Single-sided bolt fastening assembly

Abstract

The utility model discloses a single edge bolt fastening assembly, including bolt and with the nut of matching, the side of the bolt head of bolt is fixed with fixed head to the screw rod, and the fixed head is the special prism of more than the polygonal mounting hole side surface of the side surface of waiting for connecting spare, and the projection of fixed head in bolt axis direction is located in the outline range of bolt head, and the bolt head can pass through the mounting hole and rotate and retreat to make the fixed head partial side surface and the all side surface of mounting hole and then adhere to the interface to restrict bolt rotation and radial movement, and the bolt head is limited to the outside of mounting hole, and the device can prevent bolt rotation and radial movement in the process of tightening and simple structure and convenient to use.

Description

Technical Field

[0001] This utility model relates to building engineering, and in particular to a single-sided bolt fastening assembly. Background Technology

[0002] In the field of traditional mechanical connections, double-sided operating bolts, requiring space on both sides for installation and fastening, have long constrained their application in engineering projects involving enclosed structures, hollow components, and confined spaces. Such structures often lack pre-designed operating channels, forcing designers to employ alternative solutions such as additional holes, welding, or riveting, resulting in compromised structural integrity, increased manufacturing complexity, and higher maintenance costs. Particularly in aerospace, bridge engineering, and large equipment manufacturing, the demands for lightweight design and high reliability place even greater emphasis on fastening technology, highlighting the limitations of traditional bolts.

[0003] To address the above issues, single-sided bolt technology has emerged. Its core innovation lies in achieving single-sided assembly through asymmetrical threads and a self-locking mechanism at the tail. A typical structure includes a guide thread section, an expansion sleeve, and a torque transmission unit. During installation, only one side needs to be tightened. The sleeve undergoes radial deformation due to axial compression, forming an interference fit with the bore wall of the base material, thus achieving high preload mechanical locking. Compared to traditional solutions, this technology eliminates the limitations of double-sided operation, reduces reliance on auxiliary tooling, and significantly improves fatigue strength. Currently, this technology has been extended to include blind-hole types and shape memory alloy self-locking types, becoming a key basic component in the field of high-end equipment manufacturing.

[0004] Chinese utility model patent CN218440140U discloses a single-sided fastening bolt assembly, comprising: a screw and a nut, and a limiting block sleeved on the screw; wherein the tail of the screw is triangular or quadrilateral; the limiting block is a triangular or quadrilateral prism structure, the size of which is the same as the triangular or quadrilateral tail of the screw; a screw hole for the screw to pass through is provided in the center of the limiting block; the screw passes through a connecting through hole of a component, the connecting through hole being triangular or quadrilateral; the limiting block is sleeved on the outside of the screw inside the connecting through hole of the component, the outer side of the limiting block being engaged in the triangular or quadrilateral connecting through hole of the component, and locked by the nut. This utility model can be installed on one side and fastened to two components with flat plates, achieving the connection performance of ordinary high-strength bolts.

[0005] Although the aforementioned single-sided bolt assembly can achieve a single-sided fixed connection, among the various disclosed structures, only the limiting clip installed on the bolt has a limiting groove corresponding to the tail of the bolt, which can prevent the bolt from rotating and radially rotating during tightening. The other structures cannot prevent the bolt from rotating during tightening. However, such structures are complex, and a limiting component must be installed before using the single-sided bolt. The limiting component has a complex structure and high processing cost. Summary of the Invention

[0006] Purpose of the utility model: The purpose of this utility model is to provide a single-sided bolt fastening assembly that can prevent bolt rotation and radial movement during tightening, and is simple in structure and easy to use.

[0007] Technical solution: The single-sided bolt fastening assembly of this utility model includes a bolt and a matching nut. A fixing head is fixed on the side of the bolt head facing the bolt. The fixing head is an irregular prism with a side surface longer than the side surface of the polygonal mounting hole on the part to be connected. The projection of the fixing head in the bolt axis direction is within the outline range of the bolt head. The bolt head can pass through the mounting hole and rotate and then retract so that the side surface of the fixing head fits against all the sides of the mounting hole to restrict the rotation and radial movement of the bolt. At the same time, the bolt head is limited to the outside of the mounting hole.

[0008] By directly fixing a retaining head inside the bolt head, there is no need to temporarily install a limiting component during use, and the retaining head also eliminates the need for a limiting groove for the bolt head, making the overall structure simpler and easier to use. Because the projection of the retaining head along the bolt axis is within the contour range of the bolt head, the bolt head can pass through the mounting hole, and the retaining head can also pass through the mounting hole. After rotating a certain angle, part of the side of the retaining head can fit against all the sides of the mounting hole. In this way, the bolt can be limited in the mounting hole by the retaining head, preventing both radial movement and rotation. This simplifies the construction and use of single-sided bolts and ensures their stability during tightening.

[0009] Preferably, the number of sides of the cross-section of the fixing head is at least twice the number of sides of the mounting holes.

[0010] This design ensures that the fixing head has enough sides to fit against the mounting hole, while also keeping its axial projection within the outline of the bolt head.

[0011] Preferably, the width of the side of the fixing head that mates with the mounting hole is smaller than the width of the other sides.

[0012] Based on the above settings, the side of the fixing head that fits with the mounting hole can be separated from the side of the bolt head, while the axial projection of the fixing head can be located within the bolt head contour range.

[0013] Beneficial effects: By fixing the fixed head on the side of the bolt head facing the screw, there is no need to install a limiting component during use, and there is no need to set a corresponding limiting groove for the bolt head on the fixed head. This simplifies the overall structure of the single-sided bolt and makes it more convenient to use. At the same time, the fixed head can fit with all sides of the mounting hole after rotating through the mounting hole, which also limits the bolt and prevents it from rotating and moving radially. Attached Figure Description

[0014] Figure 1This is a structural diagram of the component and some of the parts to be connected. Figure 1 ;

[0015] Figure 2 This is a structural diagram of the component and some of the parts to be connected. Figure 2 ;

[0016] Figure 3 This is a structural diagram of the component and some of the parts to be connected. Figure 3 ;

[0017] Figure 4 This is a structural diagram of the component and some of the parts to be connected. Figure 4 ;

[0018] Figure 5 This is a schematic diagram of a bolt structure;

[0019] Figure 6 This is a schematic diagram of the axial projection of the fixing head within the bolt head when the bolt head and the fixing head are respectively an equilateral triangle and a regular hexagon;

[0020] Figure 7 This is a schematic diagram of the axial projection of the fixing head within the bolt head when the bolt head and the fixing head are respectively an equilateral triangle and a hexagon;

[0021] Figure 8 This is a schematic diagram of the axial projection of the fixing head within the bolt head when the bolt head and the fixing head are triangular and hexagonal, respectively.

[0022] Figure 9 This is a schematic diagram showing the axial projection of the fixing head within the bolt head when the bolt head and the fixing head are rectangular and octagonal, respectively.

[0023] The markings in the diagram are as follows: 1. Bolt, 2. Nut, 3. Bolt head, 4. Fixing head, 5. Mounting hole, 6. Washer. Detailed Implementation

[0024] As shown in the figure, the single-sided bolt fastening assembly of this utility model includes a bolt 1 and a matching nut 2. A fixing head 4 is fixed on the side of the bolt head 3 facing the bolt. The fixing head 4 is an irregular prism with more sides than the sides of the polygonal mounting hole 5 on the part to be connected. The projection of the fixing head 4 in the axial direction of the bolt 1 is within the outline of the bolt head 3. The bolt head 3 can pass through the mounting hole 5 and rotate and retract so that part of the side of the fixing head 4 fits against all the sides of the mounting hole 5 to restrict the rotation and radial movement of the bolt 1. At the same time, the bolt head 3 is limited to the outside of the mounting hole 5.

[0025] The component to be connected has a polygonal mounting hole 5. The bolt head 3 can pass through the mounting hole 5. Therefore, the cross-sections of the bolt head 3 and the mounting hole 5 should be set to the same shape. The projection of the fixing head 4 in the axial direction of the bolt 1 is within the outline range of the bolt head 3. Therefore, the bolt head 3 can pass through the mounting hole 5, and the fixing head 4 can also pass through the mounting hole 5.

[0026] The fixing head 4 is an irregularly shaped prism with more sides than the polygonal mounting holes 5 on the parts to be connected. The number of sides of the fixing head 4 depends on the number of sides of the mounting holes 5. For example, if the cross-section of the mounting hole 5 is N-sided, then the cross-section of the fixing head 4 must be at least 2N-sided. This is because when the fixing head 4 passes through the mounting hole 5, rotates, and then retracts into the mounting hole 5, some of its sides must be able to fit against all the sides of the mounting hole 5. This is necessary to limit the bolt 1, preventing it from rotating or moving radially within the mounting hole 5. Therefore, the fixing head 4 must have at least N sides. However, these N sides cannot be directly connected. If they were directly connected into an N-sided shape, then to ensure that the fixing head 4... The axial projection of bolt 1 is located inside the contour of bolt head 3. In order for the side of fixing head 4 to fit with the side of mounting hole 5, each side of fixing head 4 must fit with the side of bolt head 3. That is, fixing head 4 becomes an axial extension of bolt head 3. Although rotating bolt head 3 after passing through mounting hole 5 can limit it outside mounting hole 5, fixing head 4 cannot enter mounting hole 5 to achieve a positioning effect. Therefore, the N sides of fixing head 4 that fit with mounting hole 5 need to be spaced out. That is, a connecting surface needs to be added between adjacent sides. In this way, there are a total of 2N sides, and the cross-section of fixing head 4 is at least a 2N-sided polygon.

[0027] In actual design, the design can be based on the projection of the fixing head 4 into the bolt head 3. For example, first set N interval edges that fit the sides of the bolt head 3 (for distinction, these edges are called fitting edges). Although these fitting edges fit the sides of the bolt head 3, since the bolt head 3 and the mounting hole 5 have the same cross-sectional shape, they actually fit the sides of the mounting hole 5. Then connect these fitting edges in sequence to form a 2N-sided polygon. Then rotate it around the centroid of the bolt head 3 by a certain angle θ so that the polygon projected by the fixing head 4 is located within the outline edge of the bolt head 3. At the same time, the fitting edges are separated from the sides of the bolt head 3. Note that the bolt head 3 cannot re-enter the mounting hole 5 after rotating by θ. Thus, when the bolt head 3 and the fixing head 4 pass through the mounting hole 5, they need to rotate by θ and then retreat to make the fitting edges fit the sides of the mounting hole 5. At the same time, because the bolt head 3 has rotated by θ, it can no longer enter the mounting hole 5. During the design process, it is important to keep the width of the fitting edge as small as possible so that the 2N-sided polygon will not exceed the outline range of the bolt head 3 when it is rotated.

[0028] To better explain Figure 6-9 The structures of the bolt head 3 and the mounting hole 5 with cross-sections of equilateral triangle, triangle and rectangle are shown respectively.

[0029] like Figure 6 and 7 As shown, when the cross-sections of the bolt head 3 and the mounting hole 5 are equilateral triangles, the cross-section of the fixing head 4 can be a regular hexagon or a standard hexagon. Additional sides, such as heptagons or octagons, can also be added to the edges used for connection and contact. When the fixing head 4 has a regular hexagonal cross-section, three of its sides are in contact with the three sides of the bolt head 3. The three sides not in contact with the bolt head 3 are the contact edges mentioned earlier. When the fixing head 4 is a standard hexagon, its three non-contact edges can be parallel to the three sides of the bolt head 3.

[0030] like Figure 8 As shown, when the cross-sections of the bolt head 3 and the mounting hole 5 are equilateral triangles, the cross-section of the fixing head 4 is a regular hexagon, and some sides can also be added; the three shorter sides are the fitting sides.

[0031] like Figure 9 As shown, when the cross-sections of the bolt head 3 and the mounting hole 5 are rectangular, the cross-section of the fixing head 4 is a regular octagon, with the four shorter sides being the fitting sides.

[0032] The cross-sections of the bolt head 3, the fixing head 4, and the mounting hole 5 can also be other shapes, which will not be shown in this article.

[0033] A washer 6 can also be fitted onto bolt 1. The diameter of washer 6 is larger than the maximum width of mounting hole 5.

Claims

1. A single-sided bolt fastening assembly, comprising a bolt (1) and a mating nut (2), characterized in that: The bolt (1) has a fixed head (4) fixed on the side of the bolt (1) facing the screw. The fixed head (4) is an irregular prism with more sides than the polygonal mounting hole (5) on the part to be connected. The projection of the fixed head (4) in the axial direction of the bolt (1) is within the outline of the bolt head (3). The bolt head (3) can pass through the mounting hole (5) and rotate and then retract so that part of the side of the fixed head (4) fits against all the sides of the mounting hole (5) to restrict the rotation and radial movement of the bolt (1). At the same time, the bolt head (3) is limited to the outside of the mounting hole (5).

2. The single-sided bolt fastening assembly according to claim 1, characterized in that: The number of sides of the cross-section of the fixing head (4) is at least twice the number of sides of the mounting hole (5).

3. The single-sided bolt fastening assembly according to claim 1, characterized in that: The width of the side of the fixing head (4) that fits into the mounting hole (5) is smaller than the width of the other sides.

4. The single-sided bolt fastening assembly according to claim 1, characterized in that: Both the bolt head (3) and the mounting hole (5) have triangular cross-sections.

5. The single-sided bolt fastening assembly according to claim 4, characterized in that: The cross-sections of the bolt head (3) and the mounting hole (5) are equilateral triangles.

6. The single-sided bolt fastening assembly according to claim 5, characterized in that: The cross-section of the fixing head (4) is a regular hexagon, with three spaced sides respectively fitting against the three side edges of the bolt head (3).

7. The single-sided bolt fastening assembly according to claim 1, characterized in that: A washer (6) is fitted on the bolt (1), and the diameter of the washer (6) is greater than the maximum width of the mounting hole (5).

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