Rod connection unit

Abstract

The utility model relates to connecting units for assembling various frames, trusses, etc., intended for use both separately and as part of certain products. The utility model is a connecting unit for rods in a rod system. The primary purpose of the utility model is use in frames, trusses, and framing for furniture of various purposes, including use in prefabricated metal frames, frames, and trusses, as well as those made of other materials (wood, polymers, composite materials, etc.), for shelving, tables, desks, chairs, benches, stools, beds, sofas, props, hangers, etc. for domestic and industrial purposes. The connecting unit of the rods is characterized in that it is formed by means of a rod (1) and a rod (2) connected to it at an angle of 30-150 degrees.Each rod (1, 2) has a cross-section in the form of a convex quadrangle with opposite sides parallel and adjacent sides perpendicular. The rod (1) and rod (2) are connected by means of a section of rod (1) that is enclosed and placed in a cavity of rod (2). Rod (2) is fastened to rod (1) by means of holes made in each of them and fasteners used with them. The axes of the holes in rod (2) and the corresponding holes in rod (1) are located perpendicular to the longitudinal axis of rod (1). The arrangement and number of said holes, as well as fasteners used with these holes, ensure the basing of rod (1) relative to rod (2) in the absence of degrees of freedom. The utility model solves the problem of creating a connection unit for rods in a rod system with the possibility of assembly and disassembly.Such a joint may include a joint connecting both solid and hollow elements (rods), including a joint connecting two pipes (pipe sections), each of which has a rectangular cross-section, as well as for standardized, typical pipes and shaped pipes. This design simplifies, increases strength, reliability, and precision, and improves the maintainability of the joint. Additionally, the utility model expands the arsenal of technical means. The ability to connect at an angle of 30-150 degrees is achieved by arranging the axes of the connecting elements (fasteners) perpendicular to the plane of the frame (truss) rods. Strength and reliability are increased by increasing torsional rigidity. Improving the precision of the joint can be achieved by adjusting the relative positions of the joint components.The design simplification objective was achieved by reducing the number of complex-to-manufacture parts, thereby improving manufacturing processability. This improved processability results in simplified assembly and disassembly. The ability to easily replace individual components of the connecting unit in the event of damage improves its maintainability. The ability to repeatedly assemble and disassemble the connecting unit was achieved by incorporating parts and elements capable of participating in such assemblies and disassemblies without affecting their technical parameters (or changing their technical parameters). Fasteners for detachable connections may be used to connect the components of the utility model. 12 decimal places, 5 figs.

Description

[0001] This utility model relates to connecting assemblies for assembling various frames, trusses, etc., intended for use both separately and as part of other products. Thus, the utility model is a connecting assembly for rods in a rod system. The primary purpose of the utility model is use in frames, trusses, and other furniture framing for various purposes. Application is also possible in prefabricated metal frames, framing, and trusses, as well as those made of other materials (wood, polymers, composite materials, etc.), for shelving, tables, desks, chairs, benches, stools, beds, sofas, props, hangers, etc. for domestic and industrial purposes, where strength, stability, and reliability under static and dynamic loads are important. Possible implementation options for the utility model in frames and trusses.

[0002] A frame is a two- or three-dimensional structure containing rigid connections between its elements, supporting them and giving them shape. Frame elements can experience loads associated with tension, compression, and bending. Thus, a frame is a planar or spatial geometrically invariable rod system whose elements (posts, beams) are rigidly connected to each other at some or all nodes. The system is a set of elements that are interconnected and connected to each other. This set of elements forms a certain integrity, a unity. Frame rods simultaneously experience axial forces and bending, with bending loads typically predominating. Frames typically serve as load-bearing structures, supporting static loads.

[0003] A truss (in structural mechanics) is a rod system that remains geometrically unchanged after its rigid nodes are replaced with hinged ones. In the truss elements, in the absence of rod misalignment and off-node loading, only tensile and compressive forces arise. Trusses are formed from straight rods connected at nodes to form a geometrically unchanged system. In this system, load is applied only at the rod connections (nodes) and only in the form of point forces; for example, these nodes can serve as supports for the truss itself.

[0004] For both a frame and a truss, a rod is an elongated body, two of whose dimensions (height and width) are small compared to the third dimension (length). Conventionally, a rod can be represented as a set of parallel or nearly parallel longitudinal fibers. The cross-section of the rod, normal to the fibers, is the cross-section. The locus of points passing through the centers of gravity of the cross-sections is the axis of the rod. A rod working primarily in bending is also called a beam or a bar. A vertical rod working primarily under axial forces is called a strut or column, while an inclined rod is called a diagonal. A horizontal rod working in compression is called a strut, and one working in tension is called a tie rod. According to the shape of the axis, rods are classified as straight, curved, and broken. A straight rod can have either a constant or variable cross-section, or a cross-section that changes in steps along the length of the rod.A curved rod is a design model for arches, ring foundations, ring stiffeners, etc. A broken rod is a support beam for something. Solid and thin-walled rods are distinguished by their relative cross-sectional dimensions. Solid rods come in a variety of cross-sectional shapes: convex polygonal (polygonal), trapezoidal, rectangular, round, ovoid, T-shaped, I-shaped, cruciform, and others. Thin-walled rods come with open or closed cross-sections. The main distinguishing feature of thin-walled rods is the need to account for torsion in their design.

[0005] Rod systems: By rod connection type: with rigid connection (frames); with hinged connection (trusses, lattice structures, shells, domes, structures, etc.). By loading pattern: planar, supporting external loads acting only in the plane of the rod system; spatial, supporting external loads of any direction. By degree of static determinacy: statically indeterminate, statically determinate. By purpose: span, combined, support.

[0006] Prefabricated and disassemblable connecting assemblies are known from the prior art, including those used in frames, trusses, and various metal frameworks, including those for furniture. The closest in design are assemblies with a female connection. However, these known designs are either more complex, for example, due to the female section having its own, additional connection to the rod, or less durable and reliable, including for forming the required angle.

[0007] A "Connecting Structure for a Bed" (GB 2636929 A, priority dated 2024.12.17) is known. The document discloses a connecting assembly comprising a first element of rectangular cross-section and a second element of rectangular cross-section. These elements are connected at a 90-degree angle by inserting the end of the second element, through an additional connector, into a blind hole (cavity) in the side wall of the first element. The elements are fastened together by screws located along the axis of the second element.

[0008] Design disadvantages include low torsional rigidity and high deflection under load, resulting in limited strength and durability. To use screws with an inserted element, the inserted element requires an additional wall at its end to accommodate the threaded holes. This complicates production and maintenance. The placement of the fastening screws along the inserted element axis results in a fixed 90-degree angle. Furthermore, the usability of this connection may be limited due to difficult access to its screws.

[0009] The claimed utility model is a joint capable of assembly and disassembly, enabling the connection of two elements at an angle of 30-150 degrees, each of which functions as a rod in a rod system. This joint is a joint for connecting rods in a rod system. Such a joint may include a joint connecting both solid and hollow elements (rods) at an angle of 30-150 degrees, including a T-joint. For example, a joint connecting two pipes (two pipe sections), each of which has a rectangular cross-section. The joint must be capable of being made using standardized, typical pipes and profile pipes. Another objective of the utility model is to simplify the design, increase the strength, reliability, and precision, and improve the maintainability of the joint. Additionally, the utility model addresses the problem of expanding the arsenal of technical means.

[0010] Ensuring the ability to connect at an angle of 30-150 degrees is achieved by arranging the axes of the connecting elements (fasteners) perpendicular to the plane of the frame (truss) rods. Strength and reliability are increased by increasing torsional rigidity. Increasing the accuracy of the connection assembly can be achieved by adjusting the relative positions of the assembly parts. Simplifying the design is achieved by reducing the number of complex parts, thereby improving manufacturing efficiency. The connection assembly can be constructed using standard profiles and pipes and using standard manufacturing operations. Improved operational efficiency results in simplified assembly and disassembly processes. The ability to easily replace individual components of the connection assembly if damaged improves its maintainability.The task of enabling repeated assembly and disassembly of the connecting unit is solved by incorporating parts and elements in its design that can be assembled and disassembled without affecting their technical parameters (or changing their technical parameters). Fasteners (products) for detachable connections can be used to connect the utility model components.

[0011] The objectives are achieved by the fact that, according to the utility model, the device “Rod connection unit” is characterized by the fact that,

[0012] that it is made by means of rod 1 and rod 2 connected to it at an angle of 30-150 degrees,

[0013] each rod 1, 2 is made with a cross-section in the form of a convex quadrangle, in which the opposite sides are parallel, the adjacent sides are perpendicular,

[0014] the connection of rod 1 and rod 2 is carried out by means of the section of rod 1, which is covered, being placed in the cavity of rod 2, while the fastening of rod 2 to rod 1 is carried out by means of holes made in each of them and fasteners used with them (for example, a screw, a bolt, a nut),

[0015] in this case, the holes in rod 2 and the corresponding holes in rod 1, with their axes, are located perpendicular to the longitudinal axis of rod 1, (that is, each hole in rod 2 and each corresponding hole in rod 1 with its axis is located perpendicular to the longitudinal axis of rod 1),

[0016] The location and number of the specified holes, as well as the fasteners used with these holes, ensures the basing of rod 1 relative to rod 2 in the absence of degrees of freedom in the connection.

[0017] It is possible that the connecting node of the rods is made by means of rod 1 and rod 2 connected to it at an angle of 90 degrees,

[0018] the opening that allows access of the section of rod 1 to the cavity of rod 2 corresponds to the cross-sectional shape of rod 1.

[0019] It is possible that the fastening of rod 2 to rod 1 is carried out by means of holes made on each side of the enclosing section of rod 2, mating holes made in rod 1, fasteners used with all these holes,

[0020] holes made on opposite sides of the enclosing section of rod 2 are coaxial in pairs.

[0021] It is possible that on each side of the enclosing section of rod 2 there are two openings, and there are also two corresponding openings made in rod 1.

[0022] It is possible that rod 1 is made of pipe, rod 2 is made of pipe.

[0023] It is possible that rod 1 is made of a pipe with a rectangular cross-section, and rod 2 is made of a pipe with a rectangular cross-section.

[0024] It is possible that rod 2 is made of a pipe with a rectangular cross-section of (10-200) x (10-200) mm, the pipe wall thickness is 0.5…5 mm, rod 1 is made of a pipe with a rectangular cross-section of (10-200) x (10-200) mm, the pipe wall thickness is 0.5…5 mm.

[0025] It is possible that the counter holes made in rod 1 are threaded, and the fasteners used with them are threaded.

[0026] It is possible that the counter holes made in rod 1 are equipped with rivet nuts, and the fasteners are screws.

[0027] It is possible that the covered section of rod 1 is designed with the possibility of elastic deformation, ensuring the possibility of a backlash-free connection of rod 1 with rod 2.

[0028] It is possible that rods 1, 2 are made of structural steel, fasteners are made of structural steel.

[0029] The rod connection assembly may have a protective coating. It's also possible that the protective coating is polyester powder paint.

[0030] The utility model is illustrated by drawings.

[0031] Fig. 1 - assembled connection unit of rods (1 and 2), axonometric projection;

[0032] Fig. 2 - rod connection unit, fasteners (screws 4) are shown separately, axonometric projection;

[0033] Fig. 3 - rod connection unit assembled, side view, in section, fasteners: screws (4) with flat heads and rivet nuts (3);

[0034] Fig. 4 - rod connection unit assembled, disassembled, axonometric projection;

[0035] Fig. 5 - Pull-out strength comparison graph. Threaded holes and rivet nuts for wall thicknesses of different sizes.

[0036] The utility model comprises a unit formed by rod 1 and rod 2 connected to it at an angle of 30-150 degrees. The rods are connected by a section of rod 2 enclosing a section of rod 1. Rod 1 is also located within the cavity of rod 2. Rod 2 is fastened to rod 1 by holes formed in the enclosing section of rod 2, mating holes formed in rod 1, and fasteners used with all of these holes. The arrangement and number of these holes, as well as the fasteners used with these holes, ensure the alignment of rod 1 relative to rod 2 without degrees of freedom in the connection.

[0037] The figures show: rod 1 is made of a pipe (from a section of a pipe), rod 2 is made of a pipe (from a section of a pipe), they are fastened using rivet nuts 3 and screws 4.

[0038] Each rod 1, 2 has a cross-section in the form of a convex quadrilateral, with opposite sides parallel and adjacent sides perpendicular. Such quadrilaterals include, among others, a rectangle or a square. The connection may involve both solid (e.g., a bar) and hollow elements, such as a pipe or pipe sections. The corners of each rod 1, 2 may be rounded or slightly modified in the same way. A solid rod can also be connected to a hollow rod. At the connection point, the cross-sectional area of ​​rod 2 is greater than that of rod 1.

[0039] Both the longitudinal axes of rods 1 and 2 and the sides of rods 1 and 2 lying on intersecting planes are positioned at an angle of 30-150 degrees. This means that the utility model allows for a connection angle not only of 90 degrees but also any other angle, for example, any angle between 30 and 150 degrees. This is made possible by arranging the fasteners (screws, bolts, rivets) connecting rods 1 and 2 perpendicular to their longitudinal axes and perpendicular to the longitudinal axis of rod 1. The ability to change the position from 30 to 150 degrees can also be achieved, for example, by using oblong rather than round fastening holes in rod 2. Such holes allow for radial movement.

[0040] The connection between rod 1 and rod 2 can be accomplished by positioning the male end of rod 1 within a cavity in rod 2, which may be either through or blind. In this case, the end portion of rod 1's end section may have either right angles or rounded corners, allowing for rotation of rod 1 relative to rod 2.

[0041] A 90-degree angle is most likely to be used. The connection between rods 1 and 2 is detachable, but this connection could also be made conditionally detachable, for example, by rivets. Thus, the utility model utilizes a female connection, in which one rod encloses a section of another rod. The enclosed section of the rod can be either its end or any other section. This ensures a larger contact area and, consequently, high connection strength. Increasing the size of the vertical axis of the connection (fastening) makes the utility model more rigid.

[0042] To impart a specific and strictly fixed relative position (basing) to rod 1 and rod 2 by means of holes and fasteners (products) used with them, a necessary and sufficient condition shall be the presence of one hole on each side of the female section of rod 2, and, accordingly, the presence of mating holes in the male section of rod 1, while the holes located on opposite sides of rod 2 shall not be coaxial. Also, for basing, a necessary and sufficient condition may be the presence of two holes on one side of the female section of rod 2, and, accordingly, the presence of mating holes in the male section of rod 1. Also, for basing, a necessary and sufficient condition may be the presence of two holes on each side (opposite sides) of the female section of rod 2, and, accordingly, the presence of mating holes in the male section of rod 1.With each of the indicated basing options, the excess degrees of freedom of the connected part relative to the base part in their connection are removed.

[0043] For any connection. The connection of rod 1 and rod 2 is achieved by placing the male section of rod 1 within the cavity of rod 2, in its female section. The opening in rod 2, which allows the male section of rod 1 to enter the cavity of rod 2, may correspond to the cross-sectional shape of rod 1. For a solid rod 2, the cavity may be a groove or recess that allows a section of rod 1 to be accommodated therein. For a hollow rod 2, such as a pipe, the pipe cavity itself is a cavity that allows a section of rod 1 to be accommodated therein. As noted above, rod 1 and rod 2 may be connected at an angle of 30-150 degrees. For a solid rod 2, when connected at an angle other than 90 degrees, the cavity has an increased size, namely, the width of the cavity must be increased by a size that ensures the possibility of placing a section of rod 1 in it.The dimensions (width) of the opening providing access for section 1 of rod to the cavity of rod 2 should also be increased. If the end section of rod 1 is positioned within the cavity of rod 2, this end section, namely its end face, may also be formed at an angle other than 90 degrees. This solution results in no reduction in the mating areas of rods 1 and 2. Accordingly, the opening providing access for section 1 of rod to the cavity of rod 2 may conform to a cross-sectional shape at an angle other than 90 degrees.

[0044] For hollow rod 2, when connected at an angle other than 90 degrees, the opening allowing access from rod 1 to the cavity of rod 2 can be enlarged. For any of the above options, the side walls of the opening can be angled accordingly to ensure a tighter connection between rods 1 and 2.

[0045] When rod 1 and rod 2 are connected at an angle of 90 degrees, the opening that allows a section of rod 1 to enter the cavity of rod 2 corresponds to the cross-sectional shape of rod 1.

[0046] Rod 1 is fastened to rod 2 by holes drilled in each of them and the fasteners used with them, such as screws, bolts, and nuts. The holes in rod 2 are located perpendicular to its longitudinal axis and perpendicular to the longitudinal axis of rod 1, while the corresponding holes in rod 1 are located perpendicular to its longitudinal axis, within its enclosing section.

[0047] As noted above, rod 1 may be either solid or hollow. It is possible for the male section of rod 1 to be hollow, while the rest of the section is solid. Depending on the material used, the male section of solid rod 1 may be formed with a blind hole or a through hole (with a blind or through cavity), for example, rectangular. This can be done, for example, using a cutting tool, including milling, turning, or sawing. Casting in the desired shape is also possible. In solid rod 2, the female section (cavity) can be formed in a similar manner. In hollow rod 2, the female section can also be formed using a cutting tool. In the case of making the rod 1 solid, in its covered section, fastening holes can be made, through holes, blind holes, and also simultaneously through holes and blind holes.Through holes can be either threaded or unthreaded. Blind holes are threaded. Since rod 1 has a convex quadrilateral cross-section, meaning it is a quadrilateral, each side can be used to drill one or more holes.

[0048] Rod 1 may have a quadrilateral cross-section with all sides equal, such as a square cross-section. In this case, any of its opposite, parallel sides, in pairs, may be connected to the mating internal surfaces of the cavity or groove of rod 2. The corners of rod 1 and rod 2 may be rounded or slightly modified in the same manner.

[0049] Thus, the enclosed section of rod 1 may have at least one fastening hole on each side. Each opposite hole may be either on the same axis as it or on another parallel axis. Thus, each of the four sides of the enclosed section may have at least one fastening hole, and it may be on its own axis. Accordingly, the presence of holes with distances between their axes, possibly with a certain pitch, allows for a change in the position of rod 1 relative to rod 2. To attach rod 1 to rod 2, one fastening hole, for example, a threaded hole, and one fastening element (article) used with it, for example, a screw, are sufficient. To ensure the basing of rod 1 relative to rod 2 in the absence of degrees of freedom, the conditions specified above should be taken into account in the design, designed to allow a change in the position of rod 1 relative to rod 2.If increased adjustment capabilities are required, each of the four sides of the encompassed section of rod 1 can be used. Accordingly, the adjustment capability can be implemented, for example, in the form of four positions of rod 1 relative to rod 2. Even small interaxial distances, for example, from 0.5 to 1.5 mm, allow for adjustment of the connection unit during assembly of the main structure, for example, related to a furniture frame and / or similar structure. Adjustment capability (the ability to change the position of rod 1 relative to rod 2) can also be realized by making mating fastening holes in rod 2 not round, corresponding to fasteners (screws), but oblong (in the form of grooves), providing for radial movement of the fastener. Such holes provide the ability to change the distance between rods 1 and 2 and the ability to continuously adjust the angle.For example, each longitudinal groove can be between 5 and 40 mm long, allowing rod 1 to be fixed relative to rod 2 over a fairly wide range of positions. Several pairs of holes can also be provided for discrete adjustment, for example, for angles of 30, 45, 60, 75, 90, 105, 120, 135, or 150 degrees.

[0050] Other Possibilities for Changing the Position of One Rod Relative to Another. The geometry and shape of the fastening holes (each of them) can provide the ability to change the position of one rod relative to another. Such holes can be located either in each rod or in just one of them. Each non-threaded hole can have a shape: oblong straight, oblong arcuate, oval, round, polygonal, including rectangular, square, or any other that allows the use of a fastener (fastener, screw, bolt, etc.) while allowing radial movement for it (or its rod). Each such hole in the enclosing rod (in a rod with a cavity) must ensure that the head of the fastener (or the washer used with it) cannot be missed while maintaining clamping force.Adjustment can allow for the position of the female rod to be changed along the axis of the male rod, transversely to the axis of the male rod, or at a non-right angle to its axis. Thus, by utilizing the geometry of the mounting holes, the connection assembly can be designed to allow for the adjustment of the relative positions of the rods.

[0051] Fasteners for connecting rods 1 and 2.

[0052] Fasteners (fasteners)—parts used to form a detachable connection—can be used to connect rods (parts) 1 and 2. These can include: screws, bolts, self-tapping screws, wood screws, rivets, dowels, washers, studs, nuts, embedded parts with threaded holes, rivet nuts, etc. For example, in accordance with GOST 27017-86, for example, metal, steel, alloy steel, non-ferrous metals and their alloys. To simplify assembly, set screws and bolts can be used. Also possible for connections and fastenings: threaded bushings with flanges, countersunk bushings, screws with various types of heads, including round ones, for example, according to ISO 4762, spring washers, self-locking nuts, etc.

[0053] For furniture constructions, fasteners of strength classes 3.6, 4.6, 4.8, 5.6, 5.8 can be used. The strength class determines the mechanical properties of steel fasteners.

[0054] To connect wooden parts into a single structure, furniture mortise fittings according to DIN 1624, classification M4, M6, M8, M10 can be used.

[0055] If holes are made on opposite sides of the enclosing section of rod 2, coaxial fasteners (parts) may be bolts and nuts. To connect rod 2 to rod 1, each hole (blind and / or through) in rod 1 may be threaded. For this purpose, for example, if rod 1 is made of pipe (or a section of pipe), each hole may have a local thickening for threading, or may be equipped with a rivet nut or threaded embedded part. Such embedded parts may be metal elements (round, strip, or angle) that are installed (embedded) in the pipe prior to assembly of the utility model.

[0056] Accordingly, screws and bolts are used as fasteners with threaded holes. When threaded holes are in the male rod, to ensure the relative position of the rods can be adjusted, each hole in the female rod will be designed to allow radial movement of the fastener (screw, bolt, etc.).

[0057] In this case, threaded products used in threaded connections (screws, bolts, nuts, in rod 1 - rivet nuts) are preferred for use.

[0058] Examples of calculating a connection node made of steel pipes, each of which has a rectangular cross-section.

[0059] Option 1. Straight threaded holes. Standard ISO 965 taps can be used to cut threads directly into the pipe wall.

[0060] Thread depth calculation:

[0061] - the available thread depth is limited by the pipe wall thickness: Leng=t;

[0062] - number of full turns: N=t / P (where P is the thread pitch);

[0063] - minimum required number of turns:

[0064] - formula for calculating the unwinding force

[0065] - Fpullout=0.5 × π × d3 × t × σu,

[0066] where d3 is the diameter of the dividing cylinder according to ISO 965, t is the pipe wall thickness (mm), σu is the yield strength of the material (510 MPa for S355). Examples of calculated values ​​for S355.

[0067]

[0068] Limitations of option 1:

[0069] - applicable when t ≥1.5mm (minimum M5 or M6);

[0070] - technological simplicity of fastening;

[0071] - the possibility of using standard, widely used equipment;

[0072] - To prevent loosening due to vibration, additional measures are required, such as fixing compounds, spring washers, etc.

[0073] Option 2. Rivet nuts. Installed on one side using a specially designed tool.

[0074] Characteristics of rivet nuts (ISO 13849).

[0075]

[0076] Effects when using option 2:

[0077] - works at t=0.5-3.0 mm (universal);

[0078] - installation on one side only (“blind” connection);

[0079] - vibration resistance;

[0080] - can be removed and reinstalled multiple times;

[0081] - technologically more complex;

[0082] - Requires a dedicated tool for installation.

[0083] Comparison of pull-out strength: threaded holes and rivet nuts for different wall thicknesses is shown in the graph, Fig. 5. The inclined lines are threaded holes, the lower line is M3, the lines above are M4, M5, M6, respectively.

[0084] Dotted lines are rivet nuts, the bottom line is M3, the lines above are M4, M5, M6 respectively.

[0085] Horizontally - material thickness, mm (pipe walls), vertically - force kN (moment).

[0086] The graph shows that:

[0087] - the threaded thread has a linear dependence of the bearing capacity on the thickness of the material (F ∝ t);

[0088] - rivet ("blind") nuts have a constant load-bearing capacity regardless of the thickness of the material;

[0089] - intersection point: at a thickness of t=1.5 mm, both technical solutions achieve the same characteristics.

[0090] Conclusion: for t<1.5 mm, rivet nuts provide 50-150% more strength; for t>1.5 mm, threads are technologically simpler. Examples of selection for various pipes of various sizes. Optimal screw (bolt) configuration parameters for perpendicular connections of rectangular pipes.

[0091]

[0092] Possible applications: from light fittings to industrial structures.

[0093] Recommendations

[0094] 1. At t=0.5-1.0 mm (thin-walled pipes) -

[0095] Option 2 (rivet nuts M3-M5), threaded thread is not desirable (too few turns).

[0096] 2. At t=1.5 mm,

[0097] Option 1 (M5 threaded): F=10.8 kN - acceptable;

[0098] Option 2 (M5 rivet nuts): F=11.5 kN - recommended;

[0099] Selection depending on production volume and requirements.

[0100] 3. For t=2-3 mm (reinforced pipes): Option 1 (thread M6-M8) is recommended.

[0101] Mounting torque (Tmounting).

[0102] For threaded cutting (option 1): Recommended torque = (0.5…0.7) × Tmax, where Tmax is the maximum loosening torque.

[0103] Examples:

[0104] M5 at t=1.5 mm: Tinstallation=20-25 Nm at Tmax ≈38 Nm;

[0105] M6 at t=2.0 mm: Tinstallation=40-50 Nm at Tmax ≈ 72 Nm.

[0106] For rivet nuts (option 2).

[0107] M5 nut: Tmounting=5-7 Nm (max 7.5 Nm);

[0108] M6 nut: Tmounting=8-11 Nm (max 11.5 Nm).

[0109] Excessive torque causes the nut to loosen.

[0110] For most cases, M5 threaded bolt, with t=1.5-2.0mm and 2 screws per unit, can be suitable, providing a load-bearing capacity of 10-15kN and a safety factor of K≥3 for typical furniture loads.

[0111] Additionally for the rod connection unit, the fastening holes of which are provided with rivet nuts.

[0112] Specifically, two holes are drilled on each side of the enclosing section of rod 2, and there are also two counter-holes drilled in rod 1. Each counter-hole is equipped with a rivet nut, and the fasteners used with them are screws.

[0113] This design provides a balance between strength and costs associated with technological complexities.

[0114] Pipe wall thickness t=0.5-1.0 mm (thin-walled pipes).

[0115] Rivet nut: M3-M4, the number of nuts is 4, respectively, 4 screws;

[0116] Distances: e=12-20mm, s=30-40mm;

[0117] Bearing capacity: 13.6-15.6kN;

[0118] For chairs, stools, light shelves and other furniture.

[0119] Pipe wall thickness t=1.0-2.0 mm.

[0120] Rivet nut: M5, the number of nuts is 4, respectively 4 screws;

[0121] Distances: e=20-25mm, s=40-55mm;

[0122] Bearing capacity: 46kN;

[0123] Safety factor: K=7-8 (for typical furniture products);

[0124] For shelving, table frames, cabinets, and other similar furniture,

[0125] where e is the distance from the edge, s is the distance between the axes of the screws - are given as an example and depend on the size of the pipe used.

[0126] Pipe wall thickness t=2.0 mm.

[0127] Rivet nut: M6, the number of nuts is 4, respectively, 4 screws;

[0128] Load-bearing capacity: 66kN.

[0129] Pipe wall thickness t=2.5-3.0 mm.

[0130] Rivet nut: M8, the number of nuts is 4, respectively 4 screws;

[0131] Load-bearing capacity: 108kN.

[0132] The safety factor for the above connections with M6-M8: K=9-14.4. To increase strength, it is possible to increase the number of fasteners, for example, more than two on each side.

[0133] Riveted joints. Conventionally, a riveted joint is considered permanent. The design of the joint allows for the removal of installed rivets, for example, using a cutting tool (drill, chisel), which suggests that the riveted joint cannot be damaged. In other words, the utility model is designed to be assembled and disassembled (allowing for multiple assembly and disassembly). The riveted joint provides high resistance to impact and vibration loads. The use of a riveted joint in the utility model is also possible for design and technological reasons: changes in the metal structure are excluded; dissimilar, difficult-to-weld, and non-weldable materials can be joined; the possibility of fatigue crack propagation from one part to another is prevented in advance.Depending on the nature of the load applied to a riveted joint, the joint may have joints subject to transverse loads perpendicular to the rivet axis. Depending on the requirements for the utility model and its surfaces, rivets with various head types may be used: flat, semicircular, countersunk, and semi-countersunk. Rivets made of steel, aluminum, and other materials, with various coatings, such as polymer coatings, may also be used.

[0134] Rivets and installation methods. Rivets are inserted into pre-drilled holes in the components (in the sheet stack formed after aligning / joining the assembly components in the required configuration) in the connecting assembly. These holes are present in rods 1 and 2. Riveting is then performed using a specially designed tool in the second closing head. If necessary, to increase rivet ductility, preheating to high temperatures (e.g., with gas or high-frequency current) is possible before installation. During riveting, the sheet stack is compressed (the beam and the column tube are pressed together), and due to the transverse elastic-plastic deformation of the rivet shank, the initial gap between the shank and the hole walls is filled, which may result in interference.

[0135] Depending on the diameter of the rivet, the diameter of the hole for the rivet d is selected according to the standard отв- For cold riveting it is recommended:

[0136] d oтв =d3+0.05d3, where d3 is the diameter of the rivet being installed.

[0137] Hot riveting rivets, cold riveting rivets, rod rivets, tubular and semi-tubular rivets, and pull-out rivets can be used.

[0138] The utility model makes it possible to: achieve a backlash-free (gap-free) connection due to the elastic deformation of the walls of the inserted rod 1; achieve the effect of compensating for manufacturing tolerances in the dimensions of the parts being connected; achieve the effect of increasing the vibration resistance of the threaded connection due to the creation of a spring-loaded effect. These effects can be achieved by introducing small cuts (slots) on the vertical walls of the end male section (in the case of such a design) of the inserted pipe (rod 1). Each vertical wall can have a cut. This solution transforms the end male section of rod 1 into a collet (spring-loaded) element. Another male section of rod 1 (not the end one) can be made similarly. For example, vertical walls with cuts, and a horizontal wall, also with a cut to ensure mobility (the possibility of deformation) for the vertical walls.

[0139] Achieved effects when assembling a node

[0140] Compensation for manufacturing errors (tolerances):

[0141] If the inserted pipe's cross-sectional area is slightly larger, or the inlet and / or cavity in the receiving pipe (in rod 2) is slightly smaller (by a fraction of a millimeter), the rigid pipe will simply not fit or will jam. The slits in the walls allow for a slight spring force during insertion (when connecting rod 1 to rod 2).

[0142] This significantly changes the manufacturing accuracy requirements for the connecting unit components. Assembly becomes smoother and easier.

[0143] Simplifying centering: When inserted, the cut walls act as guide springs, centering the inserted male (end or other) section of rod 1 relative to the outer tube (rod 2). This, in turn, helps the mounting screws fit into the threaded holes. Reduced stress and damage during assembly: This makes the contact elastic rather than rigid, reducing the risk of metal-to-metal "biting," scuffing, and damage to coatings such as paint.

[0144] Achieved effects in the assembled unit

[0145] Expanding effect (V-shaped wedge):

[0146] The cuts in the inner tube allow it to deform (expand or contract), pressing more tightly against the inner surfaces of the outer tube (to the inner surfaces of the cavity in rod 2).

[0147] Complete elimination of backlash (rattle):

[0148] In a standard rigid connection, there should always be a small gap between the outer pipe and the inner pipe. When assembled, this gap should allow for a slight amount of play. With slits, the enclosed section of the inner pipe acts like a spring, taking up this gap. The assembly becomes "monolithic," eliminating creaking and mutual movement of the assembly parts.

[0149] Increased vibration resistance of the connection:

[0150] The elasticity of the cut walls creates constant tension in the threaded connections (Grover washer effect). This reduces and eliminates the risk of spontaneous loosening due to vibration. Threaded sleeve rotation is reduced and eliminated.

[0151] Possible defects with cuts. Weakening of the section. For most types of furniture, this is not critical, but can be a drawback for heavy-duty industrial shelving.

[0152] To reduce these imperfections, each cut can be made with a hole at the end (like a keyhole). This relieves stress and prevents cracks in the material under repeated loads.

[0153] Possible slit designs. Length - from 10 to 30 mm; width - from 2 to 4 mm; a round hole with a diameter of 3-5 mm at the end of the slit; there may be more than one slit on each vertical wall. To strengthen the rod connection, it is possible to use additional fasteners (screws, bolts, etc.), as well as on the mating surfaces, the use of guide grooves, such as T-shaped, H-shaped, wave-shaped mating surfaces, the use of damping elements, such as gaskets, inserts, etc.

[0154] To increase the speed and accuracy of assembly of the joint, the male section of rod 1 can have a guide element(s), such as pins or projections, while the female section of rod 2 can be provided with fixing holes, cutouts, or recesses for these pins and projections. The holes and recesses can be fitted with bushings. This can be implemented more easily for a design in which the male section of rod 1 is the end. This solution also ensures that rod 1 and rod 2 are in a specific and strictly fixed relative position (base). This ensures automatic alignment and rapid assembly of the joint, as it allows the parts to instantly "snap" into the desired position during assembly without the need for precise adjustment with screws. Centering chamfers can also be used to simplify positioning.

[0155] Related, additional effects:

[0156] Self-centering effect: the protrusions (pins) automatically enter the recesses (sockets), determining the relative position of elements 1 and 2;

[0157] Reduced assembly time - no need to select the position of parts;

[0158] Increased repeatability - each protrusion (pin) corresponds to a strictly defined location, which eliminates errors during multiple assemblies.

[0159] Effects associated with fasteners (products)

[0160] Frictional connection effect - when tightening the screws, a frictional force is generated between the connected surfaces, which provides additional rigidity to the structure.

[0161] Pre-stress effect - tightening the screws creates pre-stress in the connection, which increases its resistance to dynamic loads.

[0162] The technological advantage of rivet nuts: using rivet nuts allows for the creation of threaded connections in thin-walled pipes, expanding design possibilities. They also allow for single-sided installation without rear access, allowing for quick installation without special preparation, and forming permanent, strong threads for fastening screws and bolts.

[0163] Effects associated with the fact that the connection and fastening of rods 1 and 2 to each other is carried out by means of holes made on one side of the enclosing section of rod 2, or made non-coaxially on each side of the enclosing section of rod 2, mating holes located in rod 1, fastening elements (products) used with all of these holes.

[0164] Using the fasteners described above significantly limits the degrees of freedom of the mechanical connection. Unlike a single fastener, a double fastener eliminates the possibility of rotation of rod 1 relative to rod 2 around the axis of the fastener (part). This creates an anti-rotational locking effect that is impossible to achieve with a single fastener.

[0165] Multiple fastening provides significantly higher connection rigidity compared to single fastening. Increasing the number of fasteners results in a more uniform load distribution and reduced stress concentration. Double fastening creates a distributed loading effect, with each fastener (part) bearing a portion of the total load. Two fasteners (parts) in a connection provide increased vibration resistance. Even if one fastener loosens, the second continues to provide fixation, creating a redundant effect and increasing structural reliability. Thus, increasing the number of fasteners (parts) in a connection from one to two creates qualitatively new structural properties.

[0166] Effects related to mechanical properties

[0167] Damping effect - the dismountable structure with multiple joints has the ability to absorb vibrations due to micro-movements in the joints. This damping effect reduces vibration transmission.

[0168] The effect of temperature deformation compensation - the presence of gaps in the joints allows for compensation for thermal expansion / contraction of materials when the ambient temperature changes.

[0169] Self-locking effect of threads - a self-locking effect appears in threaded connections, preventing spontaneous loosening of fasteners during vibrations.

[0170] Materials

[0171] Materials for the manufacture of the utility model can be ferrous and non-ferrous metals and their alloys, polymers, plastics, wood, composite materials, glass, materials with light transmission, etc. For example, the advantages of cast metal are: the monolithic structure eliminates weak points of welded joints, reducing the likelihood of fatigue failure, including during multiple assembly / disassembly cycles. For the manufacture of metal elements (rods), the following can be used: carbon structural steel 08PS. The strength and hardness of this steel are low, but the advantages of this steel are impact toughness and ductility, making it resistant to dynamic (impact) loads. Also steel 3, steel 5, and for operation in low temperatures steel 09G2S. Other materials can be carbon steels, low-alloy steels (such as 09G2S, St3SP), alloy steels (corrosion-resistant).Of the latter, austenitic steels, austenitic-ferritic steels (such as 08Kh21N6M2T, 08Kh22N6T, 08Kh18G8N2T), and austenitic-martensitic steels (such as 08Kh17N5M3, 07Kh16N6, 09Kh15N9Yu) are preferred. Corrosion-resistant steels and alloys, including stainless steels, can also be used. The utility model may utilize components made of different materials. For example, rod 1 and rod 2 could be made of polymer or wood, or some other combination.

[0172] Variants of the utility model, dimensions

[0173] The rod (2) is made of a pipe with a rectangular cross-section of (10-200) x (10-200) mm, the wall thickness of the pipe is 0.5…5 mm,

[0174] Rod (1) is made of a rectangular pipe with a cross-section of (10-200) x (10-200) mm, pipe wall thickness of 0.5...5 mm, screws from M3 to M12. Solid rods 1 and 2 can be selected similarly.

[0175] Corrosion protection. Available protective coatings include galvanizing, phosphating, passivation, and oxidation. Hot-dip galvanizing is achieved by dipping the part in molten zinc at 450-480°C, creating a coating layer of 50-150 µm. Low-carbon and alloy steels require protective coatings. Aluminum and titanium alloys form passive oxide films that protect the substrate from corrosion; Ti-6Al-4V's TiO2 film ensures long-term stability in various environments.

[0176] Protective coatings. The surfaces of metal elements may have a protective and decorative coating, for example, at least class 3 according to GOST 9.032-74, GOST 9.410-88 and at least class 2 for galvanic coating according to GOST 9.104-79, GOST 9.103-78. To protect against corrosion and aging, the connecting assembly may have the following coatings: protective, protective and decorative, electrical insulating, or abrasion-resistant.

[0177] Powder materials for coating

[0178]

[0179]

[0180] Materials used as primers

[0181]

Claims

1. A rod connection unit characterized in that it is made by means of a rod (1) and a rod (2) connected to it at an angle of 30-150 degrees, each rod (1, 2) is made with a cross-section in the form of a convex quadrangle, the opposite sides of which are parallel, the adjacent sides are perpendicular, the connection of the rod (1) and the rod (2) is carried out by means of the fact that the covered section of the rod (1) is placed in the cavity of the covering section of the rod (2), wherein the fastening of the rod (2) to the rod (1) is carried out by means of holes made in each of them and fasteners used with them, wherein the holes in the rod (2) and the corresponding holes in the rod (1) with their axes are located perpendicular to the longitudinal axis of the rod (1), the location and number of said holes, as well as fasteners used with these holes, ensures the basing rod (1) relative to rod (2) in the absence of degrees of freedom.

2. A rod connection unit according to paragraph 1, characterized in that it is made by means of a rod (1) and a rod (2) connected to it at an angle of 90 degrees, the opening providing access for a section of the rod (1) into the cavity of the rod (2) corresponds to the shape of the cross-section of the rod (1).

3. A rod connection unit according to any one of paragraphs 1, 2, characterized in that the fastening of the rod (2) to the rod (1) is carried out by means of holes made on each side of the enclosing section of the rod (2), mating holes made in the rod (1), fasteners used with all these holes, the holes made on opposite sides of the enclosing section of the rod (2) are coaxial in pairs.

4. A rod connection unit according to paragraph 3, characterized in that on each side of the enclosing section of the rod (2) there are two openings, and there are also two mating openings made in the rod (1).

5. A rod connection unit according to any one of paragraphs 1-4, characterized in that the rod (1) is made of a pipe, the rod (2) is made of a pipe.

6. A rod connection unit according to paragraph 5, characterized in that the rod (1) is made from a pipe of rectangular cross-section, and the rod (2) is made from a pipe of rectangular cross-section.

7. The rod connection unit according to item 6, characterized in that the rod (2) is made from a pipe with a rectangular cross-section of (10-200) x (10-200) mm, the pipe wall thickness is 0.5-5 mm, the rod (1) is made from a pipe with a rectangular cross-section of (10-200) x (10-200) mm, the pipe wall thickness is 0.5-5 mm.

8. A rod connection unit according to any one of paragraphs 1-7, characterized in that the mating holes made in the rod (1) are threaded, and the fasteners used with them are threaded.

9. A rod connection unit according to paragraph 8, characterized in that the mating holes made in the rod (1) are provided with rivet nuts, and the fasteners are screws.

10. A rod connection unit according to any one of paragraphs 1-9, characterized in that the covered section of the rod (1) is designed with the possibility of elastic deformation, ensuring the possibility of a backlash-free connection of the rod (1) with the rod (2).

11. A rod connection unit according to any of paragraphs 1-10, characterized in that the rods (1, 2) are made of structural steel, and the fasteners are made of structural steel.

12. A rod connection unit according to paragraph 11, characterized in that it has a protective coating.

13. The rod connection unit according to paragraph 12, characterized in that polyester powder paint is used as a protective coating.

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