Pin-type flanged lag screw bolt

Abstract

This product primarily relates to the joining of CLT (Cross-Laminated Timber) structural elements in highly earthquake-resistant wooden buildings. CLT refers to a wood-based material called "cross-laminated timber," which is made by laminating and bonding multiple layers of plank-shaped wood vertically and horizontally. It is characterized by its wide, thick, and large, single-piece form, enabling large-span roofs, floors, and walls. Due to these characteristics, CLT is used as a highly earthquake-resistant structural material in modern commercial buildings, offering lighter weight and superior insulation compared to steel frames. It is also used in large-scale wooden buildings. It is becoming popular as "architecture," and the current construction methods include 1) a structure composed only of structural panels for the roof, walls, and floor, and 2) a structure that is constructed in combination with a wooden frame. In the case where only structural panels are used, the connection between the roof and walls, and between the walls and floor, or in the case where a wooden frame is used, the connection between the beams and floors, beams and walls, and walls and columns, is generally done by driving long nails or long screws with flat plates or L-shaped steel plates attached. As mentioned above, the construction of this product in CLT buildings has mainly involved on-site work based on a lot of manual work, and each Considering that the joining of panels involved the use of numerous flat steel plates for joining, and a considerable amount of work with long nails and screws, and that each panel itself was wide, thick, and heavy, and that the exterior wall substrate involved the treatment of a considerable number of flat steel plates, protruding nail heads, or screw heads, making it an extremely complicated and difficult task when working at heights, this product was created. Regarding the joining of each panel, much of the work was pre-fabricated in the factory, and this product is a pin-driven flange-type lag screw bolt designed to enable safe and efficient bolt and steel pin joining during on-site work at heights, while also aiming for high rigidity. Its features include a circular flange on one end for use as a round washer, with a female thread inside the center of the flange having a fixed inner diameter, length, and depth, and on the outside, a lag screw shape with high, large threads and a wide thread pitch that bites into wood material, with a fixed length; and subsequently, a round bar-shaped shaft with the root diameter of the threads forming the outer diameter, with a fixed length, and at least one through-hole for driving in a steel pin, thus integrating two features into a single shape.In the joining of roof or floor panels to wall panels in CLT construction, pre-drilled holes slightly larger than the diameter of the round bar shaft (which is the root diameter of the pin-driven flanged lag screw bolt) are made in the factory for the roof, floor, and wall panels. These pre-drilled holes are then used as through holes, and the pin-driven flanged lag screw bolts are rotated and inserted in advance. During construction, the round bar shaft is inserted into the pre-drilled holes at a certain depth in the upper part of the wall panels erected on both sides. After that, steel drift pins are driven into the pre-drilled pin-insertion locations in the wall panels, thereby easily joining the roof or floor panels to the wall panels. The main body shape of the pin-driven flange-type lag screw bolt is such that a circular flange portion with a fixed outer diameter and thickness, which serves as a round washer larger than the outer diameter of the external thread, is integrally formed on one end of a bolt of a fixed length, and the neck portion of the threaded part is attached to the other end of the bolt, and the neck portion and the outer diameter of the bolt's external threaded part are the same diameter, and the threads are tall and large, and the thread pitch is wide, and the threaded part has the shape of a lag screw, which bites into wood material when rotational force is applied and advances while cutting threads of the same shape, and the threaded part has a fixed outer diameter and root diameter and extends for a fixed length, and then a round rod-shaped shaft which is integrally formed with the root diameter of the threaded part as the outer diameter and extends for a fixed length to the end, and a through hole of a fixed diameter for pin insertion is machined at a fixed position from the end of the shaft, and from the tip of the flange portion, an inward portion is formed with respect to the center of the flange portion. This pin-driven flanged lag screw bolt is characterized by having a male thread of a fixed outer diameter and a female thread that can be fitted into it, both of which are machined to a fixed length and depth. When joining panels using this pin-driven flanged lag screw bolt, a pilot hole is drilled in the panel of the attached wood material with a diameter slightly larger than the diameter of the root of the lag screw-shaped bolt and the shaft of the same diameter. After countersinking to match the shape and thickness of the circular flange portion, the flange portion of the pin-driven flanged lag screw bolt is rotated using a jig. The flange portion has a square groove with a fixed depth and a width slightly larger than the outer diameter of the inserted bolt, and a small diameter through hole around the periphery. By rotating and inserting the bolt into the pilot hole using a dedicated jig and power tool, and then screwing it in and fixing it in place, it becomes one with the wood material, eliminating looseness caused by shrinkage due to the aging of the wood.This product ensures long-term structural integrity by maintaining the load-bearing capacity of the joints of each structural panel and eliminating looseness in the joints caused by seismic vibrations, thereby enabling the long-term structural integrity of the building. Its features include the ability to customize the overall length to match the thickness of each structural panel, the outer diameter, root diameter, thread pitch, and thread length of the threaded section according to the required load-bearing capacity, the diameter of the internal female thread, the length of the round bar shaft, and the number of mounting pin holes. Furthermore, using high-strength hexagonal bolts for the male threads that engage with the internal female threads during construction significantly increases the joint strength, resulting in numerous advantages. It can also be used in conjunction with conventional CLT construction methods using sheet steel or L-shaped steel plates with nails or screws, depending on the application.

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