Vibrating equipment for building construction
By designing a flexible vibration isolation pad and a rigid connection auxiliary control device on the vibrator, the problems of hand fatigue and uneven vibration of existing vibrators have been solved, achieving stable operation and efficient construction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 杨旭
- Filing Date
- 2025-06-23
- Publication Date
- 2026-04-28
AI Technical Summary
Existing vibrators suffer from problems such as hand fatigue, uneven compaction, and cumbersome operation, which affect construction efficiency and concrete quality.
An auxiliary control device was designed, comprising a flexible vibration isolation pad, a clamping kit, an operating rod, and a positioning clamp. Through rigid connection and flexible isolation, it enables precise control of the vibrating rod and reduces vibration transmission.
It improves the uniformity of vibration, reduces operator fatigue, and enhances construction efficiency and concrete quality.
Smart Images

Figure CN224173740U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of building construction equipment, and in particular to a vibratory compaction device used in building construction. Background Technology
[0002] In the construction process, concrete vibration is a crucial step in ensuring concrete quality. As the primary equipment for achieving concrete compaction, the performance and ease of operation of the vibrator directly affect construction efficiency and the quality of the formed concrete. For example... Figure 1 As shown, existing vibrators generally consist of a motor, a flexible shaft, and a vibrating rod. The rotational torque generated by the motor is transmitted to the vibrating rod through the flexible shaft, driving the planetary gears to rotate at high speed, thereby generating powerful vibrational energy that expels air bubbles from the concrete, achieving a compaction effect.
[0003] However, in practice, existing vibrators have revealed many problems:
[0004] On the one hand, while transmitting torque, flexible shafts also transmit a large amount of vibration energy to the operator's hands. Prolonged continuous operation can easily lead to fatigue, numbness, and other discomfort in the operator's hands, and in severe cases, may even cause occupational diseases such as vibration sickness, posing a significant threat to the operator's health.
[0005] On the other hand, due to the inherent flexibility of the flexible shaft, it is difficult for operators to precisely control the insertion angle and depth of the vibrator when inserting it into the concrete. An improper insertion angle may lead to uneven compaction of the concrete, resulting in localized air bubbles or over-vibration; an inaccurate insertion depth may prevent effective compaction of the underlying concrete layers or result in over-vibration, affecting the overall quality of the concrete.
[0006] In addition, existing vibrators lack specially designed devices to facilitate user gripping of the flexible shaft. Operators need to constantly adjust the position of the flexible shaft during operation, which is cumbersome and inconvenient and reduces construction efficiency.
[0007] In view of this, the inventor has specifically designed a vibratory compaction device for building construction, and this invention arises from this. Utility Model Content
[0008] To solve the above problems, the technical solution of this utility model is as follows:
[0009] A vibratory compaction device for building construction includes a motor, a flexible shaft, and a vibratory rod, and also includes an auxiliary control device. The auxiliary control device includes a flexible vibration isolation pad sleeved on the connection position between the flexible shaft and the vibratory rod, a clamping assembly detachably clamped to the end of the vibratory rod, an operating rod, and a positioning clamp. The clamping assembly is composed of two clamping units joined together. The two clamping units are provided with a plug-in base on their opposite sides. The operating rod is detachably connected to the plug-in base and distributed parallel to the vibratory rod. The positioning clamp includes positioning units respectively provided on the two operating rods. The two positioning units are magnetically engaged and, when joined together, form a clamping groove that fits into the outer periphery of the flexible shaft. The flexible vibration isolation pad is disposed between the clamping assembly and the vibratory rod and within the clamping groove.
[0010] Preferably, the jacket unit has a semi-circular structure, and the two jacket units are spliced together to form an installation groove that is adapted to the end of the vibrator. The two connection positions of the two jacket units form a connecting edge that contacts each other, and the two adjacent connecting edges are locked and fixed by connecting bolts.
[0011] Preferably, the two jacket units protrude from opposite sides to form a one-piece hinge seat. The insertion base is sleeve-shaped, with an insertion groove at one end for insertion into the end of the operating rod, and the other end extending to form two hinge pieces that are hinged to the hinge seat. The hinge pieces and the hinge seat are fixed to each other by a damping shaft.
[0012] Preferably, a quick-release structure is provided between the insertion slot and the end of the operating rod.
[0013] Preferably, the quick-release structure includes positioning bolts symmetrically inserted through the inner walls on both sides of the insertion slot, a limiting block at the end of the positioning bolt, a limiting spring for driving the limiting block to move toward the inside of the insertion slot, an annular limiting groove formed by recessing inward along the bottom side wall of the operating rod, and a limiting unlocking ring slidably sleeved in the annular limiting groove. The limiting block has an inclined first guide surface, and the first guide surface extends inclined toward the center of the bottom of the insertion slot along the side close to the opening of the insertion slot. The end of the operating rod forms an arc-shaped guide edge. The limiting unlocking ring includes two symmetrically arranged second guide surfaces and a third guide surface, which are joined together to form a pointed structure protruding outward.
[0014] Preferably, the operating rod is slidably provided with a locking rod and a locking spring for driving the locking rod to move toward the bottom of the insertion groove. When the limiting block is engaged with the annular limiting groove, the end of the locking rod movably contacts the bottom of the insertion groove. The other end of the locking rod is provided with an operating structure integrally connected to the locking rod and used to pull the locking rod.
[0015] Preferably, the end of the operating rod is provided with a gripping part, and the operating structure is a cap that is movably sleeved on the end of the gripping part.
[0016] Preferably, the operating structure includes a connecting seat located at the end of the operating rod and connected to the locking rod, a connecting rib fixed to the connecting seat on the side facing the flexible shaft, and a gripping sleeve fixed to the connecting rib. The two gripping sleeves are joined together to form a sleeve structure that can be fitted onto the outside of the softening shaft.
[0017] Preferably, the flexible vibration isolation pad is a silicone vibration isolation pad.
[0018] Preferably, a plurality of perforated grooves are formed through the flexible vibration isolation pad, and the plurality of perforated grooves make the surface of the flexible vibration isolation pad form a mesh structure.
[0019] The beneficial effects of this utility model are as follows:
[0020] First, the clamping kit forms a rigid connection with the operating rod, and with the positioning clamp, it is easy to accurately adjust the insertion angle and depth of the vibrator, thereby improving the uniformity of vibration.
[0021] Secondly, flexible vibration isolation pads block the transmission of vibration to the hands, reducing operator fatigue and lowering the risk of occupational diseases.
[0022] In addition, the flexible vibration isolation pad is made of silicone with a mesh-like perforated groove on the surface to enhance the vibration isolation effect.
[0023] In addition, the quick-release structure and magnetic positioning design enable rapid assembly, and the grip is ergonomic, improving construction efficiency.
[0024] In summary, this utility model, through the clamping kit, operating rod, positioning clamp, and flexible vibration isolation pad, forms an auxiliary control device that is rigidly connected as a whole to the vibrator and the flexible shaft. On the one hand, it can enhance the operation effect of the vibrator, facilitate the operation and adjustment of the insertion angle of the vibrator, and on the other hand, it can also avoid injury to the hands. Ultimately, it can achieve stable control of the vibrator, improve construction efficiency, and fully maintain the overall quality of concrete vibration. Attached Figure Description
[0025] The accompanying drawings, which are provided to further illustrate the present invention and constitute a part of the present invention, illustrate exemplary embodiments of the present invention and are used to explain the present invention, but do not constitute an undue limitation of the present invention.
[0026] in:
[0027] Figure 1 This is a schematic diagram of the overall structure of existing technology;
[0028] Figure 2 This is a schematic diagram of the overall structure of Embodiment 1 of this utility model;
[0029] Figure 3This is a partial structural schematic diagram of the auxiliary control device in Embodiment 1 of this utility model;
[0030] Figure 4 This is a partial exploded structural diagram of Embodiment 1 of this utility model;
[0031] Figure 5 This is a partial exploded view of the clamping kit installation structure in Embodiment 1 of this utility model;
[0032] Figure 6 This is a partial cross-sectional view of the quick-release structure in Embodiment 1 of this utility model;
[0033] Figure 7 This is a schematic diagram of the overall structure of Embodiment 2 of this utility model.
[0034] Label Explanation:
[0035] 100. Motor; 200. Flexible shaft; 300. Vibrator; 400. Auxiliary control device; 500. Flexible vibration isolation pad; 510. Hollowed-out groove; 600. Clamping kit; 610. Clamping unit; 620. Plug-in base; 621. Plug-in slot; 622. Hinge plate; 623. Damping shaft; 624. Limiting hole; 630. Mounting slot; 640. Connecting edge; 650. Connecting bolt; 660. Hinge seat; 700. Operating rod; 710. Arc-shaped guide edge; 720. Locking rod; 721. Push edge; 730 740. Locking spring; 741. Operating structure; 742. Grip part; 743. Cover; 744. Sliding space; 745. Through hole; 746. Connecting seat; 747. Connecting rib; 748. Grip sleeve; 750. Sliding hole; 800. Positioning clip; 810. Positioning unit; 900. Quick release structure; 910. Positioning bolt; 920. Limiting block; 921. First guide surface; 930. Limiting spring; 940. Annular limiting groove; 950. Limiting unlocking ring; 951. Second guide surface; 952. Third guide surface. Detailed Implementation
[0036] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model. Example
[0037] Please see Figures 2 to 6 This is a preferred embodiment of the present invention, which is a vibrating device for building construction, including a motor 100, a flexible shaft 200 and a vibrating rod 300.
[0038] Specifically, the working principle of the vibratory compaction equipment is as follows: the rotational torque generated by the motor 100 is transmitted to the vibratory rod 300 through the flexible shaft 200, which drives the planetary gear inside the vibratory rod 300 to rotate at high speed, thereby generating strong vibration energy, causing the air bubbles inside the concrete to be expelled, and achieving a compaction effect. This is existing technology and will not be elaborated here.
[0039] like Figure 2 , 3 As shown, it also includes an auxiliary control device 400, which includes a flexible vibration isolation pad 500 sleeved on the connection position between the flexible shaft 200 and the vibrating rod 300, a clamping kit 600 detachably clamped to the end of the vibrating rod 300, an operating rod 700, and a positioning clamp 800. The clamping kit 600 is composed of two clamping units 610 assembled together. The side of the two clamping units 610 that is far apart from each other is provided with a plug-in base 620. The operating rod 700 is detachably connected to the plug-in base 620 and distributed parallel to the vibrating rod 300. The positioning clamp 800 includes positioning units 810 respectively provided on the two operating rods 700. The two positioning units 810 are magnetically attracted to each other and form a clamping groove that fits into the outer periphery of the flexible shaft 200 when assembled. The flexible vibration isolation pad 500 is disposed between the clamping kit 600 and the vibrating rod 300 and in the clamping groove.
[0040] Specifically, the sleeve groove is circular (not shown in the figure), which fits perfectly with the overall shape of the outer periphery of the flexible shaft 200. After the flexible vibration damping pad 500 is inserted into the sleeve groove, the positioning sleeve 800 is tightly clamped on the outer periphery of the flexible shaft 200. In addition, strong magnet pieces (not shown in the figure), such as neodymium magnet pieces, are fixedly installed at the two connection positions on both sides of the two positioning sleeves 800, so that the two positioning units 810 can be stably spliced together and can be easily separated under the action of a certain external force, which facilitates the connection and fixation between the operating rod 700 and the flexible shaft 200.
[0041] Preferred, such as Figure 4 , 5 As shown, the jacket unit 610 has a semi-circular structure. The two jacket units 610 are spliced together to form an installation groove 630 that is adapted to the end of the vibrator 300. The two connection positions of the two jacket units 610 form a connecting edge 640 that contacts each other. The two adjacent connecting edges 640 are locked and fixed by connecting bolts 650 and corresponding nuts, washers and other structures.
[0042] Thus, by locking the connecting bolts 650, the two jacket units 610 can be easily fixed and disassembled, which facilitates the formation of a fixed foundation on the vibrator 300 and makes disassembly, maintenance, and storage convenient.
[0043] Preferred, such as Figure 5 , 6As shown, a one-piece hinge seat 660 protrudes from one side of the two jacket units 610 that are far apart from each other. The insertion base 620 is sleeve-shaped, with an insertion groove 621 at one end that is inserted and engaged with the end of the operating rod 700, and the other end extends to form two hinge pieces 622 that are hinged and engaged with the hinge seat 660. The hinge pieces 622 and the hinge seat 660 are rotatably fixed together by a damping shaft 623.
[0044] Thus, the damped rotational connection between the hinge seat 660 and the plug-in base 620 is achieved through the damping shaft 623, which allows for arbitrary positioning of the orientation of the plug-in slot 621. This facilitates user control of the direction of the operating rod 700, enabling it to be parallel to the vibrating rod 300 and the flexible shaft 200 for easy insertion, or to be at a certain angle to the vibrating rod 300 and the flexible shaft 200, which is convenient for special vibration scenarios such as concrete vibration in confined spaces, making the vibration equipment more flexible and versatile.
[0045] Preferred, such as Figure 6 As shown, a quick-release structure 900 is provided between the insertion slot 621 and the end of the operating rod 700.
[0046] In this embodiment, the quick-release structure 900 includes positioning bolts 910 symmetrically inserted through the inner walls of both sides of the insertion groove 621, a limiting block 920 disposed at the end of the positioning bolt 910, a limiting spring 930 that drives the limiting block 920 to move toward the inside of the insertion groove 621, an annular limiting groove 940 formed by recessing inward along the bottom side wall of the operating rod 700, and a limiting unlocking ring 950 slidably sleeved in the annular limiting groove 940. The limiting block 920 has an inclined first guide surface 921, and the first guide surface 921 extends inclined toward the center of the bottom of the insertion groove 621 along the side close to the opening of the insertion groove 621. In this embodiment, the first guide surface 921 is inclined toward the center of the bottom of the insertion groove 621. The end of the operating rod 700 forms an arc-shaped guide edge 710. The limiting unlocking ring 950 includes two symmetrically arranged second guide surfaces 951 and third guide surfaces 952. The second guide surfaces 951 and third guide surfaces 952 are joined together to form a pointed structure protruding outward.
[0047] Thus, under normal conditions, when the end of the operating rod 700 is inserted into the insertion slot 621, the first guide surface 921 of the limiting block 920 first contacts the arc-shaped guide edge 710, compressing the positioning bolt 910 to retract and make room. When the end of the operating rod 700 continues to be inserted, the limiting block 920 loses its limiting position and is pushed into the annular limiting groove 940 under the action of the limiting spring 930, forming a limiting stop with the end face of the structure where the arc-shaped guide edge 710 is located, preventing the operating rod 700 from passing through the insertion slot 621.
[0048] Conversely, to remove the operating rod 700, simply continue pushing the operating rod 700 inward, so that the first guide surface 921 of the limiting block 920 first contacts the second guide surface 951, and under its guidance, smoothly crosses the second guide surface 951 to a position below the third guide surface 952. At this time, the entire limiting unlocking ring 950 is lifted to a position above the limiting block 920. Then, pull the operating rod 700 outward. During the pulling process, the limiting unlocking ring 950 is driven to move to the top of the annular limiting groove 940. Then, under the guidance of the third guide surface 952, the positioning bolt 910 continues to compress and move to a position outside the annular limiting groove 940. When the limiting block 920 moves to a position away from the third guide surface 952, the operating rod 700 can be smoothly pulled out from the insertion slot 621, completing the installation, fixing and disassembly process of the operating rod 700.
[0049] In this embodiment, the insertion base 620 is located on the inner side wall of the insertion groove 621, forming a limiting hole 624 for the limiting block 920 to pass through. The limiting spring 930 is installed on the outside of the rod of the positioning bolt 910 and is located between the bottom of the limiting hole 624 and the end face of the limiting block 920, thereby forming an elastic support force based on the bottom of the limiting hole 624 and toward the end face of the limiting block 920, so that the limiting block 920 has a tendency to move toward the inside of the insertion groove 621.
[0050] Furthermore, in order to improve the stability of the operating rod 700 in the insertion slot 621, a locking rod 720 and a locking spring 730 for driving the locking rod 720 to move toward the bottom of the insertion slot 621 are slidably provided in the operating rod 700. When the limiting block 920 is in limiting cooperation with the annular limiting groove 940, the end of the locking rod 720 is in contact with the bottom of the insertion slot 621. The other end of the locking rod 720 is provided with an operating structure 740 integrally connected to the locking rod 720 and used to pull the locking rod 720.
[0051] In this embodiment, the end of the operating rod 700 is provided with a gripping part 741, and the operating structure 740 is a cover 742 movably sleeved on the end of the gripping part 741. A sliding hole 750 for the locking rod 720 to slide is formed through the interior of the operating rod 700. The gripping part 741 is cylindrical and has a hollow sliding space 743 inside. The end of the sliding space 743 has a through hole 744 for the locking rod 720 to pass through. The locking rod 720 is located in the sliding space 743 and a push edge 721 is fixed thereon. The aforementioned locking spring 730 is sleeved between the push edge 721 and the inner wall of the through hole 744, so that the locking rod 720 can be locked through the through hole 744. Based on the wall, an elastic thrust is formed on the pushing edge 721, causing the entire locking rod 720 to tend to move towards the bottom of the insertion slot 621. Under normal conditions, the end of the locking rod 720 is in active contact with the bottom of the insertion slot 621. At this time, under the limitation of the locking rod 720, the operating rod 700 cannot be pushed inward, so it cannot be taken out from the insertion slot 621. When it is necessary to take out the operating rod 700, simply pull the operating structure 740 outward to drive the locking rod 720 inward, leaving a distance for the operating rod 700 to continue to push inward. At this time, the operating rod 700 can be pushed inward to facilitate the removal of the operating rod 700.
[0052] Preferably, the flexible vibration isolation pad 500 is a silicone vibration isolation pad.
[0053] Preferably, a plurality of perforated grooves 510 are formed through the flexible vibration isolation pad 500, and the plurality of perforated grooves 510 make the surface of the flexible vibration isolation pad 500 form a mesh structure.
[0054] In particular, in actual use, the depth to which the vibrator 300 is inserted into the concrete generally does not exceed 3 / 4 of the vibrator 300. Therefore, fixing the auxiliary control device 400 to the end of the vibrator 300 will prevent the auxiliary control device 400 from being submerged in the concrete during operation, thereby maintaining stable operation of the vibrator 300. Example
[0055] Please see Figure 7 This is a vibration device for building construction, which is an embodiment 2 of the present invention. The difference from embodiment 1 is that the operating structure 740 includes a connecting seat 745 located at the end of the operating rod 700 and connected to the locking rod 720, a connecting rib 746 fixed to the side of the connecting seat 745 facing the flexible shaft 200, and a gripping sleeve 747 fixed to the connecting rib 746. The two gripping sleeves 747 are assembled to form a sleeve structure that can be sleeved on the outside of the softening shaft (not shown in the figure).
[0056] Thus, through the two grip sleeves 747, an integral sleeve structure can be formed on the outside of the flexible shaft 200, which further facilitates the operator to directly control the flexible shaft 200 and the vibrator 300.
[0057] The beneficial effects of this utility model are as follows:
[0058] This invention establishes a rigid connection between the clamping kit 600 and the end of the vibrator 300. A rigid operating rod 700, detachably connected to the clamping kit 600, forms the basis for the operator's grip. A positioning sleeve 800, along with a secondary limit on the flexible shaft 200, creates an auxiliary control device 400 with a rigid overall connection. This enhances the operation of the vibrator 300, facilitates operation and adjustment of the insertion angle, and, with the flexible vibration isolation pad 500, isolates vibration to prevent hand injury. Ultimately, it achieves stable control of the vibrator 300, is easy to operate, has high construction efficiency, and fully maintains the overall quality of concrete compaction.
[0059] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.
Claims
1. A vibratory compaction device for building construction, comprising a motor (100), a flexible shaft (200), and a vibratory rod (300), characterized in that, It also includes an auxiliary control device (400), which includes a flexible vibration isolation pad (500) sleeved on the connection position of the flexible shaft (200) and the vibrating rod (300), a clamping kit (600) detachably clamped to the end of the vibrating rod (300), an operating rod (700), and a positioning clamp (800). The clamping kit (600) is composed of two clamping units (610) assembled together, and a plug-in base is provided on the side of the two clamping units (610) that are far apart from each other. 620), the operating rod (700) is detachably connected to the plug-in base (620) and distributed parallel to the vibrating rod (300). The positioning sleeve (800) includes positioning units (810) respectively provided on the two operating rods (700). The two positioning units (810) are magnetically engaged and form a sleeve groove that fits into the outer periphery of the flexible shaft (200) when they are spliced. The flexible vibration isolation pad (500) is disposed between the sleeve assembly (600) and the vibrating rod (300) and in the sleeve groove.
2. The vibratory compaction equipment for building construction according to claim 1, characterized in that, The jacket unit (610) has a semi-circular structure. The two jacket units (610) are spliced together to form an installation groove (630) that is adapted to the end of the vibrator (300). The two connection positions of the two jacket units (610) form a connecting edge (640) that contacts each other. The two adjacent connecting edges (640) are locked and fixed together by connecting bolts (650).
3. A vibratory compaction device for building construction according to claim 2, characterized in that, The two jacket units (610) protrude from opposite sides to form a one-piece hinge seat (660). The plug-in base (620) is sleeve-shaped, with a plug groove (621) at one end for plugging into the end of the operating rod (700), and the other end extends to form two hinge pieces (622) that are hinged to the hinge seat (660). The hinge pieces (622) and the hinge seat (660) are rotatably fixed together by a damping shaft (623).
4. A vibratory compaction device for building construction according to claim 3, characterized in that, A quick-release structure (900) is provided between the insertion slot (621) and the end of the operating rod (700).
5. A vibratory compaction device for building construction according to claim 4, characterized in that, The quick-release structure (900) includes positioning bolts (910) symmetrically inserted through the inner walls of both sides of the insertion groove (621), a limiting block (920) located at the end of the positioning bolts (910), a limiting spring (930) driving the limiting block (920) to move toward the inside of the insertion groove (621), an annular limiting groove (940) recessed inward along the bottom side wall of the operating rod (700), and a limiting unlocking ring (950) slidably sleeved in the annular limiting groove (940). The limiting block (920) has... There is an inclined first guide surface (921) and the first guide surface (921) extends inclined toward the center of the bottom of the insertion groove (621) along the side close to the opening of the insertion groove (621). The end of the operating rod (700) forms an arc-shaped guide edge (710). The limiting unlocking ring (950) includes two symmetrically arranged second guide surfaces (951) and third guide surfaces (952). The second guide surfaces (951) and third guide surfaces (952) are joined together to form a pointed structure protruding outward.
6. A vibratory compaction device for building construction according to claim 5, characterized in that, The operating rod (700) is slidably provided with a locking rod (720) and a locking spring (730) for driving the locking rod (720) to move toward the bottom of the insertion groove (621). When the limiting block (920) is in limiting cooperation with the annular limiting groove (940), the end of the locking rod (720) is in active contact with the bottom of the insertion groove (621). The other end of the locking rod (720) is provided with an operating structure (740) integrally connected to the locking rod (720) and used to pull the locking rod (720).
7. A vibratory compaction device for building construction according to claim 6, characterized in that, The end of the operating rod (700) is provided with a grip (741), and the operating structure (740) is a cover (742) that is movably sleeved on the end of the grip (741).
8. A vibratory compaction device for building construction according to claim 6, characterized in that, The operating structure (740) includes a connecting seat (745) located at the end of the operating rod (700) and connected to the locking rod (720), a connecting rib (746) fixed to the side of the connecting seat (745) facing the flexible shaft (200), and a grip sleeve (747) fixed to the connecting rib (746). The two grip sleeves (747) are joined together to form a sleeve structure that can be sleeved on the outside of the softening shaft.
9. A vibratory compaction device for building construction according to claim 1, characterized in that, The flexible vibration isolation pad (500) is a silicone vibration isolation pad.
10. A vibratory compaction device for building construction according to claim 9, characterized in that, The flexible vibration isolation pad (500) has several hollowed-out grooves (510) formed through it, and the hollowed-out grooves (510) make the surface of the flexible vibration isolation pad (500) form a mesh structure.