Safety cage. Bolted and welded car frame

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

While watching videos and photos of sports cars, you can see one important feature - these are the pipes located in the cabin. They intersect with each other, and the driver of the car is, as it were, in a cage. It is nothing more than a safety cage. People far from motorsport may not know what it is. So, let's take a closer look at what this framework is for.

What is this?

These pipes are a special spatial structure, the main task of which is to prevent significant deformations in the event of various traffic situations. The roll cage should protect the body in the event of a collision or vehicle overturn.

This is a kind of steel structure made of pipes, assembled using welded or bolted joints. In the cabin, this design is attached to the body from all sides. The goal is not only to save the body of the car from damage, but also to save the lives of the driver and navigator of the car in the event of a serious accident. Also thesesolutions are used to strengthen the longitudinal rigidity of the body.

In civilian cars, it is quite difficult to see the roll cage. They were used on rally cars, but then this design became the main condition for other sports racing disciplines. This system was assembled mainly from round pipes, as they are the least dangerous for the crew.

Types of frames

These designs can be collapsible or non-collapsible. By the way, the cost fluctuation in different variations can be very wide - from a thousand dollars for a simple option to tens of thousands for more complex ones.

Collapsible design

This is a safety cage installed inside the car. It is fixed on the side pillars of the body, as well as on the floor. Each of the pipes that enters the frame is connected by bolted connections. The advantage of this solution is that at any time the cage can be easily dismantled and the once-sporty VAZ body becomes completely civilian. I must say that these are simple systems and anyone can handle dismantling. There are no special requirements for such a solution. There is no maximum level of rigidity here, it is possible to keep the salon plastic.

Welded frames

Welded options are already more complex in terms of engineering. Here the frame is connected with the power and structural features of the body. The welded version is used when serious, and most importantly, individual tuning is needed. Installation will take much longerhard work. For implementation, you need to completely disassemble the entire interior down to the metal. Then make mounting and technical holes for mounting the frame. Further, the entire structure is connected to each other, and after that it is all welded.

The requirements for such a safety cage are more serious. The design can be made for different types of bodies. Moreover, if the car is two-door, then the rigidity will be greater. It must be remembered that in the case of installation of complex options, the car will be designed for only two seats. The reason for this is that the place under the rear seats will be occupied by mounts, as well as intertwined pipes.

If you start from the overall dimensions, it becomes clear that the installation of a safety cage has other limitations. This is primarily an overview. For greater safety, special belts are attached to the frame pipes.

The safety cage and the law

Those who decide to install such a design need to remember and be prepared for problems with passing inspection. Required certification. The operation of such cars in cities is prohibited. The law says that you can only drive a car with a frame while wearing a helmet. But here there is a small detail - you can’t ride in the city in a helmet either.

Production Features

These solutions are predominantly produced from cold drawn steel pipe. In some cases, the use of aluminum is relevant. Practice shows that for maximum rigidity and efficiency, the pipeshould be in the following dimensions: length - 400-450 millimeters, and diameter - 20-25.

The weight of the structure for the VAZ body will be about forty kilograms. The mass of more serious decisions directly depends on the complexity of the framework. The metal pipe is painted in fairly bright colors. On some pipes included in the design, protection is installed. This is not for aesthetics, but for safety.

Homologated and non-homologated frame

Companies and workshops involved in the creation of such carcasses do not always take into account the technical standards of the FIA in their work. But at the same time, the product is regularly homologated. This is the coordination of design features, materials, manufacturing and assembly methods with the FIA or the automobile sports federation in the country.

So, if a manufacturer suddenly decides to use materials in their product that do not meet the properties of the FIA requirements list, then this decision must then be subjected to a load test. The design must be tested under pressure. Appropriate calculations of strength characteristics according to certain methods must also be submitted.

Another feature is the installation of a safety cage on a VAZ or other models. If it is decided to mount the structure by welding, then homologation is required. It often happens that carcass manufacturers do not fully take into account the schemes from the FIA. This will also require homologation. In this case, the use of non-homologated solutions is allowed. In thissituation, the frame is made of specific pipes, the material of which is a specific steel for a specific design. The pipes themselves have certain given overall dimensions. The safety cage is attached to the UAZ using bolts. One company may produce two variants of products, but on the condition that both designs comply with the schemes and specifications of the FIA.

Frame and handling

The main characteristic of the strength of car bodies is rigidity. If the body is not rigid enough, then the reaction to the steering wheel will become chaotic. The body is beaten, and the steel in the suspension arms resonates with the vehicle's axles. When twisting, the material wears out faster, metal fatigue increases. If you mount a safety cage on the VAZ-2108, then the body will no longer perform its supporting function. The entire load will go to the frame and be evenly distributed over it. The car will become more collected, and the reaction to the steering wheel will increase.

Assembling the frame with your own hands

Assembling a safety cage with your own hands is not too easy. It is not enough to have the skills to work with a welding machine and have the material. It is necessary to carry out certain calculations. You will also need drawings. If the car is not going to be raced, then prefabricated bolt-on construction will suffice - there are plenty of ready-made options on the market. It is better to select schemes carefully, and if you make a welded structure, then it is better to have the opportunity to consult with specialists. It is better not to take on welded solutions - here the calculations are even more complex, there are many formulas, a lot of nuances are taken into account.

But nothing is impossible. Of course, creating a serious structure that significantly increases rigidity is unlikely to work in a garage. But it is quite possible to weld arcs on UAZ with your own hands. You just need to decide on the diameter of the pipes and the sticking points.

So we figured out what a roll cage is.