Metal expansion bolt capable of adapting to wide-range aperture

Abstract

Compared with an existing metal expansion bolt, the metal expansion bolt capable of adapting to the wide-range hole diameter is characterized in that an expansion pipe on the metal expansion bolt is changed into a wedge-shaped head expansion strip and a constraint pipe ring, the maximum expansion value of the expansion bolt can be increased by more than one half of the diameter, and when the expansion bolt is used in concrete punching installation accessories, the expansion value can be increased by more than one half. The situation that fastening is not firm due to the fact that the hole diameter is slightly large is avoided, and the success rate of expansion fastening is almost one hundred percent.

Description

Technical Field

[0001] This invention relates to a hardware fastener, specifically a metal expansion bolt that can accommodate a wide range of hole diameters. Background Technology

[0002] Existing metal expansion bolt fasteners consist of a countersunk screw, an expansion tube, a flat washer, a spring washer, and a nut. The tail of the screw is conical. In use, a hole of the appropriate size is first drilled in the fixed object using an impact drill. Then, the bolt and expansion tube are inserted into the hole. Because the large diameter of the countersunk head on the screw is larger than the inner diameter of the expansion tube, when the nut is tightened, the screw moves outward. The axial movement of the thread causes the conical countersunk head to move, thus creating a large positive pressure on the outer circumference of the expansion tube, expanding it and achieving the purpose of expansion. Friction self-locking occurs between the inner wall of the drilled hole, the expansion tube, and the cone, thereby achieving a fixing effect. When using this type of expansion bolt to install accessories in concrete, if a 14mm diameter expansion bolt is selected, a 14mm diameter hole must be drilled in the concrete. However, when drilling in concrete, it is easy to hit the reinforcing steel bars inside, or the uneven hardness of the concrete, or the presence of particularly soft or hard stones, can cause the drill bit to be squeezed or vibrated, forcing the drilled hole to become larger and coarser. The expansion tube at the rear end of the expansion bolt, if made of thick metal tubing, is difficult to deform and expand. Therefore, it is usually made of thin metal tubing. However, its strength is low, causing the dovetail-shaped expansion tube to bend inward under pressure from the inner wall of the drilled hole when it expands. At this point, the rigid diameter of a 14mm diameter expansion bolt plus the thickness of the outer expansion tube is less than 16mm; the rigid diameter of a 10mm diameter expansion bolt after expansion is no more than 11mm. Furthermore, the elastic diameter and strength of the dovetail-shaped expansion tube are weak, making it very easy for it to become insecure when fastening building components. When insecurity is discovered after tightening, the expansion bolt has already expanded and thickened, making it difficult to remove and replace. If three expansion bolts are needed to tighten a building component, and one is not fully tightened and cannot be replaced, the other two good expansion bolts will also become unusable. It may be necessary to change the position of the building component and re-drill holes, a situation that is common. Moreover, workers often repeatedly loosen and tighten the nuts to try to tighten them, and when they are forced to change positions, it consumes a lot of time and seriously affects work efficiency. Summary of the Invention

[0003] This invention provides a metal expansion bolt adaptable to a wide range of hole diameters to solve the aforementioned problems in the prior art. This metal expansion bolt, with a diameter of 14mm, has a rigid expansion diameter range of 14mm-20mm, making it suitable for drilling holes ranging from 14mm to 20mm. When drilling a 14mm diameter hole in concrete, the tightening effect can reach 100%.

[0004] This invention modifies existing metal expansion bolts by replacing the dovetail-shaped expansion tube made of thin sheet metal with several three-dimensional wedge-shaped expansion strips and restraining rings. The restraining tubes only constrain the wedge-shaped expansion strips; the materials can be thin metal tubes, soft or hard thin plastic tubes, elastic rings, or adhesives instead of restraining rings. One end of the wedge-shaped expansion strip is pointed or flat, gradually thickening towards the middle; for ease of product assembly, both ends can also be pointed or flat wedge-shaped without affecting the expansion effect. During manufacturing, appropriately sized iron wire can be used, or it can be formed by extruding or stamping metal sheets. Because the three-dimensional wedge-shaped expansion strips have a certain thickness, their expansion strength and diameter range are significantly enhanced and increased compared to the dovetail expansion tubes of existing metal expansion bolts, increasing the expansion success rate of this metal expansion bolt from 90% to 100%. Since the few existing metal expansion bolts that fail to expand are not easy to replace, the application of the metal expansion bolts of this invention, which can adapt to a wide range of hole diameters, can significantly improve labor efficiency when installing accessories in large quantities on concrete. In the current context of rising labor costs, this invention has strong practicality. Attached Figure Description

[0005] Figure 1 This is a schematic diagram illustrating the expansion of the metal expansion bolt of the present invention, which can adapt to a wide range of hole diameters.

[0006] Figure 2 This is a cross-sectional structural diagram of the metal expansion bolt of the present invention, which can adapt to a wide range of hole diameters.

[0007] In the diagram: 1-Conical countersunk screw; 2-Wedge-shaped expansion bar; 3-Nut washer; 4-Nut and spring washer; 5-Constraint ring. Detailed Implementation

[0008] This invention relates to a metal expansion bolt adaptable to a wide range of bore diameters, comprising a conical countersunk screw 1, several wedge-shaped expansion strips 2 surrounding its outer periphery, a constraint ring 5, a nut washer 3, a spring washer, and a nut 4. The conical countersunk screw, flat washer, nut, and spring washer are consistent with known prior art; the core improvement of this invention lies in the wedge-shaped expansion strips and the constraint ring.

[0009] In this embodiment, the wedge-shaped expansion strip is made of 4mm diameter iron wire, which is extruded into 40mm long segments with wedge-shaped ends in a nail-making machine, and then laterally extruded into a 3mm thick flat oval strip, finally forming a wedge-shaped expansion strip with a middle thickness of 3mm, a width of 5mm, and a length of 40mm. The constraint tube ring is made of elastic flexible tubing with an outer diameter of 8mm and an inner diameter of 7.5mm, cut into 10mm segments. In this embodiment, the countersunk screw has a diameter of 4mm, the thickest countersunk position has a diameter of 9mm, and the total length is 60mm. Four wedge-shaped expansion strips are used to surround the countersunk screw with the nut and washer already assembled, and then the outside is constrained by the expanded elastic constraint tube ring to form an expansion assembly; alternatively, an adhesive material (such as polyurethane foam) can be used to bond the wedge-shaped expansion strips around the countersunk screw to form an expansion assembly, as long as the components do not fall apart before use. This completes the assembly of the metal expansion bolt of the present invention, which can adapt to a wide range of hole diameters.

[0010] In use, first drill a 10mm diameter hole in the fixed body using an impact drill (hammer), then insert the metal expansion bolt of this embodiment into the hole. Since the large diameter of the countersunk screw is larger than the inner diameter of the surrounding wedge-shaped expansion strips, when the nut is tightened, the screw moves outwards. The axial movement of the thread drives the conical part to move, causing the adhesive to break or the restraining ring to be opened. The countersunk screw creates a large positive pressure inside the wedge-shaped expansion strips, increasing the distance between them and achieving the expansion purpose. Due to the small angle of the countersunk screw, under the limitation of the hole diameter, frictional self-locking occurs between the wedge-shaped expansion strips and the conical countersunk screw, thus achieving a fixing effect. When the drilled hole diameter expands due to hitting the reinforcing steel in the concrete, continue tightening the nut. When the thickest diameter of the countersunk screw (9mm) meets the thickest part of the surrounding wedge-shaped expansion strip (3mm), the rigid diameter of the expansion reaches 9mm + 3mm + 3mm = 15mm. In summary, the present invention can achieve an expansion tightening success rate of almost 100% for metal expansion bolts with a wide range of hole diameters. This embodiment is merely a specific specification example illustrating the invention and does not limit the scope of protection of the invention.

Claims

1. A metal expansion bolt adaptable to a wide range of hole diameters comprising a nut, a nut washer, a countersunk screw, characterized in that: It also includes several wedge-shaped expansion strips distributed on the outer periphery. The nut, nut washer, countersunk screw and wedge-shaped expansion strips constitute an expansion assembly. The outer periphery of the expansion assembly is constrained by a constraint tube ring to form a complete expansion bolt.

2. The metal expansion bolt of claim 1, wherein: Both ends of the wedge-shaped expansion strip are wedge-shaped heads.

3. The wide range of aperture adaptable metal expansion bolt according to claim 1, characterized in that: The constraint ring is made of a thin metal tube, a soft plastic tube, a hard plastic tube, or an elastic material tube.

4. The wide range of aperture adaptable metal expansion bolt according to claim 1, characterized in that: The constraint ring is replaced by an adhesive that bonds the wedge-shaped expansion strip to the countersunk screw.

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