under the spreader as much as possible while ensuring that the height of the whole machine is subject to certain restrictions has become a focus of great concern for users of such terminals. It is very important to develop a new generation of low-profile cranes to adapt to new requirements. The new generation of low-profile quay crane suspension system is one of the core systems of the new generation of low-profile cranes. It is a key component to achieve safe and reliable sliding of the beam. Its layout and carrying capacity directly affect the height and sliding reliability of the low-profile crane. However, the problem of gnawing the rails is prone to occur during the sliding process of the beam, which affects the smooth operation of the beam during sliding. Utility Model Content
[0004] The purpose of the utility model is to provide a beam deviation adjustment structure, which can improve the technical problem in the prior art that the beam is prone to gnawing the rail during the sliding process, and ensure the smooth operation of the beam during the sliding process.
[0005] The utility model also aims to provide a shore container crane, which can improve the technical problem in the prior art that the beam is prone to gnawing the rails during the sliding process, and ensure smooth operation of the beam during the sliding process.
[0006] The embodiments of the present invention can be implemented in the following ways:
[0007] A beam deviation adjustment structure, the beam deviation adjustment structure comprising:
[0008] A land side lower pressure wheel support structure, the land side lower pressure wheel support structure comprising a land side lower pressure wheel lower support and a land side lower pressure wheel upper support; the land side lower pressure wheel lower support is used to be installed on the connecting cross beam, and the land side lower pressure wheel upper support is used to support the beam through the land side lower pressure wheel; and
[0009] A deviation adjustment structure, the deviation adjustment structure comprising a first connecting plate and a second connecting plate;
[0010] Among them, the first connecting plate is installed on the lower support of the land-side lower pressure wheel, the second connecting plate is installed on the upper support of the land-side lower pressure wheel, and the first connecting plate and the second connecting plate are rotatably connected to adjust the beam by adjusting the angle between the lower support of the land-side lower pressure wheel and the upper support of the land-side lower pressure wheel.
[0011] Optionally, the first connecting plate is provided with a waist-shaped hole, the second connecting plate is provided with a round hole, and the beam deflection adjustment structure further comprises a locking member, and the locking member cooperates with the waist-shaped hole and the round hole;
[0012] When the locking member is not locked, the first connecting plate and the second connecting plate can rotate relative to each other.
[0013] Optionally, the first connecting plate is provided with a plurality of the waist-shaped holes distributed along the length direction, and the plurality of the waist-shaped holes form a waist-shaped hole row, and the first connecting plate is provided with two waist-shaped hole rows distributed at intervals along the width direction; the second connecting plate is provided with a plurality of the circular holes, and the plurality of the circular holes are arranged one-to-one with the plurality of the waist-shaped holes.
[0014] Optionally, the first waist-shaped hole in the waist-shaped hole row distributed along the length direction is a first waist-shaped hole, the last waist-shaped hole in the waist-shaped hole row distributed along the length direction is a second waist-shaped hole, the line connecting the center of the left semicircle of the first waist-shaped hole and the center of the right semicircle of the second waist-shaped hole is a first line, the length direction extends along the sliding direction of the beam, and the angle between the first line and the length direction is greater than the deflection angle of the beam.
[0015] Optionally, the deviation adjustment structure further includes an elastic pad, and the elastic pad is arranged between the first connecting plate and the second connecting plate.
[0016] Optionally, the first connecting plate and the second connecting plate are connected via a locking piece, and a waist-shaped hole for elastic pad is provided on the elastic pad, and the waist-shaped hole for elastic pad is used for the locking piece to pass through.
[0017] Optionally, the first connecting plate is welded and fixed on the lower support of the land side lower pressure wheel; and / or,
[0018] The second connecting plate is welded and fixed on the upper support of the land side lower pressure wheel.
[0019] A shore container crane comprises the above-mentioned beam deviation adjustment structure.
[0020] The beneficial effects of the beam deviation adjustment structure and the shore container crane provided by the embodiments of the utility model include:
[0021] The embodiment of the utility model provides a beam deviation adjustment structure, which includes a land side lower pressure wheel support structure and a deviation adjustment structure, the land side lower pressure wheel support structure includes a land side lower pressure wheel lower support and a land side lower pressure wheel upper support, the land side lower pressure wheel lower support is used to be installed on the connecting crossbeam, and the land side lower pressure wheel upper support is used to support the beam through the land side lower pressure wheel. The beam deviation adjustment structure includes a first connecting plate and a second connecting plate, the first connecting plate is installed on the land side lower pressure wheel lower support, the second connecting plate is installed on the land side lower pressure wheel upper support, and the first connecting plate and the second connecting plate are rotatably connected, so that when the connecting crossbeam is deformed, causing the beam to deflect, the angle between the land side lower pressure wheel lower support and the land side lower pressure wheel upper support can be adjusted through the relative rotation between the first connecting plate and the second connecting plate, so as to achieve beam deviation adjustment, avoid the technical problem of the beam gnawing the rail, and then help to ensure the smooth operation of the beam during sliding.
[0022] The embodiment of the utility model also provides a shore container crane, which includes the above-mentioned beam deviation adjustment structure. Since the shore container crane includes the above-mentioned beam deviation adjustment structure, it also has the technical problem of achieving beam deviation adjustment and avoiding beam gnawing, thereby helping to ensure the beneficial effect of smooth operation during the beam sliding process. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.
[0024] Figure 1 A schematic diagram of the structure of a central beam of a shore container crane provided according to one aspect of the utility model when in sea testing is shown;
[0025] Figure 2 A schematic diagram of the structure of a shore container crane provided according to one aspect of the utility model when the beam is on the land side is shown;
[0026] Figure 3 A partial structural schematic diagram of a shore container crane provided according to one aspect of the utility model is shown;
[0027] Figure 4 Shows Figure 3 Schematic diagram of the structure from the perspective of middle B;
[0028] Figure 5 Shows Figure 4 Schematic diagram of the structure at DD in the middle;
[0029] Figure 6A structural schematic diagram of a beam deviation adjustment structure provided according to one aspect of the utility model is shown;
[0030] Figure 7 A schematic structural diagram of a first connecting plate in a beam deviation adjustment structure provided according to one aspect of the utility model is shown;
[0031] Figure 8 A schematic structural diagram of a second connecting plate in a beam deviation adjustment structure provided according to one aspect of the utility model is shown;
[0032] Fig. 9 A schematic structural diagram of an elastic pad in a beam deviation adjustment structure provided according to one aspect of the utility model is shown.
[0033] Reference numerals:
[0034] 10-shore container crane; 100-beam adjustment structure; 110-land side lower pressure wheel support structure; 111-land side lower pressure wheel lower support; 112-land side lower pressure wheel upper support; 120-first connecting plate; 121-waist-shaped hole; 122-first waist-shaped hole; 123-second waist-shaped hole; 124-left semicircle center; 125-right semicircle center; 126-first connecting line; 127-length direction; 130-second connecting plate; 131-circular hole; 140-elastic pad; 141-elastic pad waist-shaped hole; 210-beam; 220-connecting beam; 230-suspension system. DETAILED DESCRIPTION
[0035] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention.
[0036] In the description of the present utility model, it should be noted that if the terms "upper", "lower", "inside", "outside", "vertical" and the like appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the utility model product is usually placed when used, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model.
[0037] At the same time, it should be noted that the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.
[0038] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified or limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, an integral connection, or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or the internal communication of two components, etc. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0039] At present, the technical problem of gnawing rails is prone to occur during the sliding process of the beam. The inventor has studied this and found that when the beam is at the sea level and the trolley is at the forward extension position ( Figure 1 At position A1) (as shown below Figure 1 As shown in the figure), the connecting beam of the suspension system bears less load and the corresponding deformation is also small; when the beam is on the land side and the trolley runs to the rear reach position ( Figure 2 At position A2 in the middle) (as shown below Figure 2 The connecting beam is subjected to a large load, which causes deformation, making it easy for the rail to be bitten during the sliding process of the beam.
[0040] The utility model implements the beam deviation adjustment structure and the solution of the shore container crane to solve the above problems.
[0041] Figure 1 FIG. 2 shows a schematic diagram of the structure of the girder 210 of the shore container crane 10 provided in this embodiment when it is in sea testing. Figure 2 FIG. 2 shows a schematic structural diagram of the shore container crane 10 provided in this embodiment when the beam 210 is on the land side. Figure 3 A partial structural diagram of a shore container crane 10 provided in this embodiment, Figure 4 for Figure 3 The structural diagram of the B perspective, Figure 5 for Figure 4 The structural diagram of DD in the figure. Figure 6 This is a structural diagram of the beam deviation adjustment structure 100 provided in this embodiment. Figure 1-Figure 6 This embodiment provides a beam deviation adjustment structure 100 and also provides a shore container crane 10.
[0042] The shore container crane 10 includes a beam adjustment structure 100, and also includes a beam 210, a land side pressure wheel, and a connecting crossbeam 220. The beam adjustment structure 100 is installed on the connecting crossbeam 220, and the beam 210 is supported by the land side pressure wheel installed on the beam adjustment structure 100. Specifically, the shore container crane 10 also includes a suspension system 230, through which the beam 210 is suspended, and the land side pressure wheel can also be regarded as a part of the suspension system 230, and is supported under the beam 210 through the land side pressure wheel. Optionally, the land side pressure wheel can be supported under the lower chord of the beam 210.
[0043] The beam adjustment structure 100 includes a land-side lower pressure wheel support structure 110 and an adjustment structure. The land-side lower pressure wheel support structure 110 includes a land-side lower pressure wheel lower support 111 and a land-side lower pressure wheel upper support 112. The land-side lower pressure wheel lower support 111 is used to be installed on the connecting beam 220, and the land-side lower pressure wheel upper support 112 is used to support the beam 210 through the land-side lower pressure wheel. The beam adjustment structure 100 includes a first connecting plate 120 and a second connecting plate 130. The first connecting plate 120 is installed on the lower support 111 of the land-side lower pressure wheel, and the second connecting plate 130 is installed on the upper support 112 of the land-side lower pressure wheel. The first connecting plate 120 and the second connecting plate 130 are rotatably connected. In this way, when the connecting beam 220 is deformed, causing the beam 210 to deflect, the angle between the lower support 111 of the land-side lower pressure wheel and the upper support 112 of the land-side lower pressure wheel can be adjusted by relative rotation between the first connecting plate 120 and the second connecting plate 130, so as to realize the adjustment of the beam 210 and avoid the technical problem of the beam 210 gnawing the rail, which helps to ensure the smooth operation of the beam 210 during the sliding process.
[0044] The beam deviation adjustment structure 100 provided in this embodiment is further described below:
[0045] Figure 7 FIG. 1 shows a schematic structural diagram of the first connecting plate 120 in the beam deviation adjustment structure 100 provided in this embodiment. Figure 8 This is a schematic diagram of the structure of the second connecting plate 130 in the beam deviation adjustment structure 100 provided in this embodiment. Figure 1-Figure 8In this embodiment, a waist-shaped hole 121 is provided on the first connecting plate 120, and a round hole 131 is provided on the second connecting plate 130. The beam deviation adjustment structure 100 also includes a locking member, which cooperates with the waist-shaped hole 121 and the round hole 131, so that the first connecting plate 120 and the second connecting plate 130 are connected through the locking member. At the same time, since the hole provided on the first connecting plate 120 is a waist-shaped hole 121, the waist-shaped hole 121 provides a certain activity space for the relative movement of the first connecting plate 120 and the second connecting plate 130. When the locking member is not locked, the first connecting plate 120 and the second connecting plate 130 can rotate relative to each other, thereby making the angle between the lower support 111 of the land side lower pressure wheel and the upper support 112 of the land side lower pressure wheel adjustable, and then when the connecting crossbeam 220 is deformed, the extension direction of the beam 210 can be made consistent with the running direction by adjusting the deviation, thereby avoiding the problem of gnawing the rail.
[0046] Optionally, the locking member (not shown) may be a bolt substructure, which includes a locking bolt and a locking nut. The locking bolt passes through the waist-shaped hole 121 and the round hole 131 and is threadedly connected with the locking nut. When the locking nut is tightened and fixed on the locking bolt, the first connecting plate 120 and the second connecting plate 130 are relatively fixed; when the locking nut is not tightened on the locking bolt, the first connecting plate 120 can rotate within a certain range relative to the second connecting plate 130. Optionally, the locking bolt may be of M30×120 type.
[0047] Further, the first connecting plate 120 is provided with a plurality of waist-shaped holes 121 distributed along the length direction 127, and the plurality of waist-shaped holes 121 form a waist-shaped hole 121 column, and the first connecting plate 120 is provided with two waist-shaped hole 121 columns spaced apart along the width direction. The second connecting plate 130 is provided with a plurality of round holes 131, and the plurality of round holes 131 are arranged one-to-one with the plurality of waist-shaped holes 121. In other words, the second connecting plate 130 is provided with two round hole 131 columns spaced apart along the width direction, and each round hole 131 column includes a plurality of round holes 131 extending along the length direction.
[0048] Specifically, the first connecting plate 120 and the second connecting plate 130 are both rectangular plate-shaped members, and the waist-shaped holes 121 are distributed along the length direction 127 of the first connecting plate 120, and the two waist-shaped holes 121 are distributed at intervals along the width direction of the first connecting plate 120. The waist-shaped holes 121 on the first connecting plate 120 include a straight bar segment and two semicircular portions located at both ends of the straight bar segment, and the two semicircular portions are respectively a left semicircular portion and a right semicircular portion, and the left semicircular portion, the straight bar segment and the right semicircular portion are arranged along the width direction of the first connecting plate 120, that is, the waist-shaped holes 121 extend along the width direction of the first connecting plate.
[0049] Further, the first waist-shaped hole 121 in the row of waist-shaped holes 121 distributed along the length direction 127 is the first waist-shaped hole 122, the last waist-shaped hole 121 in the row of waist-shaped holes 121 distributed along the length direction 127 is the second waist-shaped hole 123, the line connecting the left semicircle center 124 of the first waist-shaped hole 122 and the right semicircle center 125 of the second waist-shaped hole 123 is the first connecting line 126, and the angle between the first connecting line 126 and the length direction 127 is greater than the deflection angle of the beam. The length direction 127 extends along the sliding direction of the beam 210, so that the second connecting plate 130 and the first connecting plate 120 can rotate relative to each other by sliding the second connecting plate 130 relative to the waist-shaped hole 121.
[0050] Specifically, the center of the left semicircle of the first waist-shaped hole 122 is the center of the left semicircle 124, and the center of the right semicircle of the second waist-shaped hole 123 is the center of the right semicircle 125. The angle formed by the angle between the first connecting line 126 and the length direction of the first connecting plate 120 is the maximum deflection angle, which can be set according to the maximum deflection angle that may occur in the beam 210 during design. Accordingly, the number of locking members in the beam deflection adjustment structure 100 is adapted to the number of waist-shaped holes 121 and round holes 131.
[0051] In this embodiment, the first connecting plate 120 is welded and fixed on the lower support 111 of the lower pressure wheel on the land side, so that the first connecting plate 120 is fixedly connected to the lower support 111 of the lower pressure wheel on the land side. At the same time, the first connecting plate 120 is arranged horizontally, in other words, the plate surface of the first connecting plate 120 is located in the horizontal plane. Similarly, in this embodiment, the second connecting plate 130 is welded and fixed to the lower end of the upper support 112 of the lower pressure wheel on the land side, so that the second connecting plate 130 is fixedly connected to the upper support 112 of the lower pressure wheel on the land side. At the same time, the second connecting plate 130 is arranged horizontally, in other words, the plate surface of the second connecting plate 130 is located in the horizontal plane.
[0052] It is understandable that in some other embodiments, the first connecting plate 120 can also be fixedly connected to the land-side lower pressure wheel lower support 111 by other means. Similarly, the second connecting plate 130 can also be fixed to the lower end of the land-side lower pressure wheel upper support 112 by other means.
[0053] Fig. 9 This is a schematic diagram of the structure of the elastic pad 140 in the beam adjustment structure 100 provided in this embodiment. Figure 1-Figure 9 In this embodiment, the deflection adjustment structure further includes an elastic pad 140 disposed between the first connecting plate 120 and the second connecting plate 130, and the second connecting plate 130 is elastically supported by the elastic pad 140. Optionally, the elastic pad 140 includes but is not limited to a crane spring pad made by Fabreeka.
[0054] Specifically, the elastic pad 140 is substantially consistent in size and shape with the first connecting plate 120 and the second connecting plate 130 , that is, the elastic pad 140 is a rectangular plate-shaped member.
[0055] Furthermore, the elastic pad 140 is provided with a waist-shaped elastic pad hole 141121, through which the locking member can be inserted into the elastic pad 140 to meet the connection requirements of the locking member to the first connecting plate 120 and the second connecting plate 130. On the other hand, since the through hole provided on the elastic pad 140 for the locking member to be inserted is waist-shaped, the relative position between the elastic pad 140 and the first connecting plate 120 is fixed during the relative rotation of the first connecting plate 120 and the second connecting plate 130. Specifically, the waist-shaped elastic pad hole 141121 on the elastic pad 140 corresponds to the waist-shaped hole 121 on the first connecting plate 120 one by one, and the waist-shaped elastic pad hole 141121 on the elastic pad 140 can be set to be the same size as the waist-shaped hole 121 on the first connecting plate 120.
[0056] The beam deviation adjustment structure 100 and the shore container crane 10 provided by the embodiment of the utility model, when in use, the deviation angle Q of the beam 210 is calculated in advance, and then the waist-shaped hole 121 on the beam deviation adjustment structure 100 is used to adjust the position of the beam 210, so that the length extension direction of the beam 210 is consistent with the sliding direction of the beam 210, that is, both are along the same direction as shown in FIG. Figure 1 and Figure 2 In the left and right directions, the rail gnawing problem that occurs during the sliding of the beam 210 is improved, and the reliability of the sliding of the beam 210 is ensured.
[0057] Accordingly, an embodiment of the utility model further provides a beam adjustment method for a shore container crane, which can be used for the above-mentioned shore container crane 10. Specifically, the beam adjustment method for the shore container crane includes the following steps:
[0058] S01: Calculate the angle Q of the beam deflection.
[0059] S02: Manipulate the second connecting plate to rotate at an angle Q relative to the first connecting plate, so as to deflect the relative angle between the lower support of the land-side lower pressure wheel and the upper support of the land-side lower pressure wheel, thereby realizing the adjustment of the beam.
[0060] Through the waist-shaped hole on the second connecting plate, the relative angle between the second connecting plate and the first connecting plate is rotated by an angle Q (such as Figure 5 As shown), the upper support of the lower pressure wheel on the land side rotates by an angle Q relative to the lower support of the lower pressure wheel on the land side, and the beam deflects in the opposite direction by an angle Q, thereby adjusting the beam back to its original angle to achieve the adjustment of the beam.
[0061] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technology in this field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention.
Claims
1. A beam deviation adjustment structure, characterized in that: The beam deviation adjustment structure comprises: A land side lower pressure wheel support structure, the land side lower pressure wheel support structure comprising a land side lower pressure wheel lower support and a land side lower pressure wheel upper support; the land side lower pressure wheel lower support is used to be installed on the connecting cross beam, and the land side lower pressure wheel upper support is used to support the beam through the land side lower pressure wheel; and A deviation adjustment structure, the deviation adjustment structure comprising a first connecting plate and a second connecting plate; Among them, the first connecting plate is installed on the lower support of the land-side lower pressure wheel, the second connecting plate is installed on the upper support of the land-side lower pressure wheel, and the first connecting plate and the second connecting plate are rotatably connected to adjust the beam by adjusting the angle between the lower support of the land-side lower pressure wheel and the upper support of the land-side lower pressure wheel.
2. The beam deviation adjustment structure according to claim 1, characterized in that: The first connecting plate is provided with a waist-shaped hole, the second connecting plate is provided with a round hole, and the beam deflection adjustment structure further comprises a locking member, and the locking member cooperates with the waist-shaped hole and the round hole; When the locking member is not locked, the first connecting plate and the second connecting plate can rotate relative to each other.
3. The beam deviation adjustment structure according to claim 2, characterized in that: The first connecting plate is provided with a plurality of waist-shaped holes distributed along the length direction, and the plurality of waist-shaped holes form a waist-shaped hole row. The first connecting plate is provided with two waist-shaped hole rows distributed at intervals along the width direction; the second connecting plate is provided with a plurality of round holes, and the plurality of round holes are arranged one-to-one correspondingly with the plurality of waist-shaped holes.
4. The beam deviation adjustment structure according to claim 3, characterized in that: The first waist-shaped hole in the waist-shaped hole row distributed along the length direction is the first waist-shaped hole, the last waist-shaped hole in the waist-shaped hole row distributed along the length direction is the second waist-shaped hole, the line connecting the center of the left semicircle of the first waist-shaped hole and the center of the right semicircle of the second waist-shaped hole is the first line, the length direction extends along the sliding direction of the beam, and the angle between the first line and the length direction is greater than the deflection angle of the beam.
5. The beam deviation adjustment structure according to claim 1, characterized in that: The deflection adjustment structure further includes an elastic pad, and the elastic pad is arranged between the first connecting plate and the second connecting plate.
6. The beam deviation adjustment structure according to claim 5, characterized in that: The first connecting plate and the second connecting plate are connected by a locking piece, and a waist-shaped hole for elastic pad is provided on the elastic pad, and the waist-shaped hole for elastic pad is used for the locking piece to pass through.
7. The beam deviation adjustment structure according to claim 1, characterized in that: The first connecting plate is welded and fixed on the lower support of the lower pressure wheel on the land side; and / or, The second connecting plate is welded and fixed on the upper support of the land side lower pressure wheel.
8. A shore container crane, characterized in that: The shore container crane comprises the beam adjustment structure as described in any one of claims 1-7.