The suspension of the supporting cable and its tension is done in two steps. First, the cable is pulled along the length of the wiring and one end is secured to the end anchor structure, the tension bolt of which is previously loosened. The second free end of the cable is measured according to the actual length of the liner, taking into account the length of the cable required for sealing loops and installation tensioning devices and compensation of the boom sag, and attach it to a pre-weakened special tensioning device, if necessary. Then they create a preparatory tension of the supporting cable together with a tensioning device, which is put on the 2nd end anchor hook. The tension of the supporting cable, depending on its length, is carried out manually at small gaps, and with the use of blocks, pulleys or winches at large gaps.
As already indicated, the cable tension should be created until the calculated sag is obtained, but with a force not exceeding the tension force permissible for a given load-bearing cable. Monitoring the correct tension of the supporting cable is carried out by a dynamometer, connected alternately with the cable of the pulley block or block, with the help of which the tension of the cable is created, or by measuring the sag. The final tension and adjustment of the supporting cable is created by tightening previously loosened tension devices. It is recommended to carry out work on hanging and tensioning load-bearing cables at an ambient temperature of at least -20 degrees Celsius.
To unload the supporting cable and its end fastenings and reduce the sag in the cable runs, various unloading devices are used in the form of additional vertical, longitudinal and transverse auxiliary wire hangers and guy wires.
To make the cable wiring more immobile and to prevent lateral swings, side braces are installed.
Vertical wire hangers are installed approximately every 3 -12 m, placing them in the locations of branches from wires and cables, installation and suspension of branch boxes, branches and lighting fixtures.
Vertical wire hangers are made from metal wire with a diameter of 2-6 mm for power lines that are heavier in weight and with a diameter of 2-3 mm for lighter-weight lighting lines.
Longitudinal lateral and transverse guys are made of metal wire with a diameter of 2 - 6 mm.
For string electrical wiring, unlike cable wiring, the supporting string in a tense state is attached tightly to floors, trusses, supports, walls and protruding parts of walls, columns and others construction grounds using different methods.
Figure 12.7 – End fastening structures of cable wiring and methods of their installation:
c - tension bolt with hook, b - cable tension anchor, "- anchors for end fastening wire strings secured with studs, pins, dowels, and electric welding, d - cable anchors for end fastening of factory-made steel cables, e - structures for fastening cables and wires to metal trusses made of profile steel and T-beams, f - structure for fastening parallel load-bearing structures cables
As load-bearing elements, hangers of guy wires are used: steel rope (cable with a diameter of 1.95 - 6.5 mm, galvanized steel wire with a diameter of 2.5 - 6 mm, round hot-rolled wire (rod) with a diameter of 5 - 8 mm, bare galvanized steel wire with a diameter of 6, 8 and 7.5 mm, twisted from ordinary steel or copper-plated steel wires, a rope that serves simultaneously as a support cable and a neutral wire.
During the process of procurement work, hangers and branch clamps for aluminum and copper wires and boxes for wires of the ANRG brand, make the necessary connections and descents to connect the wiring to the supply line.
Figure 12.8 – Products and parts for installation of cable wiring:
a - box for branching from main lines, 6 - cross-shaped and tee compression, c - ram compression, d - suspension with plastic clips, e - steel suspensions, e - strip with a buckle and a strip-buckle for banding wires and cables; 1 - strip for fastening the branch box, 2 - box body, 3 - clamp, 4 - dies, 5 - suspension brackets, 6 - eyelet for fixing the lamp
For branches from main lines made with three- and four-core wires of the APT brand, a branch box is used (Figure 12.8, a), which can be of three types: 0.2 - for lighting networks with a core cross-section of main wires of 4-10 mm2 and branch wires of 1-2.5 mm2; C2 - for lighting and power networks with a cross-section of main and branch wires of 4-10 mm2; SZ - for power networks with a cross-section of main wires of 16-35 mm2 and branch wires of 4-10 mm2.
Branches from main aluminum and copper wires are made using cross-shaped and tee clamps (Figure 12.8, b). For branches of wires with a cross-section of 6, 10 and 16 mm2 from the wires of main lines with a cross-section of 35 and 50 mm2, die clamps are used (Figure 12.8, c).
To hang four insulated wires with a cross-section of up to 6 mm2 and lamps from a cable with a diameter of 4-7 mm, a plastic hanger U930-U934 is used (Figure 12.8, d), and for a cable on a cable with a diameter of up to 10 mm, a steel hanger U954-U956 is used (Figure 12.8, d). d).
Banding of wires and cables is performed with a steel strip with a buckle or a buckle strip (Figure 12.8, e).
3 Methods of fastening cables
At the second stage of installation, the prepared sections and assemblies of cable wiring are assembled into a common strand and suspended on tension devices and supporting structures installed at the first stage of installation.
The prepared cable wiring delivered to the installation site is unwound and straightened, while simultaneously checking its condition and completeness. If the wiring is added in the form of separate sections and nodes, they are assembled into cable strands, and then the finished wiring is suspended in place. The assembly and suspension of cable wiring is shown schematically in Figure 3.
To assemble and suspend electrical cable wiring, one end of the supporting cable (right in Figure 3) is terminated with loop 1 and thrown onto a temporary right anchor hook 2, installed at a height of 1.5 m. The second temporary anchor hook 2, located on the opposite wall of the room, is thrown a loop of one end of the pulley 8, and a wedge clamp 5 is attached to the free end of the pulley, which grips the cable at some distance from the end loop of the supporting cable. In this case, the free (in Figure 3 left) end of the cable and the tension coupling 9 mounted on it will be in a suspended position. The supporting cable suspended between temporary anchors, together with the electrical wiring elements attached to it, is pulled with a pulley until the required sag is formed. The tension value of the supporting cable is controlled by a dynamometer located between the pulley and the wedge clamp.
Figure 3 – Scheme of assembly and suspension of cable wiring at the installation site: 1 and 1" - end loops on the supporting cable, 2 and 2" - temporary and permanent anchors, 3 - inventory stands, 4 - string of cable wiring, 5 - wedge clamp, 6 - auxiliary section of cable, 7 - free end of the supporting cable, 8 - pulley block, 9 - tension coupling, 10 - dynamometer, 11 - vertical wire hangers
The forces when tensioning the cable of ATRG wires should not exceed: 100 kgf for cable wires with a core cross-section of 4-10 mm2; 500 kgf - for wires with a core cross-section of 16-35 mm2.
After tensioning the electrical cable wiring is completed, the free end of the supporting cable with the tensioning device is put on the left anchor hook 2, the pulley 8 is loosened and removed from the hook. Next, inventory stands 3 are installed under the cable, supporting the electrical wiring at a height convenient for work.
At the final stage of installation, the lamp housings are suspended and secured on a cable, but without glass parts (reflectors, glass caps, etc.), and the height of the wiring suspension is adjusted (by changing the length of the pendants 11). anchor fastenings, and also perform a number of other installation operations.
The assembled string of electrical wiring is lifted, connected to anchor fasteners and a tensioning device, tensioned using tensioning devices, the vertical wire hangers are finally adjusted and secured, lamps are installed in the lamps and reflectors and caps are secured in the lamp bodies, the correctness is checked relative position all electrical wiring parts.
In accordance with the requirements of the PUE, elements of cable wiring (supporting cable, lamp housings, cable sheaths, etc.) must be grounded. To ground the cable wiring, its fastening structures and the supporting cable are connected to the grounding busbars using flexible jumpers made of a steel cable with a diameter of at least 5 mm or stranded copper wire with a cross section of at least 2.5 mm2.
If a support cable is used as a neutral or grounding wire, the cross-section of the jumper must correspond to the calculated cross-section of the neutral or grounding wire.
Grounding is done like this. Cut a piece of cable or flexible copper wire of the required length and required cross-section for use as a grounding jumper. A steel sleeve or flag is welded to one end of the jumper, which, in turn, is welded to the grounding bus. The opposite free end of the jumper is connected to support cable using a bolt clamp.
Metal support and cable structures located on the supporting cable are grounded by securely connecting them to the supporting cable.
Cable electrical wiring made with ATRG wires is grounded, connecting the section of the carrier millet freed from insulation with the body of the branch box, inside of which there is special device.
In lighting installations with a solidly grounded neutral, the neutral wire and lamp housings are also connected to the anchor device of Special boxes or to the neutral wire in ordinary boxes. In this case, the electrical wiring together with the supporting cable is grounded through the neutral wire of the lighting network.
Metal housings of lamps in cable wiring with open gasket wires are grounded using separate grounding insulated copper conductors with a cross-section of at least 1.5 mm2. The ends of the grounding conductors are connected to the lamp housings under the grounding screws, and to the neutral wire or to the supporting cable (if one is used as a neutral wire) - by soldering or mechanical compression.
In cable wiring with open laying of protected wires and cables, grounding of lamps is performed using an additional core included in the design of the cable and wire. In these cases, the grounding conductor is connected not to the neutral wire in the branch box, but to the luminaire body - inside or outside it, depending on the design of the luminaires.
Upon completion of installation of cable wiring:
- measure the insulation resistance of the wires and cables of cable wiring with a 1000 V megger with the fuse links removed and the lamps in the lighting circuits unscrewed, but with switches, sockets and group panels connected; insulation resistance must be at least 0.5 MOhm;
- determine the correct phasing of cable wiring and branches from it; the phases must match;
- check the condition of the insulation of the current-carrying conductors of wires and cables in relation to the supporting cable, as well as the continuity of the grounding circuit: cable - branch box - grounding conductor.
If the results of the checks are satisfactory, the cable wiring is transferred for operation.
The wedge clamp for the cable is special device, the purpose of which is to firmly connect the cables to each other. It can also be used to make a loop at the end of the same cables. But what else do you need to know about these elements?
Why is this detail in construction?
Typically, such devices are used where work is carried out under heavy loads, so only high-strength and high-quality metals are always used for the manufacture of clamps. Manufacturers produce these devices strictly in accordance with standards. The design of the clamps is very simple. They consist of two hex nuts and a steel bow. Professionals recommend installing at least three clamps on one cable; this is enough for safety and reliability of fastening. If the load is higher than the clamps you have chosen can withstand, then you should take a different type of this clamp, and not increase the number.
For production, only high-quality and is always used. This is necessary to ensure a reliable connection at both ends of the elements. For greater reliability and strength, the clamps are often additionally coated with another protective layer. For these purposes, galvanic galvanization is used. The advantage is that with its help the device is provided with maximum resistance to external influences environment. It also provides excellent protection against corrosion.
Although constructive solution This device is simple, but you still need to read the instructions before using it. Any tool or device has its own nuances that must be taken into account in the work. If the clamp is installed incorrectly, the element may simply break off. The end of the cable is inserted into the arc and secured inside using a special lock, in this case hex nuts. The nuts are twisted in different directions, and the cable will be between them. When fully twisted, the ends should be tightly pressed together.
Steel cable clamp - classification
Clamps come in different types. They are divided according to purpose, material used and design. You can also formally designate different lengths; the most popular cable clamp is 3 mm, 5 mm in diameter, but in special cases sizes up to 40 mm are used. Each species also has different subspecies. Clamps, which are divided according to purpose, are ordinary and reinforced, and according to the material used - steel and copper; an aluminum cable clamp is also popular; a galvanized steel version is used in particularly harsh operating conditions. Clamps, which are divided by design, are flat, arc-shaped, single and double.
Regular clamps are the most common. Typically, galvanized steel class 2 is used for their manufacture. appearance These clamps resemble closed loops at the base that have two strong bolts. This type of product is for household use and is not intended for heavy loads. The reinforced version speaks for itself, its design is more thoroughly worked out, the shutter mechanisms are reinforced, and therefore the scope of their application may be more responsible.
Flat types of clamps are often made of high-strength carbon steel. The surface of these devices is galvanized. Their diameter can range from 2 to 40 mm. In shape, such clamps resemble a pair of plates that are connected to each other with a bolt and nut. They are typically used for splicing steel cables or other standing rigging. They are also quite suitable for creating loops at the end of the brace. Professionals recommend installing at least two clamps on one connection.
Flat clamps can also be classified as single or double. The main difference is the number of bolts available. Single clamps are fastened with one bolt, and double clamps are fastened with two bolts. In terms of application, such clamps are not particularly different.
Arc-shaped clamps are made of a cylinder that is bent in an arc, and fastening occurs using two bolts that are located at the ends. Devices of this type are most often used for connecting metal cables, but it is quite possible to use them for making loops. This type of clamps is more industrial; they are designed for heavy loads. A typical standard arc clamp can withstand a load of about 97 kilograms.
Specialized and wedge clamps - what are their features?
Many construction works cannot be done without a strong clamp. Construction has always been characterized by the presence large quantity operations. You definitely need to lift something up, pull a load, and in this case it’s Construction Materials, you often have to fix various objects. For such work you need strong spring-loaded clamps. Not only do they allow you to connect the cables, but you can also attach a load to them. Such devices are not very different from standard clamps.
In addition to the usual metal arc, they have a pair of levers that are equipped with movable brackets. This design solution helps ensure a highly durable and durable connection. With its help you can securely fasten any object to the cable different thicknesses. IN Lately Wedge clamps are the most popular among specialists. This is an excellent connecting element for copper and aluminum wires, the cross-section of which can range from 35 to 100 square millimeters. Only this type of clamp is good for connecting steel-aluminum devices. Such devices consist of a body and a wedge, which is wear-resistant. Forged cast iron steel is used to make the body, and the wedge itself can be made of bronze or various aluminum alloys.
If it is necessary to install aluminum or steel-aluminum wires in bolted clamps, where the cross-sections are very large, then it is necessary to use special gaskets that are made of soft aluminum tape. The use of such an addition in work will give the mount the greatest mechanical strength. It is important to remember that after installation, such clamps must be tightened again ten days later.. The lift should be done like this. The first step is to press the hinge part of the aluminum housing, then you need to insert a steel anchor, and then the aluminum housing is inserted again using a steel mechanism.
How to make cable clamps with your own hands?
Cable clamps are used in many industries. There is no industry where they would not find application. But often ordinary household work cannot be done without such a small device. Car owners especially need them. A metal tube is required large diameter, a couple of metal plates and several bolts and nuts. The metal tube must be bent into an arc. The diameter of the pipe must be such that the cable that is planned to be used can fit into it. The cable must be inserted into the hole in the pipe until the end appears outside.
Then the end must be pulled out of the pipe to a distance of 10-15 cm, then the end of the cable and the cable itself will need to be covered with plates from below and above, and the plates must be tightly connected to each other using strong bolts. This device is well suited for making loops. If you need to connect two cables to each other, then you need to choose a tube with a larger diameter. It must be taken into account that two cables need to be inserted into one hole, but only in different directions. The plates are also selected taking into account the diameter of the cables. Such a clamp will always come in handy in household chores, just keep in mind that it is not suitable for heavy loads, but it is quite possible to try to use it as a tug.
If you ask the question what kind of lanyard device this is, few will answer it right away, although such a device has been known and actively used for decades. In many situations, there is a need to tighten ropes, chains, cables or other rigging, which must be done to more securely fix the guy wires. It is not always possible to achieve such a stretch using only your physical strength. It is to solve this problem that lanyards are designed, which we will talk about in this article.
What is a lanyard?
With the help of such a simple, but very convenient and reliable device as a lanyard, the performance requirements of which are regulated by the standards DIN 1748, DIN 1480 and GOST 9690-71, tension is ensured and they are kept in a tense state for a long period of time.
Lanyards used to be called differently: PTR-7-1, and the numbers in their designation varied depending on the model of the device and its technical characteristics. The numbers in the designation, in particular, characterize the magnitude of the destructive load (in tons-force) that a specific model of such a device can withstand. Devices for tensioning cables used earlier did not have such a wide variety of heads as is implemented in modern lanyards. Almost all models of such devices had heads made in the form of oblong loops at their ends, to which steel cables were attached. A little later, the magnitude of the breaking load of a particular lanyard began to be measured in kN. For example, if you decipher the name of the T-30-01 model, it will become clear that such a lanyard can successfully withstand a load of 30 kN, which corresponds to 3 tons-force.
Important characteristics of lanyards
To ensure that lanyards do not become deformed or destroyed during operation, it is necessary to take a very responsible approach to their selection. In addition, one should take into account both the dimensions of such devices and their features. geometric shape so that they are able to perform the tasks assigned to them. There are special tables that every seller should have: using them you can compare the marking of the lanyard model with its technical characteristics, size and shape. Both the characteristics, dimensions and type of such devices are specified by a number of international and domestic standards: DIN 1478, DIN 1480, GOST 9690-71, etc.
An important parameter of any device for tensioning steel cables is the thread diameter, and it is not necessary that both screws of such a device will have the same thread. Modern industry produces lanyards with different thread parameters: M5 (“baby”), M8, M10, M12, M16, M20, etc. But you will not find thread parameters in the designation, for example, of a lanyard model T-10-01, T- 30-01, etc. It is very convenient that such marking allows you to accurately determine which load is critical for these devices. It is the first digit in such designations that indicates that the lanyard can withstand a certain level of load, expressed in kN. More detailed information all characteristics of a particular model of such a device, including its exact drawing, can be found in the corresponding GOST.
Most steel braces and, accordingly, devices for tensioning them are used in conditions open air where they are exposed negative impact high humidity and temperature changes. To eliminate the harmful effects of such factors, lanyards must be reliably protected, which is ensured by their zinc coating or treatment paint and varnish materials. Thanks to such protection methods, such devices can be successfully operated for decades.
Lanyards according to DIN 1480 standard
Lanyards produced according to the DIN 1480 standard, if you understand their design, are a fairly simple device. The basis of their design is the body, which can be made in the form of a cylinder or an oblong ring. On both sides of the case there are threaded holes into which the working elements of such a device are screwed. These elements, depending on need, can have heads in the form of rings, hooks or forks. It is to the ends that the steel cable is attached, the tension of which must be ensured. What is important is that the working elements are screwed into the housing holes in different directions.
The lanyard bodies, made in the form of a cylinder, can have different design. So, it can be an open or closed cylinder, which is used in cases where it is necessary to protect threaded connections from harmful influence external factors: high humidity, dust and dirt. Cylindrical turnbuckles open type(even if you look at their photos) allow you to see how the threaded ends of the working elements converge when they are tightened.
It is no coincidence that lanyard heads are so diverse. Moreover, in one such device, heads of both the same and different types. For example, in practice you can often find devices for tensioning cables and ropes with fork-fork, hook-hook, ring-hook heads, etc. Such heads are selected depending on the design of the counter fastener: end steel rope or cable. Thus, a lanyard with a fork head is used to tension ropes, at the end of which a loop can be formed that fits tightly (tightly) between the legs of such a fork.
Chain type lanyard - ratchet
If the head of the tensioning device has the shape of a hook, then, accordingly, the tensioned cables or ropes must end in rings or other elements that will not slip out of engagement with the hook when a tension force is applied to them. If a lanyard with a ring-shaped head is used, the ropes and cables must end with hooks, which also must not slip out of gear.
A separate category consists of chain-type lanyards, which have a ratchet in their design. Such a device is often also called a ratchet, and it is used in cases where it is necessary to bring together and tension elements that are located at a considerable distance from each other. The area of use of such models is quite narrow, which is explained by their limitations in the degree of distance of the tensioned elements from each other. In addition, the design of such lanyards is quite bulky and includes a handle, which does not make it possible to use them in places with very limited free space.
Rope lanyard is a device that is widely used for installation, construction and rigging work. Thanks to this intermediate link, the tension of cables, ropes and cables can be easily adjusted. You are probably familiar with it, but you didn’t know its wonderful name!
What is this intricate tool used for?
Since the cargo lanyard has a special design, this allows it to withstand high stress and force, even when working with fairly heavy loads. Initially, this device was used to connect wooden and metal structures of the most various types. It is often used during rigging work, when it is necessary to secure transported or mounted equipment, or any other heavy load. If you need to install a metal mast or antenna, then this tool will help you cope with it.
Metal appliances tend to rust if they are exposed to moisture for some time. But a stainless lanyard is protected from this disease, since it is made of special steel or treated with a zinc coating. This measure was developed for the reason that this element is very often located outside the fixed structure, and therefore is always exposed to the influence of the atmosphere.
It is necessary to choose this device based on the length and thickness of the ropes or antennas, and, despite the impressive tasks, they are solved by such little ones as lanyards, their sizes vary from 5 to 20 mm. The overall success of any construction process depends on the choice of installation device. First of all, you need to decide why it is needed. Most often, such an element is used precisely to connect and tension cables or ropes on which a heavy load will be attached.
How does this mechanism work and why?
In order to understand the structure of this device, you need to pay attention to the drawing, The lanyard from the outside looks like an ordinary coupling, which consists of two screws. Moreover, the screws used are those on which the opposite thread is applied. They are then screwed into a metal structure, often cylindrical. If of this device no, you can use a special ring. Thanks to metal structure or ring, the screws are “pulled” closer to the center, as a result of which it is tightened.
Also, in addition to rigging work, this device is widely used at home, mainly when it is necessary to tighten curtain fasteners, tune a piano (achieve a better sound, tighten the strings).
Often such a tool is made open, that is, the adjusting screws are visible. Its body is made by forging, welding or casting. After this, two holes are milled, which allow you to change the length and force using screws. They are made by turning. In cases where work is carried out in difficult weather conditions, a closed lanyard is used. Most often, this tool consists of three parts: a body, two screws (with right-hand and left-hand threads) and a screw head (fork, hook or ring).
Types of devices for tensioning cables
Before purchasing a tensioning device, you need to understand its markings., namely: C+C – hook and hook, C+O – hook and ring, O+O – ring and ring. These are the most commonly used, but there are others. In order to tighten or loosen the tension, it is necessary to rotate the “ring”, after which the screws will move either towards the center or away from it. The type of tool depends on what kind of work you are going to do. Galvanized tools are used when you need high tension force. The cargo type is used when it is necessary to either tighten the cables or attach a heavy load. Such devices can reach a weight of up to 25 kg, and this tool can withstand up to 90 tons.
The “hook-hook” type of device is used when it is necessary to change the length of a cable, mainly when installing masts or antennas. The “ring hook” is also used in such cases. The moving parts of this version of the device have threaded threads, thanks to which the length can be adjusted. There are also now options using modern technologies, using which you can adjust the smoothness of the tension. Such tools are used when working with fiber optic cables. In order to tension wires and cables under light loads, you can use closed tools.
In such cases, there is no clear value of the permissible load, so it is necessary to be guided by the fact. It should also be remembered that such devices are not used for load-bearing structures. The fork-fork option is very popular and is used quite often. It allows you to quickly change or adjust tension and length. However, this tool is not used for lifting loads. It was created in order to adjust suspensions, braces and belays. But the chain lanyard is longer than its counterparts; it is able to grab two objects that are relatively far from each other, and then pull it together, giving the required tension.
Successful work and proper operation of the lanyard
Forces that act on the mechanism of this instrument, should not cause deformation during loading. If this happens, then the tension must be reduced, and the parts that have undergone deformation must be replaced. If there is a chance of shock loading or critical mode, then before starting work, you must clearly select the product to be used. The permissible load is only permissible along the axis line. There should be no overload.
The products are also not designed to withstand lateral loads. The tensioner used must always be checked before and after work for compliance with safety standards, otherwise unacceptable critical deformations may occur. If you calculate the measurements correctly and observe all the smallest details, and also carry out preventative work and inspection of the condition of the tool, it will last as long as possible long term, and the likelihood of its breakage or deformation will be minimized.
Before starting work, it is recommended to wash the tool with gasoline, if possible polish it on a felt wheel, apply lubricant and run it dry. The best lubricants in this case are those with the addition of graphite or molybdenum bisulfate. It is recommended to turn them during work (two or three times will be enough). If the work is carried out in difficult climatic conditions, where humidity is high, then spilling will not be superfluous. fresh water on the mechanisms, which will allow you to wash off salt water. Exactly these simple rules will deprive the user of many problems, in particular, the painful unwinding of a “stuck” lanyard.
Thus, thanks to universal tool, you can do both simple work (tensioning strings, curtains) and complex work (tensioning ropes or carrying heavy loads without using additional accessories). Also using this mechanism, you can achieve best indicator vertically when installing the antenna or mast.
To connect the ends of a cable or rope, as well as to form loops at the ends, they are used different varieties steel, copper or aluminum clamps. Relating to rigging fasteners, cable clamps are used in elevator facilities, when carrying out various installation work, as well as in everyday life.
Types of clamps
To ensure durability and reliability, everything structural elements Clamps are made of stainless steel, and for light operating loads - also of copper, brass or aluminum.
The most popular are:
Features of using different types of cable clamps
Main technical parameters of the products under consideration are the maximum cable diameter and the guaranteed clamping force. The dimensions of the clamp are also important, since it is recommended, regardless of the type, to use several clamps in series (at least three), especially if the weight of the load does not guarantee its safe movement or lifting.
Clamps according to DIN 741 are used for ropes with a diameter of 5...62 mm, in the presence of a spring washer in accordance with GOST 6402-70 and a nut in accordance with GOST 5915-70. The design of this clamp allows for the installation of a locking bar, which provides more reliable clamping of the cable to the bracket. The clamping block must be made by stamping from steel grade no lower than St.3kp in accordance with GOST 380-94 (only for small clamping forces cast blocks made of steel 25L in accordance with GOST 977-75 are allowed). It is not allowed to use cable clamps whose parts do not have a protective anti-corrosion zinc coating.
IN fasteners flat clamps thread according to GOST 24705-81 must be used. The material of the linings is steel St. 3, the plates should be used for fastening cables with a diameter of 4.6...30 mm.
If several clamps are used in series, the distance between them should not be less than six cable diameters.
In Duplex type double clamps the shear force is absorbed exclusively bolted connection, therefore the choice of fastener diameter is determined by the diameter of the cable. The following ratios are recommended:
- For cables with a diameter of 2 mm and 3 mm - M4 fasteners;
- For cables with a diameter of 4 mm and 5 mm - M5 fasteners;
- For a cable with a diameter of 6 mm - M6 fasteners;
- For a cable with a diameter of 8 mm - M8 fasteners;
- For a cable with a diameter of 10...12 mm - M10 fasteners.
Wedge clamps are not recommended for lifting loads. Because the operational loads on the fastener are reduced, since the axes of force during operation of such a clamp coincide, and, therefore, shear stresses do not arise. The operational parameters of wedge-type clamps are regulated by DIN 15315. For screw clamping of a cable or rope to the supporting surface of the wedge, high-strength fasteners are used (strength class not lower than 5.6), with a protective anti-friction coating. The connection needs to be tightened periodically.
The barrel clamp is often made of aluminum, and is not designed for large cable diameters: the rational range of diameters is 2... 8 mm. The absence of protruding elements and the compactness of this clamp allows it to be used in cramped spaces.
Is it possible to make a cable clamp with your own hands?
The price of clamps, depending on their size and permissible load capacity, is, rub/piece:
- For Simplex type clamps - 4…14;
- For Duplex type clamps – 7…24;
- For clamps according to DIN 741 - 4…160;
- For wedge clamps – 200…250;
- For barrel type clamps - 3...40 (made of aluminum), and 60...160 (made of stainless steel).
In everyday life (for example, for car enthusiasts), there is often a need to make a cable clamp with your own hands. To form a reliable loop, it is advisable to use a regular aluminum (not duralumin!) tube, into which the cable should fit freely required diameter. The tube is bent in an arc, after which a cable is inserted there at a distance of 120...150 mm, its ends are covered with staples, and connected with a bolt.
When building up parts of the cable, the diameter of the pipe is chosen so that both cables can fit in freely, and from different ends. All other actions are performed in the same way. It should be noted that load bearing capacity Such a cable clamp will be determined by the bending strength of the pipe material, so the permissible force of a home-made clamping device will be noticeably lower than that manufactured by a specialized enterprise.
