flat washer is a part that is placed between the connected part and the bolt to protect the surface of the connected part from being scratched by the nut and to disperse the pressure of the nut on the connected part. At present, a flat washer in the prior art generally includes a washer body; the washer body has a bolt hole in the middle for a bolt to pass through. Although the flat washer of the above structure has a simple structure, it still has a disadvantage. When the flat washer is cushioned between the connected part and the bolt, the bolt head is usually exposed outside the connection part, so the bolt head is easy to It is damaged under the impact of external force, thus affecting its fixing effect.
rivet assembly device is provided with a base, the middle of the base is provided with a vertical groove, the bottom wall of the vertical groove extends forward and a horizontal convex block is suspended; the top surface of the convex block is fixed with a vertical rivet Needle and a guide column, the column body of the guide column is covered with a return spring; a downwardly open sliding block is mounted on the convex block, and the upper ends of the rivet needle and the guide column respectively protrude into the sliding block on the top wall of the sliding block. In the riveting pin hole and the guide hole, the inner wall of the riveting pin hole is provided with a large upper and a lower small horizontal step; the upper part of the bottom wall of the vertical groove is provided with a guiding limit rib. Guangdong Yueluo Hardware Industrial Co., Ltd. sets the rivet needle under the workpiece, and uses the upper die punch to press down the workpiece, and the rivet needle completes the operation of the rivet, omitting the operator to turn over and carry the rivet terminal board, thus effectively avoiding the rivet from The phenomenon that the rivet hole comes out. In addition, during operation, the workpiece is placed on the top surface of the slider, and the workpiece guide limit ribs and guide columns are used as shafts and radial limiters respectively. The riveting quality is good, and the purpose of saving time and labor and high efficiency is achieved.
Yueluo relates to a self-tapping screw according to the preamble of claim 1. A self-tapping screw is known from EP0623759B1, the ratio of the outer diameter to the smaller diameter of the self-tapping screw is about 1.25-1.5, the ratio of the outer diameter to the pitch lead is about 1.5-1.6 and the thread The flank angles of , are < 50° and ≥ 35°. EP0433484B1 proposes a self-tapping screw whose thread is provided with cutting teeth of approximately arcuate design, and the cutting edge and the thread crest are at the same horizontal position and are set in opposite directions. One purpose of Yueluo is to realize a general type of self-tapping screw so that it can be screwed particularly easily into holes drilled in concrete or other materials such as bricks and the like. According to Yueluo, this object is achieved by the features in the characterizing part of claim 1, and surprisingly, it has been found that the parallel arrangement of the flanks, ie with a flank angle of about 0°, will make screwing particularly easy when screwing in , especially if the diameter of the hole varies within an allowable tolerance. One reason may be due to the fact that there is no lateral pressure on the material screwed into the thread, even if threads of different depths are cut in concrete or other materials such as brick, chipped plywood, or hardwood. The thread cuts into the material over its entire width by cutting grooves. In particular according to the embodiment of claim 11 the result is that the material cut out when screwing in the screw can be discharged without any accumulation, the dependent claims reflecting many advantages of further embodiments.
When using ordinary hexagon head bolts or ordinary T-bolts with the oval groove structure, the bolts need to be inserted from the back of the groove. When the bolts cannot be inserted from the back of the groove due to the structural limitations of the steel base or the platform itself, it is often necessary to open the installation surface. Large diameter hand holes allow for easy mounting of bolts, which weakens the inherent strength and rigidity of a steel base or platform.
The anti-rotation T-bolt includes a screw rod and a head. An anti-rotation protrusion is designed at the connection between the head and the screw. The cross-section of the anti-rotation protrusion is a square corner with the screw radius as the side length. One anti-rotation protruding shoot can be designed, or two can be designed. In order to ensure the uniform force of the bolt, two are designed.
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