Regardless of the types of road trains, traction coupling devices must provide: reliable connection of the tractor vehicle with a trailer or semi-trailer; the possibility of their relative movement; smooth transmission of forces from the tractor to the trailer when starting off; the possibility of quick coupling and uncoupling.

Traction-coupling devices of trailer road trains. For hitching trucks or tractors with trailers, the following two types of connection are mainly used: "hook - loop" and "pivot loop". On domestic cars, as well as in the USA, England and France, hook-and-loop connections are used. The kingpin-loop connection is standardized in Czechoslovakia, the GDR and the FRG.

The hook-and-loop connection consists of a towing hook mounted on a vehicle or tractor vehicle and a rigid drawbar with a loop connected to the trailer. To ensure traffic safety, even in cases of disengagement of the car and trailer, the latter are connected by emergency chains.

When a trailer road train moves at a speed of more than 40 km / h, transverse oscillations of the trailer occur - wobbling. These oscillations lead to unstable movement of the road train and cause additional stresses in the coupling devices and other components and assemblies of the road train. Trailer wobbling increases the lane width of the road train and may cause the trailer to skid. The wobbling is mainly caused by the lateral elasticity of the pneumatic tires. And the presence of gaps in the coupling and turning devices of the trailer. The wobbling of semi-trailers is much less than that of trailers. An increase in the base of trailers and semi-trailers, the installation of double wheels and the elimination of gaps in the coupling and swivel devices have a positive effect on the stability of their movement.

The disadvantage of the old designs of coupling devices of the car and the trailer is the presence of significant gaps between the hook and the drawbar loop, which lead to an increase in the wobbling of the trailer to accelerated wear of the hook and loop, as well as the inconsistency of the characteristics of the elastic element (helical spring made of square wire) to the operating conditions of the hitch (scene the hook does not provide longitudinal vibration damping). The noted shortcomings are mainly eliminated in the new designs of the towing device (Fig. 1) with an elastic element. This hitch is virtually backlash-free."

The elastic rubber element has a non-linear characteristic, so its rigidity is relatively low when starting off the road train, and increases during movement. This characteristic of the coupling device best meets the load conditions of the hook when starting and moving the road train. Elastic elements with a non-linear characteristic (ring springs, rubber bushings, etc.) are widely used in towing devices of cars of foreign companies.

Fig.1. Coupling towing device of the ZIL-130 car: 1-body of the elastic element; 2-rubber element; 3-drawing rod; 4-gozovka.

In order to improve safety and speed up the process of coupling a car with a trailer, semi-automatic, towing devices are increasingly being used abroad.

Before starting the coupling of a car with a semi-automatic towing device with a trailer, the coupling loop 1 (Fig. 2a) presses on the kingpin 4 pressed by the leash 5 with the spring 6. With further movement of the coupling loop, the kingpin first rises, and when it coincides with the hole in the loop, it enters into it. When this leash 5 is released. For uncoupling, it is necessary to raise the kingpin with the help of handle 7. To eliminate the increased gap between the hinge and the kingpin (due to wear), it is necessary to replace the bushing 2 in the hinge 1. There are guide projections 3 in the body 8 of the coupling device.

Fig.2. a - the position of the shutter in front of the hitch; b - the position of the shutter after hitching.

To eliminate wobbling of trailers, along with backlash-free coupling devices, stabilizers are used, for example, from the British company Girling. The stabilizer is a beam mounted on the drawbar of the trailer. Telescopic hydraulic shock absorbers are attached to the ends of the beam on ball pins. The other ends of the shock absorbers are connected by quick-detachable spherical joints located on both sides of the tow hook, with the cross member of the frame of the tractor vehicle. The stabilizer, along with the elimination of the wobbling of the trailer, counteracts the "folding" of the road train during heavy braking and reversing.

Two-axle and multi-axle trailers have devices for swiping the front axle. The articulation between the car and the trailer and the presence of the pivoting front axle of the trailer ensure the rotation of the car and the trailer without slipping the wheels, as well as the relative movement of the car and the trailer in the vertical and horizontal planes.

Depending on the method of transferring horizontal forces, rotary devices are divided into pivot and pivotless.

The most common at present is the pivot swivel device, which has a number of disadvantages, including bulky design and high starting resistance when turning.

The pivotless swivel found on most of the new two-axle trailers does not have these drawbacks. An inner clip is fixed on the trailer frame, and an outer clip is fixed on the trailer pivot axle frame. Steel balls are placed between them. The disassembly of the rotary device and its lubrication are carried out through plugs.

A serious disadvantage of trailers with turning circles is the mismatch between the track of the trailer and the track of the vehicle when cornering. As a result, the width of the knees of a road train is approximately 1.5 times greater than the width of a single vehicle, which significantly reduces the maneuverability of such road trains. To eliminate this drawback, the wheels of the front axle of the trailer are made steerable with the help of an automobile-type steering trapezoid. In this case, the turning angle of the wheels must be less than the turning angle of the trailer drawbar. Along with greater maneuverability, such trailers have a lower loading height and center of gravity due to the lack of a turntable. This, in turn, leads to an increase in the stability of the movement of trailers.

Traction-coupling devices of road trains-dissolutions. Depending on the type of hitch with a tractor vehicle, trailer units for long loads are divided into drop trailers, drop semi-trailers and long-wheelbase drop trailers with a front rolling cart. Trailers-dissolutions are towed by vehicles that have horses instead of platforms, semi-trailers-dissolutions are towed by truck tractors, and long-wheelbase trailers are towed by ballast tractors. At the same time, trailers and semi-trailers-dissolutions, depending on the carrying capacity, can have from one to three axles.

Trailers - and semi-trailers-dissolutions consist of a frame, a drawbar with a loop or king pin (semi-trailer), an axle (axles) with wheels, a bunk and a suspension. Some dissolution designs are equipped with a wheel steering system. The drawbars of the trailers-dissolutions end in a loop and are connected to the tractor with a hook. In front of the semi-trailer-dissolution there is a kingpin and its connection with the saddle of the tractor vehicle. The magnitude of the load on the trailer or semi-trailer-dissolution (for a given mass of cargo) varies depending on the length of the drawbar and the size of the overhangs of the cargo from the bunk. The designs of the bunk trailer-dissolution and the traction vehicle-tractor are the same. They consist of a transverse swivel beam and vertical tilting uprights.

Road trains consisting of a trailer-tractor with a hook and a dissolution trailer have the peculiarity that during transportation the transported cargo moves along the bunk when turning and deflecting the tractor and trailer in a vertical plane. This is because the centers of movement, respectively, of the load and the trailer are at different points (the axis of the front bunk, which is the point of deflection of the load, is in front of the hitch around which the trailer moves).

To exclude the movement of cargo forward and damage to the driver's cab, a "comb" or "knife" is installed on the upper edge of the bunk of the car (when transporting timber). In this case, the load will only move back along the smooth edge of the beam (or along the rollers) of the trailer bunk. The horses of such road trains are rotary. In some cases, a "slippery" coupling device is used for this purpose (the hook moves relative to the vehicle frame). In this case, both conics are rigidly connected to the load.

One of the radical ways to eliminate the movement of long loads on turns along the support beams of the bunk is the coincidence of the connection point of the trailer-dissolution with the vehicle-tractor and the turning point of the bunk of the vehicle-tractor.

A tractor vehicle can be connected to a trailer-dissolution without the usual hook and drawbar. At the same time, the traction force between the vehicle-tractor and the trailer-dissolution is transmitted with the help of a long load fixed in the cones of the vehicle-tractor and the trailer-dissolution.

When transporting goods of great length, controlled dissolution trailers are sometimes used, equipped with a steering gear. In this case, there is a helmsman on the trailer, who controls the release independently of the driver. The control of trailers-dissolutions can also be automatic (cross-hitch and steering lever or hydraulic drive, acting when the drawbar deviates from the trailer axis). Controlled trailers-dissolutions are also used in cases where the road train consists of a truck-tractor, a semi-trailer with a bunk and a controlled dissolution trailer. Such use of road trains when hauling timber can significantly reduce the downtime of a tractor vehicle at loading and unloading points,

Traction-coupling and supporting devices of truck tractors. The most common coupling device for truck vehicles - tractors and semi-trailers consists of a saddle located on the vehicle frame and a kingpin on the semi-trailer.

To ensure the mutual movement of the vehicle-tractor and semi-trailer, modern fifth wheel coupling devices on the vehicle-tractor have two rolling axes (transverse and longitudinal) and a king pin rigidly fixed to the semi-trailer. Such a semi-automatic fifth wheel with two swing axes (Fig. 3) has the following device. On the frame of the tractor vehicle with an offset relative to the rear axle (inside the base by 50-150 mm), a plate 8 is installed with a support circle 4 hinged on it, having a mouth 19. The support circle fixed on the balancer 2 can swing on the axis 3 in the longitudinal, and on the axis 7 in the transverse planes. To dampen the swing of the circle in the transverse plane, there are two cylindrical springs 6 and limiters 5. In the center of the support circle, the kingpin grips 18 are fixed, hinged on the fingers 17 and having bevels in the front. The bevels in the back of the grips coincide with the bevels: the mouth of the reference circle. In the front part, the grips have shaped cutouts into which the lock 15 is inserted. The lock has a rod 13 on which the spring 14 and the lock lever 16 are put on. The lock has a longitudinal cutout, which includes a guide pin 12. fixed at the bottom of the support circle. When the semi-trailer is connected to the tractor vehicle, the grips 18 are brought together and cover the semi-trailer kingpin. In this case, disengagement is impossible due to the fact that the lock 15 prevents the rotation of the grips on the fingers 17.

The uncoupling of the semi-trailer is carried out by retracting the fuse to the side of the bar 1 and moving the lock 15 forward using the lever 16. In this case, the spring 14 is compressed. The latch 11 in the lock, pulled by the spring 10, abuts against the lug of the lock and holds it in the forward position.

Fig.3.

When uncoupling, when the tractor vehicle moves forward, the semi-trailer kingpin pushes the grips apart. At this moment, the pin 9 on the left grip, pressing the latch, turns it and releases the lock, which, under the action of the spring 14, moves all the way into the grips.

When hitching, the tractor vehicle moves back and the semi-trailer kingpin, falling into the mouth of the support circle, presses on the internal bevels of the grips, pushes them apart and sets them to the working position. At this moment, the lock is automatically pushed by a spring into the groove formed by the front ends of the grippers and locks the hitch. After that, the fuse bar 1 is lowered, preventing the possibility of axial movement of the lock and, consequently, the uncoupling of the road train on the way. The support circle can swing on the transverse axis up to 35°, and on the longitudinal axis up to 20°. In many cases, the fifth wheels of tractors and semi-trailers have shock absorbers in the form of longitudinal coil springs or rubber stops to mitigate shocks when starting off and during movement.

Semi-trailer cylindrical kingpin has a flange in the lower part that prevents the kingpin from coming out of the support circle lock during non-synchronous vertical movements of the tractor and semi-trailer.

Semi-trailers, as a rule, do not have special devices for correcting their trajectory when turning the tractor. In cases where the semi-trailer has two axles (tandem), one of them is turned or mixed relative to the other in order to reduce tire wear when driving on different tracks. The semi-trailer in this case follows the track of the tractor vehicle to a "limited extent".

The location and dimensions of the fifth wheel coupling of tractors that do not transmit power through the king pin to drive the active axles of the semi-trailer or various mechanisms installed on the semi-trailer must comply with applicable standards.

The use of standard fifth wheel couplings on road trains allows coupling and uncoupling of tractors with all semi-trailers.

To increase the transverse stability of road trains, and especially when transporting liquids in tanks, some US firms manufacture fifth wheel devices with pneumatic locking of locking mechanisms that provide a choice of clearance between the grippers and the semi-trailer kingpin.

Fig.4. a - supply of a tractor vehicle under a semi-trailer; b - coupling process: c - tractor is coupled to a semi-trailer.

The coupling device ("compensator") from Holland Hitch automatically stabilizes the loaded tank, tilting it in the opposite direction when the tractor rolls sideways. The firm "Fontain Truck Equpment" produces saddle devices, in which mechanical blocking is combined with the choice of the gap between the kingpin and the grips of the plate. axle (or axles) and fifth wheel.

Along with the pivot-type saddle device, automatic pivot-less saddle-mounted devices are used abroad, for example, Autosafe by the "Hands" company (Fig. 4). In this case, guides 5, a curved bar 15 located in the middle between the guides, locking hooks 8 (there are two of them) and locking hooks 6 of the locking hooks are installed on the tractor, and a turntable 4, guide rollers 3 and rollers 1 of the support device are installed on the semi-trailer. The coupling process is as follows: the tractor is reversed under the semi-trailer (Fig. 4. a): the guide rollers 3, rolling along the guides 5 of the tractor vehicle, raise the semi-trailer (Fig. 4, b) and at a certain moment the rollers 1 of the supporting device come off from the earth. In the process of further movement of the tractor vehicle in reverse, the hinge 13 of the support device is pushed out of the latch 16 attached to the support posts 2 by a curved bar 15 (Fig. 4. c). With further lifting of the support legs, the spring 11 of the locking mechanism of the support device is stretched, the upper parts of the locking hooks 8 rest against the guide rollers and, rotating around the axes 7, turn counterclockwise until the front part of the locking hook, having overcome the resistance of the spring 10, turns down the latch 6 At this time, the guide rollers are captured by hooks 8, which are locked by latches 6, and the road train is ready to move. Arriving at the destination, the driver, by means of the thrust 9 brought into the cab, releases the latches and moves the towing vehicle forward. The guide rollers of the semi-trailer roll along the guides of the tractor car, the spring 11, compressing, turns the levers 12 and 14. which lower the racks to a vertical position, while the hinge 13 enters the latch 16 (see Fig. 4. b). According to the scheme described above, most automatic pivotless devices work.

The speed of coupling and uncoupling of tractors and semi-trailers largely depends on the designs of semi-trailer support devices.

On domestic semi-trailers, support devices with a mechanical manual drive are most widely used. In this case, the drive can be common for two supports or separate for each support. Recently, support devices with electric and hydraulic drives are beginning to be used.

The supporting device of the Minsk Automobile Plant has a separate mechanical manual drive for each support. In the transport position, the supports are removed (rotate around the hinges) and fixed on the frame. The split drive provides more comfortable hitching and unhitching on uneven ground and slightly reduces the effort on the handle required to raise and lower the uprights. The disadvantage of this support device is that in order to raise and lower the supports, the driver has to move from one side of the road train to the other.

Fig.5. A - tractor vehicle; B - semi-trailer: 1-oil tank. 2 - valve block; 3 - connecting head; 4 - shut-off valve; 5-6 - cylinders of support devices; 7 - base plates; 8 - pump.

This leads to an increase in the time required for coupling and uncoupling the road train.

On heavy-duty road trains, support devices that do not require manual labor, for example, with a hydraulic drive, should be most widely used (Fig. 5). This device consists of two hydraulic cylinders, into which oil is pumped by a pump driven from the engine of the tractor vehicle through the power take-off.

Before uncoupling the semi-trailer, oil is supplied to the cylinders of the support device by a pump and the supports are extended. Overlapping the control valve fixes the supports in the extended position. After hitching the tractor and the semi-trailer, the control valve is opened and the oil is squeezed out into the tank under the action of the springs and the supports rise.

Such a supporting device can be used on semi-trailers coupled with standard tractors equipped with hoses having coupling heads. If necessary, the support legs can be raised or lowered manually using a pump mounted on the semi-trailer. The time for lowering and raising the racks using a pump driven by an engine is 1.0-1.5 minutes. This completely eliminates manual labor. The disadvantages of the hydraulic support device include oil loss when connecting and disconnecting the hoses of the tractor and semi-trailer, as well as the deterioration of the drive at low air temperatures (oil thickening).

In road trains, for the articulated connection of the tractor and trailer and the possibility of their quick coupling-uncoupling, as well as the transfer of vertical and longitudinal loads, towing devices of various designs are used.

A significant number of manufacturing companies are engaged in the production of towing devices (TSU), among which the most famous Jost, Rockinger (since 2001 part of Jost. - Note. ed.), Ringfeder (part of VBG since 1997 – Ed.), Helmut Buer GmbH & Co. KG (Germany), Georg Fisher (Switzerland), Coder Ture (France), V. Orlandi (Italy), VBG (Sweden), York (Great Britain), Fontaine Truck Equipment, SAF-Holland, Utility Trailer (USA), etc. Russian manufacturers should also be added to this list.

Drawbars are designed to transfer large longitudinal and small vertical forces, which should not exceed 10 ... 15 kN. This is their main functional feature. Such mechanisms must be highly reliable, provide appropriate folding angles of the road train, the possibility of quick and safe coupling and uncoupling, and damping of dynamic loads during the movement of the road train. Fundamentally, the tow hitch consists of detachable-coupling and shock-absorbing mechanisms, as well as fastening elements. It is clear that the design of traction coupling devices significantly affects such important operational qualities of a road train as handling, directional stability, maneuverability, smoothness, cross-country ability, reliability and safety.

According to the type of detachable coupling mechanism, the hitch is divided into three main types: hook (pair of hook-loop), fork or pivot (pair of kingpin-loop) and ball (pair of ball-hemisphere). Other varieties of significant distribution in commercial vehicles have not been found, and therefore are not considered.

TSU ball type

Tow hitches of the ball-hemisphere (ball-loop) type are often, although somewhat erroneously, called towbars. They are used to tow caravans and light trailers with a total weight of up to 3.5 tons by a vehicle. Structurally, such mechanisms are made in the form of single-axle trailers or trailers with a double or three-axle centrally located bogie. Typically, the role of tractors are cars, pickups, minibuses and light trucks. All requirements for this type of TSU are set out in the ISO 1103 standard and the corresponding domestic GOST 28248-89, GOST 30600-97 and OST 37.001.096-84.

A coupling ball is installed on the tractor vehicle (GOST 28248 provides for a single ball diameter of 50 mm), and a mating coupling head (sphere) is mounted on the drawbar of the towed trailer. An important point for the entire design of the TSU is its fastening to such elements of the body or frame of the tractor that can withstand the required number of loading cycles by periodic loads and limiting static loads. Consequently, the sufficient bearing capacity of the DH is determined by the correct choice of its structural dimensions, i.e., by the compliance of the strength of the device with the loads acting on it during operation. TSU ball type according to the requirements of the standards must be tested for fatigue strength of the structure. In addition to the mechanical connection, the towing device provides an electrical connection between the electrical equipment of the traction vehicle and the equipment of the towed trailer.

Towed trailers are divided into light and heavy - the maximum permitted weight, respectively, is not more than 750 and more than 750 kg. By the type of ball and fastening, the ball-type hitch hitch differs in versions - A, B, C, F, G, H and N. Small-tonnage "Sables", "GAZelles" and "Bull-calves" in most cases are equipped with a hitch type F with a load capacity of up to 2 tons, equipped with a forged ball with two mounting holes.

Hook hitch

In our country, hook-and-loop devices are most widely used due to far from optimal road conditions. Such DHs are characterized by simple design, ease of manufacture, relatively low weight and large flex angles. The latter circumstance makes them indispensable for the movement of road trains in difficult road conditions and on terrain with a variety of terrain. The described design implies the presence of large gaps (up to 10 mm) in the hook-and-loop connection to facilitate hitching and uncoupling. These gaps lead to an increase in dynamic loads and intensive wear of the device parts (mating pair), and also cause the hitch (hook and drawbar loop) to fail. The design of hook devices provides, as a rule, manual coupling-uncoupling of the links of the road train.

The standard size of the hook hitch is selected depending on the gross weight of the trailer. The main parameters are regulated by international standards ISO 1102, ISO 3584 and ISO 8755 or national regulations. Hook-and-loop devices are produced for the internal diameter of the loop 76, 85 and 95 mm. The diameter of the loop bar of the first size is 42 mm, the other two - 50 mm each. The coupling of tractors and trailers equipped with towing devices of various dimensions is ensured by replacing the corresponding elements of these mechanisms or by installing transition devices. The weight of the hook-type hitch usually does not exceed 30 kg.

In practice, the “hook-loop” device allows the coupling loop to be rotated around the horizontal longitudinal axis of the hook by 360°, rotated in the vertical plane by ±45°, and rotated in the horizontal plane by ±90°. There are manual and semi-automatic designs of hook hitches. The latter are less common due to their great complexity and increased mass.

In Russia, GOST 2349-75 is in force. Depending on the standard size of the DH, the installation height above the supporting surface and the connecting dimensions are regulated. For hook hitches of sizes from 0 to 3, the geometrical parameters of the mating surfaces of the hook and loop mouth are the same (diameter of the loop bar is 42 mm). Size 4 provides for the use of a hinge made of a bar with a diameter of 45 mm. According to the domestic standard, hook devices must provide flexibility angles relative to the transverse axis passing through the mouth of the hook, not less than ±40°, relative to the vertical axis ±55° (for general transport vehicles with high cross-country ability, not less than ±62°) and longitudinal axis ±15°. The hook must rotate freely around its longitudinal axis, and at the request of the consumer, it can be equipped with locking devices that allow it to be fixed when the trailer is uncoupled. The design of the lock must exclude the possibility of self-uncoupling of the road train during movement, and also have at least two safety mechanisms that operate independently of each other, and at least one of them must not be under the influence of forces that appear during the movement of the vehicle.

For the first four categories of standard sizes, one throat size is adopted, equal to 48 mm, the jaw size is 74 mm, which makes it possible to use a wide range of tractors and trailers when completing road trains. In the fifth group, the opening size is 52 mm, while the jaw geometry remains the same.

The standard hook-type coupling, equipped with double-sided damping, consists of a towing hook mounted on the tractor and a rigid drawbar with a drawbar connected to the trailer. The towing hook is usually mounted on the drawbar of the frame, however, on some vehicles, it can perform its function no less effectively, being located on the front bumper (crossbar) of the frame or on the drawbar of a trailer (semi-trailer) for towing a second trailer. The "hook-loop" system consists of the hook itself, a cap latch, a safety lock with a locking cotter pin. The presence of a safety lock and cotter pin prevent spontaneous uncoupling of the road train during movement. At the front end of the hook rod, installed in the sleeve, a nut is screwed, which, together with the sleeve, ensures the correct longitudinal movement of the hook. Inside the case, a rubber elastic element in the form of a hyperboloid is inserted, crimped by washers. When compressed, it changes shape in such a way that it fills the space in the case. In other designs of traction hooks, ring, helical cylindrical or conical springs are used as elastic elements.

During operation, the nut cannot be used to adjust the axial movement of the hook, since its screwing-in and folding leads to an increase in the axial movement of the hook. When shrinkage of the rubber buffer occurs, additional ring gaskets are installed between the flanges and the rubber buffer. The use of a trailer coupling eye with a smaller section increases wear and reduces the service life of the tow hitch, as well as the rear cross member of the vehicle frame.

Despite the inherent shortcomings of hook-and-loop hitches, all leading manufacturers of such products continue to improve and produce them. Hook devices are distinguished by a wide variety of designs of both the hook itself and the lock. To implement backlash-free coupling, a number of companies have developed special designs of hook-and-loop couplings, in which the gap can be selected automatically using conical rollers (Coder Ture) or using springs or pneumatic devices according to the “backlash-free hook” or “backlash-free loop” principle (Utility Trailer). Similar systems for hook hitches are produced by V. Orlandi and SAF-Holland. They are equipped with a pneumatic drive that automatically selects the gap in the lock of the device. As a power element, a pneumatic chamber with a movable rod is used, mounted on the rear side of the rear cross member of the frame. Nevertheless, backlash-free couplings have not found wide application due to the significant complication of design and maintenance, as well as an increase in their own weight (up to 60 kg).

When it comes to trailers, novice motorists confidently discuss the issues of carrying capacity and maneuverability. But the questions of the towing device are perplexing only because of the definition of the concept. Is it a hitch for a light trailer, or a trailer coupling head, or maybe a drawbar - is it a tow bar ?!

The benefit of acquiring a branded towbar for a car is understandable. What is a towing hitch (drawbar) or a towbar - this is a hook with a metal ball sticking out below the bumper for throwing a hitch head on it, mounted on the end of a straight or V-shaped trailer drawbar. When there is a need to transport cargo that does not fit in the passenger compartment or trunk, the choice of a trailer is accompanied by questions about the tow bar. After all, depending on the fastening, the permissible load on the car frame is calculated. Of course, the weight tables are on the certificates and on the back of the bonnet. But what if the hitch is not installed?

Definitely:

• Look for a suitable or native brand;
• In the absence of custom-made or independently.

What is a tow hitch

In practice, two types of TSU have taken root in Russia:

The advantage of this design is the possibility of equipping the trailer with a brake system that will work by means of transmitting mechanical vibrations through the ball to the coupling head and ensure leveling of speed differences on the road: the car slows down, the trailer presses the lever on the ball by inertia, the brakes are turned on.

Homemade TSUs try to fit into the specific features of the destination. Otherwise, operation may be prohibited. There are many models on the market. All of them are different:

• By weight classification;
• By design;
• fastening method;
• Electrical fastening features.

Towing with non-standard values ​​can lead to bad consequences. Therefore, the classification of towbars begins with the weight load. Fitting in with your group will ensure long-term viability.

1. For passenger cars with a permissible trailer weight of 1.5 tons;
2. For station wagons, minivans with a similar value up to 2.5 tons;
3. For minibuses, SUVs up to 3.5 tons.

TSU classification:

European design. The difference from domestic ones is the size of the ball, which is marked in inches:

• 1- 7/8 is equal to 47.6 mm;
• 2 is equal to 50.8 mm;
• 2-5/16 - 58.7 mm.

American design. It's a slightly different story. They have the shape of a quadrangular shaft, into which a drawbar tip is inserted with a lock in the form of a hook-shaped handle.

The mounting method involves three types of devices:

Classification of towbars:

The tow hitch is the meeting point of the automotive electrics and the trailer. A socket with 7, 13 or 15 pins is usually mounted on the towbar, and the trailer wiring assumes a similar plug. It happens that the plug and socket turn out to be with different contact options. Choosing a trailer with the right pinout in advance will eliminate the problem. But if this happens, an adapter comes to the rescue.
Manufacturers of towbars, offering their products to the mass consumer, are responsible for the quality of the material and the resistance of the elements in the assembly, which can only be checked in the factory. The requirements of OST 37.001.299 regulate the characteristics. Handicraft towbars live and successfully disguise themselves as original samples. It is good if the craftsman knows the formula for the distribution of weight relative to the car body and the installation of fastening points, but no one guarantees the reliability of the metal.

How to install a hitch

Mounting a towbar on a car

TSU is attached to the frame or body of the car. The bumper is usually removed and its role goes to the main beam of the trailer. In some cases, it is necessary to drill a spar and install embedded plates. But installing a native towbar is a simple matter. If the car manufacturer has provided mounting points, holes and other elements for installing the towbar, and there is also a document (usually a certificate upon purchase) with the characteristics of the original device, then self-assembly is quite legal and logical. The service will offer a certain price. This will pay off if it is planned to drill additional holes or install a non-native towbar, but suitable in terms of characteristics. The service will issue a written opinion on compliance with the standards.

The condition of the ball and the TSU itself requires constant checking for the presence of:

• Loose, stripped nuts or bolts (grover will prevent loosening, but not stalling);
• ball lubricants;
• Cleanliness of the outlet;
• Weld seams.

The ball experiences critical loads and is subject to wear. It is necessary to measure the diameter every 1-1.5 thousand kilometers.

Tow hitch manufacturers

Finally, you can give a list of well-known manufacturers of TSU:

• Bosal - 200 samples for cars and trucks from Belgium;
• Brink - the leading position from Holland;
• VFM is a Russian association under the flag of Bosal;
• Westfalia is a large German company. More than 800 items;
• Aragon - Spanish leader;
• HiddenHitch is a North American company;
• AvtoS - Russian company produces trailers and towbars;
• BALTEX is a domestic company from St. Petersburg.

Video review of towbars Bosal

When the picture is clear, there is no point in wasting time and inventing what is already in the best possible way. A sound approach to the solution of cargo transportation and competent installation of the towbar will certainly lead to success. And lovers of inventions should at least focus on the owners of golden hands.

When operating a trailer, the owner will not only need specific driving skills, but some knowledge about its device will also come in handy.

Basic concepts

Trailer - a vehicle not equipped with an engine and intended for movement in combination with a power-driven vehicle.
A tractor vehicle (hereinafter referred to as a car) is a mechanical vehicle towing a trailer.
The curb weight of the trailer is its own weight with a spare wheel (if the trailer is equipped with it), without cargo.
Permissible maximum or gross weight - the weight of the equipped vehicle with cargo, driver and passengers, set by the manufacturer as the maximum allowable.

Trailers for cars are divided into light and heavy.
Light - trailers with a maximum authorized mass of not more than 750 kg.
Heavy - trailers with a maximum authorized mass of more than 750 kg. It is mandatory to be equipped with a brake system.

Rules for registration of trailers for passenger cars in the Russian Federation

Trailers for cars must be registered with the traffic police. When selling through a retail network or during customs clearance, a vehicle passport (PTS), a reference account and a "Transit" license plate are issued for the trailer. The PTS contains information about the make and model, as well as 1 identification number (VIN), year of manufacture, gross weight, body and / or frame number. A reference-invoice is a document confirming the right to own a trailer. Transit numbers give the right to transport it to the place of permanent registration. The trailer must be registered at the place of residence of the owner no later than 5 days after its purchase, deregistration or customs clearance, or during the period of validity of the "Transit" registration plate. When registering at the place of residence, the owner is issued a certificate of registration and a registration plate.

Trailers are subject to technical inspection once every two years if no more than 5 years have passed since the year of their manufacture (including the year of manufacture), and once a year if more than 5 years have passed. The month of presentation of the trailer for inspection is indicated in the technical inspection coupon. As a rule, it is set the same as that of the car with which the trailer is operated, or is selected in accordance with the last digit of the state registration plate.

Operating rules

Drivers with a category "B", "C" or "D" driving license may operate a light trailer. With category "B" you can use a trailer only if its maximum authorized mass does not exceed the mass of the equipped vehicle, and the sum of the maximum authorized masses of the vehicle and trailer does not exceed 3500 kg. Otherwise, as well as for towing a heavy trailer, a category "E" driver's license is required.

Tractor vehicle equipment

To tow a trailer, the tractor vehicle must be equipped with a special towing device (hereinafter referred to as the Hitch) and a socket for powering the trailer's electrical equipment. There are two main types of TSU:

• loop-bracket with a clamp. It consists of a bracket into which a ring is inserted, fixed on the trailer hitch assembly and a pin fixing the ring in the bracket. Widespread on trucks and off-road vehicles;
• backlash-free ball coupling. It consists of a coupling ball with a diameter of 50 mm (standard in the Russian Federation OST 37.001.096-77, international standard ISO-1103-76) and a metal structure, with which the hitch is rigidly attached to the rear of the car body.

Various models of the tow hitch can be attached to the car body through the bumper brackets and (or) directly to the load-bearing elements of the body and the trunk floor. Among domestic cars, only the VAZ-2108-15 family has standard attachment points for the TSU. When installing the device on other vehicles, self-marking and drilling of mounting holes is assumed. On most vehicles, it is usually necessary to remove the rear bumper before installing the hitch.

There are collapsible designs of the hitch that allow you to remove the hook with the coupling ball.

The socket is fixed on a special bracket of the TSU. It connects to the appropriate wires in the vehicle's rear wiring harness (in the trunk near the reversing lights). The colors of the harness wires going to the corresponding lights are indicated in the car's electrical diagram. The most common contact diagram of the TSU socket for passenger cars is shown in fig. 1.

If the trailer is wider than the tractor and closes the view through the standard rear-view mirrors, then rear-view mirrors on extended brackets must be installed on both sides of the car. The trailer must be equipped with two wheel chocks for installation under the wheels when stopping on slopes.

Classification of trailers by purpose

Trailers for passenger cars are divided into universal trucks, designed to transport various goods, and trailers for special purposes.

Special purpose trailers include:

• dump trucks for transportation of bulk cargoes;
• tanks for the transport of liquids;
• trailers for transporting equipment - boats, hydro or motorcycles, snowmobiles, etc.;
• trailers-car carriers for transportation of cars;
• tourist trailers for luggage and comfortable rest of tourists;
• trailers-dachas - with a volumetric body, designed for rest and overnight stay of tourists in the parking lots. Usually equipped with a gas stove, water tanks, dry closet, etc.;
• commercial trailers - mobile pavilions for trade, equipped with the necessary equipment (refrigerator, display case, etc.);
• trailers for transporting animals (for example, racehorses).

Trailer device

The main components of the trailer are the frame, drawbar, body and suspension.

The frame of universal cargo trailers is usually made in the form of a metal welded structure, consisting of two longitudinal spars and two to four crossbars. Trailers for transporting equipment have a space frame.

Drawbar - A-shaped or I-shaped horizontal arm mounted on the front side of the trailer frame. On the drawbar there is a hitch assembly, safety cables, a folding stand (for some trailers).

The drawbar can accommodate a trailer spare wheel. The drawbar can be folding (when folded it is removed under the bottom of the trailer) or removable and equipped with an extension for transporting long loads. Some types of folding drawbar allow you to tilt the body back without disconnecting the trailer from the tractor, which is convenient when unloading bulk cargo, such as sand.

The bodies of universal cargo trailers are metal welded or prefabricated galvanized or painted. There are also models with a metal frame and wooden floor and sides. The tailgate, and sometimes the rest, can be folded down, making it easier to load and unload the trailer. Some models have extension boards that increase the usable volume of the body. Most universal trailers are equipped with a removable rubberized awning, which is mounted on a collapsible metal frame.

Trailers for the transportation of equipment instead of a body are equipped with special, as a rule, adjustable lodgements (skids), on which the transported cargo is laid. The most expensive models have a fiberglass floor and roof, and are also equipped with winches and a lowering platform for easy loading and unloading of equipment.

In car transporter trailers, the body is a massive platform adapted for reliable fastening of the transported vehicle. Such trailers are equipped with a powerful winch, thrust racks that prevent the platform from lowering during loading, and perforated ladders that prevent the vehicle's wheels from slipping.

Bodies of caravans and commercial trailers are made of multilayer panels (so-called sandwich panels 2) mounted on a metal frame.

The body of a tourist trailer is a plastic or metal box, inside of which a folding tent house is placed.

Suspension

Trailers for passenger cars can be single-axle or two-axle. A trailer with two axles, the distance between which is less than 1 m, is called a twin axle trailer. On single-axle trailers, the following types of suspensions are most widely used.

Hubs and wheels

Manufacturers equip trailers with hubs of their own design or use a hub similar to a car hub (usually Zhiguli, Moskvich-2140 or GAZ-31029). Some trailers allow the use of two types of wheels, both "Zhiguli" and "Moskvich". As a rule, tube tires are mounted on the trailer wheels, for which the norms of the residual height of the tire tread pattern are set, similar to the norms for tractor tires (correspondingly 1.6 mm for cars). It is not allowed to install diagonal tires on one axle of the trailer together with radial tires, as well as tires with different tread patterns. The required tire pressure at different levels of trailer loading is sometimes indicated in the trailer's operating manual.

brakes

Trailers can be equipped with the following types of brake systems.

Service brake system - designed to brake the trailer when towing. It is not linked to the working brake system of the car, but comes into operation depending on the load acting on the hitch assembly (the so-called inertial type overrun brake). The system consists of a control device (Fig. 2) located on the hitch assembly and wheel brakes (usually drum brakes). When the car slows down, the trailer begins to "catch up" with it, resting against the hitch assembly. This force through the piston and the system of levers and rods actuates the wheel brakes. When the braking of the vehicle stops, the "pushing" force on the hitch assembly disappears and the brakes stop working. Longitudinal vibrations of the trailer, which can cause the brake system to work, are damped by a horizontal shock absorber. This design allows you to transfer to the wheels of the trailer a braking force proportional to the deceleration of the car. When reversing, most trailers require a forcible disengagement of the service brake system, however, there are models whose mechanics of the service brake system “distinguishes” between braking and reversing.

Parking brake system - designed to brake the trailer in the parking lot, both together with the car, and separately from it. It consists of a parking brake lever, similar to a car's handbrake, which acts on the drive of the service brake system.

Emergency braking system - designed for emergency braking of the trailer in case of violation of the coupling with the tractor. It is carried out in the form of an additional safety cable, which includes the drive of the wheel brake mechanisms in the event of a break in the tow hitch during movement.

According to the SDA, the braking distance of a car with a trailer, both equipped with a working brake system and without it, when braking on even dry asphalt from a speed of 40 km / h to a complete stop, should be no more than 13.6 (14.5) m 3.

Light signaling and electrical equipment of trailers

All trailers are equipped with light signaling devices. Mandatory devices include:

• two rear direction indicators in orange;
• two rear brake lights in red;
• two rear marker lights in red;
• white license plate light;
• one or two red rear fog lamps 4 ;
• two rear triangular red reflectors (the tops of the triangles must be directed upwards);
• two front non-triangular white reflectors;
• two lateral non-triangular orange reflectors.

In addition, trailers wider than 1.6 m must have two white front marker lights, and trailers longer than 6 m two orange side marker lights.

Electrical appliances are powered from the car through the socket on the TSU. To do this, a plug is attached to the drawbar of the trailer. As a rule, trailer wiring is carried out according to a single-wire circuit: minus ("ground") - on the trailer body, and plus - through wires).

Caravan trailers and commercial trailers are equipped with internal electrical equipment: interior lighting (standby lighting 12 V), on-board plug and cable socket for connecting to an external 220 V network, switchboard, showcase lighting, forced exhaust ventilation and other additional equipment. The electrical equipment of such trailers is usually carried out according to a two-wire circuit.

Recommendations

When choosing a trailer for a car, you should pay attention to the following:

• its dimensions must correspond to the intended place of storage of the trailer;
• the same standard size of the wheel hubs of the trailer and the car will allow you to get by with one spare wheel. Otherwise, you will have to carry an additional spare tire.

Immediately after purchase, the trailer should be equipped with a jack. Many trailers do not have standard jack sockets on the body, and the use of most standard car jacks is difficult. Such trailers are best lifted with a hydraulic telescopic or rhombic jack with an extended handle, substituting it under the trailer suspension arm or beam.

When installing the TSU on a car, it is desirable:

• process the holes for its fasteners with an anti-corrosion compound (for example, "Movil");
• connecting the TSU socket to the vehicle wiring, solder and carefully insulate all connections;
• generously lubricate the coupling ball with grease (for example, "Litol-24");
• close the coupling ball with a cap, which will reduce the adherence of dust and sand to it, leading to abrasive wear of the ball and the coupling assembly. In addition, it will help not to get dirty when loading or unloading the trunk of the car. A homemade cap can be made, for example, from a tennis ball.

Proper trailer loading largely determines traffic safety. The load should be placed evenly so that its center of gravity is above the axle (or between the axles) of the trailer. Shifting the center of gravity forward will cause excessive load on the towbar and the entire rear of the vehicle, reducing the traction of the steered wheels with the road. Moving rearward will cause the rear of the vehicle to rise, which will reduce rear wheel traction. The higher the center of gravity of the load, the more prone the trailer is to pitch and roll, which impairs handling. All cargo must be securely fastened.

The maximum permissible load on the tow ball is indicated in the trailer and car manual and, as a rule, ranges from 30 to 90 kg. The load is easy to measure with a floor scale. To do this, install a board 35-45 cm long with one end under the hitch assembly, and with the other - on the floor scales. To adjust the weight distribution of a loaded trailer, you can use a small load and a spare wheel.

Driving with a trailer has a number of significant differences from conventional driving.

When servicing a trailer, special attention should be paid to the hitch assembly. The cause of knocking in the area of ​​the hitch may be the play between the hitch assembly and the hitch ball. If there is no wear indicator, then the play is determined on the trailer connected to the vehicle by a sharp vertical swing of the drawbar.

Before each trip you must:

• check the presence of lubrication in the hitch assembly mechanism;
• check and, if necessary, eliminate by adjusting the play between the coupling unit and the coupling ball;
• adjust tire pressure;
• make sure that the safety ropes or chains are connected securely;
• Check the operation of the trailer lights.

The editors would like to thank the trailer manufacturers who provided technical data for the summary table for their help in preparing the materials.

1 Some manufacturers did not assign VINs to trailers; it is possible to record "the year of issue is not established"; in the absence of information from the manufacturer, the gross weight may not be indicated; body and / or frame number may be missing (in this case, the mark "w / n" is put).
2 For example, the outer side is painted aluminum or plastic, the filler is heat-insulating material, the inner side is plywood.
3 For vehicles whose production was started before 01/01/1981.
4 It is allowed to operate previously produced trailers in which the device is not provided by the manufacturer.

"Useful pages", 2001, issue 9, p. 202

Catalog of trailers for cars

Tow hitch catalog

Posted: September 9, 2010

Chapter 2

CONSTRUCTION OF TRAILERS AND SEMI-TRAILERS

2.1. Towing devices for trailers and semi-trailers

An important condition for the effective use of road trains is interlocking, which refers to the possibility of coupling a car or tractor with various trailer links.

The towing device of tractor vehicles is a towing device, and trailers - a coupling loop and a drawbar.

The main part of the towing device is a traction hook (Fig. 4, a). There are 5 standard sizes of traction hooks for tractors (Table 8). From Table. 8 it can be seen that, depending on the operating conditions of road trains, with the same standard size of the traction hook, the weight of trailers is reduced by 2 times if it is operated on dirt roads and terrain, compared with a trailer used on roads of the general network.

To ensure interlocking, the diameters O (see Fig. 4) of the mouth of the hook and the bar and the coupling loop are made the same for all standard sizes of traction hooks.

The radial clearance in the drawbar is a very important parameter. Its nominal value is 6-7 mm. Increasing the gap as the hook and loop is used increases the dynamic loads in the drawbar and therefore reduces its life. If the gap is less than the nominal size, there are great difficulties when coupling the tractor and trailer.

Traction hooks on tractor vehicles determine the shape of the drawbeam. The number and diameter of the hook mounting holes and their location are standardized. This allows, if necessary, to rearrange the traction hook from one tractor vehicle to another. These dimensions are accepted by the international organization for standardization ISO, and, therefore, allow group interchangeability of domestic and foreign tractor vehicles operated in our country.

Table 8. Dependence of standard sizes of traction hooks on the gross weight of the trailer

The towing device (Fig. 5), mounted on the frame of a tractor or trailer for coupling with the next trailer, consists of a hook rod 3, which passes through the holes in the rear cross member of the frame. The rod of the traction hook is inserted into the guides 9 and 4. In this case, the guide 4 is a continuation (welded) of the body 1 of the towing device. The necessary preload of the rubber elastic element 5, installed between the plates 2, is created by the nut 10. The rubber elastic element softens the load on the towing device when starting the road train from a standstill, as well as when driving it on an uneven road. There are designs of towing devices, and in which a spring is installed instead of a rubber elastic element. A lock 7 with a latch 6 is installed on the axis 5 passing through the hook body, which prevents the trailer drawbar from disengaging from the hook.

For saddle road trains, a fifth wheel coupling is installed on the vehicle, and for semi-trailers - coupling pins. The dimensions of the coupling pins of semi-trailers and the grips of detachable coupling mechanisms of tractor vehicles to ensure the interchangeability of domestic tractor vehicles and semi-trailers are regulated by GOST 12017-81.

In accordance with the requirements of GOST 12017 - 81 and based on the condition for ensuring the strength of parts of the towing device when towing trailers of various weights, two corresponding groups of sizes have been introduced.

The diameter and (Fig. 6) of the kingpin for semi-trailers with a gross weight of up to 40 tons is 50.8 mm + 0.1 mm. and the diameter of the th hole of the grips corresponding to it is 60 mm + 0.1 mm. For semi-trailers with a gross weight of 40 to 100 tons, the nominal size of the diameters has been increased to 89 mm with the same tolerances. Thus, in both cases, the required initial clearance of 0.3-0.5 mm is guaranteed in the coupling joint.

Of particular importance are the connecting dimensions (Fig. 7), which ensure the free movement of the towing vehicle relative to the semi-trailer and the necessary space between the cab of the towing vehicle and the front part of the semi-trailer. The values ​​of the specified dimensions are set depending on the number of rear axles of the tractor or semi-trailer and on the permissible load on the saddle.

The difference r-r 3 determines the front clearance between the cab of the tractor and the front side of the semi-trailer, and the difference r 2 -r y - the rear clearance between the rear end of the frame and the support device. The main purpose of the gaps is to ensure the mutual movement of the tractor and the semi-trailer relative to the axes of the fifth wheel coupling. During normal operation of road trains, the gaps should be at least 80-150 mm; in more difficult road conditions, they should be increased.

To ensure the normal coupling of the road train, it is necessary that N - / g< И яг. Высота Н т. опорного листа не регламентируется, но указывается в инструкции по эксплуатации полуприцепов. Ее можно регулировать опорными устройствами.

The most important design parameters of the road train are the angles of flexibility (Fig. 8), which determine the possibility of its movement over uneven roads. The values ​​of the angles of flexibility are determined by the design of the fifth wheel coupling and can vary within P = "± 15 °; y = ±6°; a - not less than ±100°.

On most truck tractors, a fifth wheel coupling is used (Fig. 9), which provides the necessary flexibility angles. The fifth wheel coupling is mounted on a stand bolted to the frame of the tractor vehicle. Two brackets 3 with hinges 9 are rigidly connected to the stand. The saddle 2 is connected to the brackets by two axes 4, which are fixed by locking plates 6 from axial movement and rotation. Free rotation of the axes of the saddle on the bushings of the hinges ensures the longitudinal inclination of the saddle.

Hinges 9 also provide a transverse inclination of the saddle up to 3° and reduce the dynamic load on the frame of the vehicle-tractor from the semi-trailer. Under the base plate of the saddle there is a coupling mechanism, consisting of two grippers 12 mounted on axles 8, a locking fist 13 with a stem and a spring 14, a latch 15 with a spring 10, a release control handle and a safety bar. The locking fist 13 has two positions: rear - grips are closed and front - grips are open. Before coupling, the locking fist is moved to the “clamps open” position by the control lever and is held in this position by latch 15.

When the king pin enters the mouth of the jaws, they open. The fist, released from fixation by the latch, moves and locks the grips. In this case, under the action of the spring, the fist enters the grooves of the grips and the safety bar 1 automatically locks the fist rod. The fifth wheel couplings are lubricated through oilers 5 and 7.

Often, on a truck-tractor, in order to provide the necessary angles of longitudinal flexibility, the fifth wheel coupling is placed above the frame at a significant elevation. For this purpose, intermediate parts are installed between the bottom plate of the saddle and the frame of the tractor car: a wooden beam, a subframe and a stand.

The fifth wheel coupling device of KamAZ family tractor vehicles perceives a vertical load of not more than 130 kN. The saddle axles rotate in rubber-metal bushings, which can significantly reduce the dynamic loads transmitted by the semi-trailer to the frame of the tractor vehicle.

From the consideration of the design features of coupling devices, it is easy to conclude that the interlocking of saddle road trains is significantly limited compared to trailer road trains.

In articulated buses, to connect a two-axle tractor (front section of the bus) with a single-axle trailer (rear section of the bus), an articulation joint (Fig. 10) is used, consisting of a ball pin fixed in the base console of the front section of the bus, and a plastic sleeve installed in the base console trailer. Such a connection provides a turn of the trailer around the longitudinal axis by ±2°, the transverse axis by ±10° and around the vertical axis by ±42°.

The trailer control system receives a command signal from the front section of the bus through the articulation frame, the position of which must always remain on the bisector of the angle between the front section and the trailer. It is this kinematics that ensures the movement of the trailer wheels along the track of the wheels of the rear axle of the front section of the bus and, as a result, the minimum turning radius and good fit into road curves.

Management is provided by two adjustable steering rods and 3 front sections of the bus connected by a rocker arm 2 of the articulation frame. Tie rod 1 at one end is attached to the body of the front section of the bus, and the steering rod 3 is attached to the trailer body at the other end.

Trailer steering rods consist of three longitudinal rods 13, 11 and 5 intermediate levers 12 and 10 with brackets 9. The front longitudinal steering rod 13 of the trailer is connected to the base of the front section of the bus, and the rear longitudinal steering rod 5 of the trailer through the transverse steering rod 6 and bracket 7 , mounted on the trailer axle, is connected to the gear levers 8 and 4, which transmit movement to the wheels of the trailer axle. To ensure the free passage of passengers from the front to the rear section of the bus and back, a rotary disk consisting of two symmetrical half-sectors is installed in the joint of the front section of the bus with the trailer.

From: Vasiliev A.,