What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The Greek mathematician Arkutas once described the principle of screw, screw, screw. In the first century AD, the Mediterranean world had begun to use wood screws, screws, and screws in screw presses that could press olive oil from olives, or make wine from grapes. Before the fifteenth century, metal screws, screws, screws were rarely used as fasteners in Europe. Rybczynski (Rybczynski) proves that hand-held screwdrivers and screwdrivers existed in the Middle Ages (at the latest AD 1580), but it was not until the eighteenth century that threaded fasteners were commercialized and began to be widely used. . Before threaded fasteners were widely used, there were many different ways of tightening. Mostly related to woodworking and forging, and less to machining, concepts such as dowels and pins, wedges, tenon and tenon, dovetails, nails, forge welding, and others are tied with leather or fiber and tied together. Before the mid-nineteenth century, ships were built with cotter pins, pin bolts, or rivets. There were also adhesives, but not as many as they are here today. Metal screws, screws, and screws became commonly used fasteners after the use of machine tools in the 18th century to mass-produce screws, screws, and screws. This technology developed around the 1760s and 1770s, along two separate processes. Approaches, but quickly converged: wood screws, screws, screws (metal screws for wood fixing, screws, screws) are machined with single-purpose, high-yield machines, and low-volume, mold shop style production V-Thread Machine Screws, Screws, Screws, can choose from a variety of different pitches.
The fixing screw proposed by Guangdong Yueluo Hardware Industry Co., Ltd. has a screw body 1, and the axial surface of the screw body 1 is formed with extending screw teeth 6, and the axial surface is a column along the central axis direction of the cylinder of the screw body 1. The body surface has a hemispherical screw tail 7 at the bottom, and a screw head 2 at the top. The upper surface of the screw head 2 is provided with a slot (not shown). The screw body 1 is composed of the upper tapered rod 4 and the lower cylindrical screw 5. The tapered rod 4 is an inverted cone, the diameter of its circular upper surface and the diameter of the screw mounting hole 10. equal. The fixing screw also has a washer 3, the washer 3 is arranged between the screw head 2 and the screw body 1, the lower surface of the cylindrical washer 3 has a number of teeth 8, the teeth 8 are along the The upper surface of the inverted cone of the tapered rod 4 and the edge of the washer 3 are connected to form a straight convex strip 15 extending outward; the convex strip 15 can also be designed in an arc shape. The fixing screws for installation proposed by Guangdong Yueluo Hardware Industry Co., Ltd. can be made of metal materials in one piece. As shown in Figure 3, it is a schematic diagram of the installation of Guangdong Yueluo Hardware Industry Co., Ltd. for PCB board fixing. When installing, first pass the screw body 1 of the fixing screw through the mounting hole 10 and the copper column 11 provided on the PCB board 9, so that the tail 7 of the screw reaches the mounting hole 13 on the casing 12, and then use the tightening tool 14 to insert the screw At the notch on the top of the head, forcefully press the inverted cone design taper rod 4 of the screw body 1 into the mounting hole 10, so that the tail 7 passes through the mounting hole 13. Due to the outer diameter D at the bottom of the taper rod and the screw mounting hole The aperture size of 10 is equal, and the fixing screws are pressed and fixed, so that the PCB board 9 can be automatically corrected in the process of fixing its front, back, left and right deflections, and the accuracy of the installation position of the PCB board 9 can be ensured. As shown in Figure 4, after the fixing screw is screwed into the casing, the washer 3 is fully contacted and pressed on the PCB board 9, and the PCB board 9, the copper column 11 and the casing 12 are firmly connected together without sliding. . The teeth 8 on the washer 3 are in full contact with the surface of the PCB board 9, so that a ground wire path is set up between the PCB board 9 and the casing 13 by the metal fixing screw 1, thereby ensuring that the PCB board 9 is fully grounded , the design of the teeth 18 on the washer 3 also has a non-slip function. The fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. make use of the cooperation, friction and electrical conductivity in the mechanical connection, which fully guarantees the firm installation of the PCB board and the chassis and the good grounding of the PCB board. Moreover, the ellipsoid tail of the fixing screw The surface is relatively smooth, even if the mounting holes are exposed, it will not cause scratches on the hands and desktop. The above is only the embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., and does not limit the scope of Guangdong Yueluo Hardware Industry Co., Ltd., any equivalent structure made by using the contents of the description and drawings of Guangdong Yueluo Hardware Industry Co., Ltd. or etc. Effective process transformation, or direct or indirect application in other related technical fields, are also included in the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd.
Guangdong Yueluo Hardware Industry Co., Ltd. relates to a square nut fastener for cable bridge installation, which is characterized in that it includes an upper plate body and a U-shaped jacket, and the upper plate body is provided with a downwardly protruding connecting cylinder, The two side plates of the U-shaped jacket are connected to the connecting cylinder, and the center line of the two side plates is located on the center line in the length direction of the upper plate body; the bottom of the U-shaped jacket is a wave-shaped elastic plate, which is a wave-shaped elastic plate It is fixedly connected on the two side plates, and the space enclosed by the two side plates of the U-shaped jacket, the wave-shaped elastic plate and the bottom of the connecting cylinder is the installation position of the square nut. Guangdong Yueluo Hardware Industry Co., Ltd. has a simple and reasonable structure, and is extremely convenient and flexible to operate; it does not occupy the bottom space of the C-shaped steel after installation, which increases the variety of installation, and can be applied to square nuts of different thicknesses, and the installation is firm.
screw is a common threaded connection part, which is mainly used to fix a part on the connection body. When it is necessary to connect, use the screw to pass through the hole on the connected parts, and screw the external thread on the screw into the connecting body to tighten it; The coupling part is separated from the coupling body. Existing common tools for screw disassembly and assembly are generally adjustable wrenches, open-end wrenches, Torx wrenches, socket wrenches, Allen wrenches, flat-blade screwdrivers, cross-shaped screwdrivers, etc., and a screw can only be disassembled with one or one type of tool. Assembly work; when the types of tools are not complete, the screw disassembly and assembly work is difficult to complete, and the screw disassembly and assembly work is greatly limited by the tools.
The above content is uploaded by Yueluo or the Internet. If there is any copyright issue, please contact [email protected].
