What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
For common screw belts, please refer to the Central Taiwan Announcement No. 327449 on February 21, 1998, Screw Belts (2), which includes a main body with multiple grooves on the side of the main body for the purpose of locking screw tools to drive the belt. A toggler; and a plurality of nail grooves are arranged on the nail belt so that the screw planting is arranged in an arrangement, and the nail grooves are all provided with through holes, and the through holes extend downward with a ring to form a support portion for the screws; and the It is surrounded and provided with a plurality of cutting grooves, which is beneficial for the screw to be rotated through the nail groove; and it is characterized in that the nail groove is located on the inner wall surface of the surrounding and is provided with a plurality of lobes, and these lobes are implanted in the screw. In the nail groove, the leaflet supports the screw, so that the screws with different outer diameters are fully supported and positioned by the leaflet; and/or the upper part of the leaflet is inclined or curved, so that a depression is formed above the ring to support the screw The arc surface or tapered surface of the neck can make the screw more stable to be supported.
T-bolt is a common fastener, which is mostly used where there is a T-slot on the workbench or where the connection can only be made from the side to be connected. However, it has the following problems in the actual production and processing process. 1. The T-bolt manufactured according to the current GB37-88 is used in conjunction with the T-slot on the worktable, which is easy to damage the T-slot on the worktable. 2. According to the observation and investigation, it is found that 90% of the damage to the T-bolt manufactured by GB37-88 is thread damage during use, and the T-shaped part is rarely damaged, resulting in a waste of raw materials. SUMMARY OF THE INVENTION The purpose of the present invention is to solve the problem that the current composite T-bolt is easy to damage other equipment and cause waste of raw materials in the actual use process, and to provide a simple structure, easy to use, safe and reliable, and not easy to damage other equipment. , thereby saving raw materials and other advantages of composite T-bolts. In order to achieve the above purpose, the present invention adopts the following technical scheme: a composite T-bolt, which includes a bolt, and one end of the bolt is connected with the T-shaped block cockroach. The T-shaped block is provided with a tapered hole, and the connection between the bolt and the T-shaped block is a cone, which is matched with the tapered hole. The utility model combines the two parts of the T-shaped block and the threaded bolt through the T-shaped block and the taper hole and the cone on the bolt to automatically lock the two parts before use. When the threaded part of the bolt is damaged, only the threaded bolt needs to be replaced. That's it. Compared with the domestic T-shaped bolts currently produced in the manufacturing process, the utility model solves the problems of complicated manufacturing processes and waste of raw materials. It is well known that the manufacture of T-bolts requires processing such as forging, turning, milling, and heat treatment. Since the composite T-bolt is used in combination with the T-block and the bolt, and the T-block is rarely damaged, after purchasing or manufacturing the T-block once, you only need to purchase or manufacture the bolt in the future. Compared with the T-bolts currently produced in China, the composite T-bolts can better protect the T-slots on the working surface. Because the T-bolt currently produced in China will rotate a certain angle around the axis of the T-bolt when fixing the object, the T-bolt will rotate at a certain angle, thereby reducing the contact between the T-bolt T-shaped surface and the T-slot stress surface of the working face. surface, causing stress concentration on this surface. The composite T-bolt avoids the above problems due to the increase of the guide surface, thereby protecting the T-slot. The beneficial effects of the utility model are: 1. Saving raw materials. 2. Reduce processing costs. 3. Simplify the technological process. 4. Protect the T-slot.
The difference between high-strength bolt friction type and pressure-bearing type connection: High-strength bolt high-strength bolt connection is to clamp the plate of the connecting plate through a large tightening pre-pressure in the bolt rod, which is enough to generate a large friction force, thereby improving the connection. The integrity and stiffness of the bolt can be divided into two types: high-strength bolt friction type connection and high-strength bolt pressure type connection according to different design and force requirements when subjected to shear force. The essential difference between the two is that the limit state is different, although It is the same kind of bolt, but it is very different in terms of calculation method, requirements, and scope of application. In the shear design, the friction type connection of high-strength bolts is the limit state when the external shear force reaches the possible maximum friction force provided by the bolt tightening force between the contact surfaces of the plates, that is, the internal and external shear force of the connection is guaranteed not to exceed maximum friction. The plate will not undergo relative slip deformation (the original gap between the screw and the hole wall is always maintained), and the connected plate will be elastically stressed as a whole. In the design of shear resistance, the external shear force is allowed to exceed the maximum friction force in the high-strength bolt-bearing connection. At this time, relative slip deformation occurs between the connected plates until the bolt rod contacts the hole wall, and then the connection depends on the bolt rod. The shearing of the body and the bearing of the hole wall and the friction between the contact surfaces of the plates jointly transmit the force, and finally the shearing of the shaft or the bearing of the hole wall is regarded as the limit state of the connection shearing. In a word, friction type high-strength bolts and pressure-bearing high-strength bolts are actually the same type of bolts, but whether the design considers slippage. Friction type high-strength bolts can never slide, and the bolts do not bear shear force. Once slipped, the design is considered to reach a state of failure, which is technically mature; pressure-bearing high-strength bolts can slide, and the bolts also bear shear force, and the final damage is equivalent to ordinary Bolt failure (bolt shearing or steel plate crushing).
However, Yueluo still feels that there should be room for improvement for the screw improvement and screw that integrates stability, labor, fast and multi-function in the above two cases; for example, No. 556784 screw improvement Although the rod has the function of cutting and collecting chips, when the screw starts to screw into the object such as wood, it is hindered by the hardness of the object's tissue, so the staff still needs to exert considerable force, resulting in the lock. In the solid operation, there is still a lack of difficulty in screwing in operation; another example, new cases such as No. 289410 screw that integrates locking, stability, labor, fast and multi-function, although the rod has the structural function of cutting and chip removal, it is The rod part is screwed into the middle section to the rear section of the object. Since the debris cannot be discharged, the rod part pushes the outer part of the object to the surrounding tissue of the object, so that the object expands outwards and even seriously damages the appearance of the object.
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