What mechanisms are there for office chairs and how to use them.

How to insert the rollers into the base, why you need a gas lift cover or how to remove the gas lift. And in general, see how to assemble an office chair in the video section

The price of an office chair depends both on its external qualities and on its technical parameters. The upholstery of the chair greatly influences the price; it can be made of different materials, ranging from simple fabric to high-quality leather. But still, the “lion’s share” of the cost of the chair is its mechanism. Let's talk about him.

Different companies make different mechanisms for their chairs, but they are all similar. Let's start with the simplest one, which is used for inexpensive chairs.

"Piastra" and "Spring-screw mechanism"

Fig 1 - Piastra. Hole for gas lift (buy piastres). Fig 2 - Handle for adjusting the chair height.

Piastra is the simplest mechanism that works only up and down, by adjusting the handle where the gas lift valve is pressed. Installed mainly on cheap models of chairs.

This is what the piastre looks like from the bottom of the chair:

Catalog section:
All chairs with PIASTRE mechanism

Examples of chairs with a piastre mechanism:

Many inexpensive chairs also have a spring-screw mechanism for constant back support. There is a spring under the plastic “knob”. And when twisted, it contracts, imparting rigidity to the tilt of the back, or vice versa, making the tilt easier. (Fig. 3). It allows you to relieve your back a little.

In staff chairs, like the Prestige model, the spring-screw mechanism works differently. There are three screws, when tightened, it becomes possible to adjust the height of the backrest (red arrow), the deviation of the backrest (blue arrow) and the distance from the seat (green) (Fig. 4). But everywhere the work happens with the help of a spring.

Fig.3 Fig.4

Examples of chairs with a spring-screw mechanism:

"Jupiter" chairman 9801pl "Focus GTP"

Types of rocking mechanisms for computer chairs

According to statistics provided by various scientists, a person spends an average of 10 years of his entire life at a computer.
Of course, the most important attribute in computer work is a chair. Not only the health of the spine, but also the result of the work performed depends on comfort. Manufacturers of computer chairs try to create the most comfortable conditions for us, so they have come up with many mechanisms for an ideal fit.

Below we will look at what types of swinging computer chairs there are and their main properties.

Piastra

Behind the big name lies one of the first and simplest mechanisms. It is able to adjust the height of the chair and is an indispensable attribute for any user.

Multiblock

The adjustment mechanism is loved by many computer users and is very popular. And this is not at all surprising. This device has the most important functions - it not only adjusts the tilt of the chair back, it also

fixes it in various positions. Used primarily in computer chairs of more advanced models. Computer chairs with Multiblock are a little more expensive, but are more reliable and have more functionality.

Multiblock has several varieties.

• multiblock with offset axis. This mechanism is responsible for constant contact of the seated legs with the floor. The angle of the back of the chair does not play any role here.
• multiblock with asynchronous mechanism. A distinctive feature of this model is that when a person sitting in a chair rocks, the back of the chair rocks with him, but the seat does not change its position. This mechanism will allow you to relieve tension from your back without completely swaying.

TOP gun

This device allows you to rock the chair and gives you the opportunity to relax and unwind.

Most often, the top gun is found in office chairs and executive chairs. Using the lever, you can adjust the chair in height, rock it, or fix the position. The top gun is also equipped with a screw that adjusts the rigidity of the swing depending on the weight of the owner of the chair. Computer chairs with a Top Gun are easier to use and, as a rule, are not expensive. This mechanism is also used on more expensive models of gaming chairs.

Multi top gun

The mechanism differs from the classic top gun by the presence of another lever. Allows you to fix the chair in any convenient position.

Reinforced Top Gun

It is characterized by increased strength. This device is designed for heavy loads. Withstands weight up to 200 kg. Chairs with a Reinforced Top Gun are more massive and will be comfortable for large people.

Synchro mechanism

Proportionally adjusts the angle of the chair seat and its backrest. For this mechanism, the ideal proportion is 3:1, that is, for every 3 degrees of backrest tilt there is 1 degree of seat tilt.

We have listed the main mechanisms for rocking computer chairs. Now let's move on to the lesser known, but no less practical.

1. Permanent contact. Note that this variety also serves as an excellent creator of comfortable work. The main element of the mechanism is a tight spring, which allows the back of the chair to fit the back of the seated person, adjust its angle and fix it in a comfortable position. This mechanism has three main properties: the ability to adjust the height of the backrest, the angle of deflection and the seating depth.
2. The spring-screw mechanism is the simplest, but important invention. Adjusts the rigidity of the backrest swing. The mechanism is activated when the back is supported and tilts the back of the computer chair depending on the strength of the support.
3. The deep swing mechanism is a type of chair swing for big fans of special comfort. In general, the mechanism has something in common with the Top Gun, but its difference is the presence of an additional lever, which allows you to swing the chair more strongly.
4. Slider – allows you to fix the seat in 5 different positions.

"Centered swing mechanism" or "Top gun"

This mechanism comes on most director's chairs, and resembles a rocking chair, in the range of 95 - 135 degrees. When the chair is fully tilted, the seated person's legs come off the floor (because the tilt axis is in the middle of the chair and the upper edge rises when tilted), which is not a positive thing. In more expensive models, the axis is shifted closer to the edge. And this allows the legs to not rise up as much.

The mechanism that locks the chair in the working position (this means in a straight sitting position, without tilting) has three adjustments (Fig. 5). 1. The chair is adjusted up and down using a lever that acts on the gas lift. 2. The same lever, when adjusted to the right or left, allows you to “turn on the swing mechanism” or fix the chair in the working position (i.e. with a straight back). 3. (Tilt Tension) The spring allows you to adjust the rigidity of the swing. It is very convenient to adjust to your weight, making the swing more rigid for heavy people, or less rigid for lighter people.

In Figure 6, you can see this mechanism on the chair. The devices are quite bulky, which does not allow them to be installed on operator chairs (such chairs have their own mechanism, which is smaller in size).

Fig.5 Fig.6

Top Gun mechanism (buy swing mechanism)

Catalog section:

All chairs with TOPGAN mechanism

This is what the topgan looks like from below:

Examples of chairs with a top gun swing mechanism:

Other options for swing mechanisms

All of the above mechanisms have proven themselves in terms of reliability, ease of control and comfort. However, manufacturers are constantly developing new designs to please the most demanding customers:

Deep Tilt (Knee mechanism)

Recommended for connoisseurs of swinging with increased amplitude. Its device is similar to DMSL - two levers, an adjustment screw, the ability to fix the tilt of the computer chair in the desired position. It is characterized by increased reliability, therefore suitable for massive models with a metal frame.

Multiblock synchro (Synchromesh mechanism)

– an advanced design installed on gaming, orthopedic and premium chairs. The main difference from a conventional multiblock is that the backrest tilts more than the seat (in a ratio of 2:1 or 3:1). As a result, the feet do not come off the floor, and the edge of the seat does not pinch the legs under the knees. Control is carried out in the same way as in a multiblock.

Inexpensive office chairs for staff and visitors use a piastra - a gas lift control knob to change the height of the seat. The combination of piastres + permanent contact provides a little more comfort - an elastic spring presses the back of the chair against the person’s back, deviating slightly if necessary. You can adjust the rigidity of the tilt, seat depth and back height.

The final choice of swing mechanism depends on your budget and personal wishes for comfort level.

Chair rocking mechanisms

1. Piastra is a device that allows you to adjust the chair exclusively in height. Up down. And that is all.

It is a block with a gas lift control lever, which, in turn, has the magical power to raise and lower your chair. Typically used in low-cost operator models.

2. Permanent contact.

Along with piastres, you can often find permanent contact in a chair. It is based on an elastic spring, which allows the back of the chair to press against the back of the person sitting and, accordingly, regulates its angle and fixation.

it has 3 adjustments:

• back height
• planting depth
• backrest deflection rigidity

3. PVM (spring-screw mechanism) - another device for connecting the seat and back of the chair.

It has only 1 adjustment: backrest swing stiffness. The interesting thing is that the backrest here is not fixed in any position - initially it is vertical. But when you lean on it, the front actuator is activated, and the backrest tilts depending on your contact force (or weight).

4. Top gun

The top gun, or centered swing mechanism, or DMS is a “rocker”. Such devices are used in executive chairs.

The top gun has three adjustments:

1. Up and down, using a lever that acts on the gas lift and raises or lowers the chair.
2. The same lever, if adjusted not up and down, but right and left, activates the swing mechanism, or, conversely, fixes the chair in the working position.
3. The mechanism contains an adjusting screw, which allows you to adjust the rigidity of the swing depending on the weight of the person sitting.

The mechanism is called “centered” because its axis is located in the middle of the chair, which means that when the chair is fully tilted, the seated person’s feet are lifted off the floor. In more expensive models (which have a multiblock with an offset axis, which we will talk about later), the swing axis is shifted closer to the edge , and therefore it is more comfortable to swing: your feet are on the ground.

5. Multiblock

The good old and beloved chair transformation mechanism . It has all the top gun adjustments, and what's more:

• Allows you to adjust the force of deflection of the chair during swinging and its rigidity
• Fixes the chair back in several positions (up to 5 positions)

Multiblock with an offset axis is a variation of the multiblock that ensures constant contact of the feet with the floor, no matter what the tilt of the chair is at this moment. Such a mechanism can be found in ergonomic, comfortable models of executive chairs.

Multiblock with synchro mechanism

The synchro mechanism changes the angle of inclination of both the back of the chair and the seat separately, but all at the same time. In other words, when rocking, the seat and backrest move separately from each other, but in a certain proportion to the angle of inclination. As a rule, the optimal proportion is a ratio of 3:1. Backrest tilt 3 degrees = seat tilt 1 degree. The tilt range of the chair back is 30-36 degrees. At the same time, any synchronizing mechanism is necessarily equipped with load adjustment for personal adjustment to your weight in order to ensure maximum unloading of the spine.

Multiblock with asynchronous mechanism

The asynchronous mechanism performs exactly the same functions as the synchronous mechanism, but at the same time the back and seat tilt independently of each other, following the movement vector of the seated body. In other words, when you rock on a chair, the backrest swings with you, but the seat remains fixed in one position. Or vice versa.

What other additional mechanisms exist in nature? In addition to the above, the chairs may contain: Multi top gun, or luxury top gun, or DMSL - this is a more advanced version of the top gun from the point above. The difference from the basic top-gun mechanism is the presence of a lever for fixing the chair in any convenient position. Actually, this is what makes it “luxury”. “Anti-shock effect” is a mechanism that independently smoothly returns the chair to its working position after unlocking. This means that you do not receive a sharp push in the back from your favorite (or no longer?) chair, but calmly return to your working position. A slider is a device that regulates the depth of the seat (it can “move” back and forth and lock in 5 different positions, moving the back of the chair further away or closer to you).

Oh, this piastra, or what you should pay attention to when choosing a computer chair

General considerations. Rhetorical questions And here it is, a “painfully” familiar chair. The vast majority of people began their table life with something similar. Yes, this version of computer chairs is widespread and in most cases many offices are equipped with such chairs and we can’t get away from them anywhere.

At the same time, there are those who would not exchange this version of the chair for anything or anything. As a colleague said: “When there is a lot to do, you don’t really think about what to sit on, you need to work.” In addition, when it’s not particularly comfortable to sit, you tend to “toss and turn” more often, and this is a kind of warm-up. Others will say about the expression “to the point of pain” that we are not talking about any figurative meaning. The seat is small, it pinches your legs, they swell and that’s why you want to put them on the cross. It’s not for us to judge, everyone has their own choice. Therefore, we will not develop the topic in this direction and go into details of what hurts and why, but let’s move on to the main thing: we will discuss how the Chairman 668 computer chair worth 9,450 rubles differs from the above-mentioned one, which costs 2.5-3 times cheaper. Most likely, your employer/director/boss has a different chair than yours. And therefore the thought may torment you: is the more expensive “director’s” chair better than mine? Is it worth going to the management with a request (or demand) to replace the chair, having at hand a list of reasons, such as: my productivity will increase, I will spend the night in this chair at work, etc., and convince why you personally need to change the computer chair or sit quietly on your own, but without additional obligations. So, go or wait?

What does “piastra” have to do with the title? Let me explain. The fact is that a piastra is a device/mechanism, the main unit with which the chair is controlled, and quite often it is the reason for the chair’s failure. Therefore, it is important to take care of the piastrum, and the simplest thing is not to “plop” into the chair as quickly as possible. This action will save you from looking for a welder you know!

By the way, it’s possible that the chairs are not a piastre, but a more complex and interesting device, but it is worth emphasizing that this does not make the mechanism stronger, so being careful when using it will not hurt. These devices, unlike piastres, have different names and have a certain set of functions. – “TOP GAN” swing mechanism, which, in addition to lifting up/down, allows the backrest and seat to tilt back up to 135 degrees (if the initial position is 90) and fix the backrest in two positions. – The multiblock is a more improved swing mechanism that allows you to fix the seat and backrest in up to 5 positions/positions. – Synchronous mechanism/asynchronous mechanism - where either the seat and backrest angle change synchronously and the most optimal ratio is selected, or the seat and backrest do not depend on each other, so the angle of inclination can be selected independently. – Anti-shock effect is a function in which the backrest does not hit you on the back after the swing lock is removed, but smoothly returns the backrest. – A multiblock with an offset axis allows your feet to always remain on the floor at any angle of the chair and does not require you to look for an additional item for a footrest. Considering the above, and not taking into account the design, upholstery material, filling, body material and other little things, the chairs cost more than tens or even hundreds of thousands of rubles. What mechanism is used in the chair being tested - Chairman 668? Of course, this is a gas lift, which is controlled by a lever. Let's not dwell on it, it works as usual. “TOP GAN” swing mechanism with the possibility of synchronous (simultaneous) fixation of the backrest and chair in two positions, namely, in working and maximally reclined. There is also a spring mechanism with which you can independently adjust the swing rigidity, taking into account your weight. The chair can be adjusted in such a way that reclining the chair back occurs from a slight touch on the backrest to the point where considerable effort is required. Therefore, the choice is up to the person sitting. For comparison, “lying down” would be 180 degrees, so 135 degrees is enough to “digest lunch” within 5-10 minutes.

Isn't this enough? What about other effects? In principle, if a person comes to the office to work and not to relax, then this is quite enough.
The spring mechanism will create the necessary elasticity of the backrest, and the rocking mechanism is capable of fixing the chair in a vertical position, although a small backlash remains (it’s difficult to say for sure whether this is good or bad, depending on who you choose). And if after lunch you can lean back, stretch and pamper yourself, then fixing the chair in the most reclined state will be of great help to you. By the way, if you have a habit of “dangling” your legs during sleep, then fixation creates confidence that you will not be lifted back and returned to your original position without your knowledge. Therefore, the conclusion suggests itself - the mechanism used in the Chairman 668 chair not only satisfies the needs of the sitter, but also makes them comfortable. Some explanations on these characteristics. Overhang : 660 mm. This means from the edge of the seat to the edge of the backrest (two extreme points). If the distance is limited, then it is important to take this parameter into account. Depth : 560 mm. The size indicated is from the edge of the seat to the main backrest (say, the frame), and if you measure from the edge of the seat to the pillow-cover with an additional layer of foam rubber, which is on the backrest, then it turns out to be 500 mm. Knowing this size and how you like to sit - pressed against the back or not - you can understand which seat protrusion will be optimal for you. If you like to sit pressed against the back, then it is important to calculate in advance what is the distance of your leg to the popliteal part. If it is less than the specified distance of the seat itself (500 mm), then it will not be possible to sit with your back pressed against the backrest. By the way, there is a very nice protrusion on the edge of the seat. Pay attention to this.

Back height : 1090 mm - 1170 mm. We are talking about the size from the floor to the top of the backrest at the minimum lowering and maximum raising of the chair. The chair does not have a mechanism for adjusting the backrest height - Up&Down; the backrest does not rise or fall separately from the seat. Knowing this, what might these dimensions mean in real life? If a person with a height of 172 cm presses close to the back, then the lower part of the back of the head lies exactly on the edge of the back. Perhaps there may be a feeling that the backrest could be higher so that the whole head rests on the backrest, but... in order to sleep comfortably, a bed would not hurt. Upholstery material : eco leather. One of the questions that arises is: “Isn’t it hot in it?” There is no definite answer, because the comfortable temperature is different for everyone. Compared to the “textile” material, there is a feeling of greater warmth, but you cannot say that you are sitting “wet”. Armrests : in the tested chair they are filled with foam rubber and upholstered in eco-leather. If you sit in a T-shirt or short-sleeve shirt, then apparently this is not an unimportant point that is worth paying attention to. Some people enjoy touching cold things, while others hate it. Package dimensions : 660x760x380. In reality it looks like this.

What about all the above mechanisms? Just a money grab? Of course not. All mechanisms and every “trick” are additional amenities, but you have to pay for them. Some mechanisms have already been described above. Here's another one. For example, using a mechanism called “Slider” you can adjust and fix the depth of the seat, and this is sometimes important if the proportions of the body are such that the back of the thigh is short. If the seat depth is 500 mm, then accordingly the size from the popliteal recess to the place slightly below the lower back should be no less than this.

Information for those who read the instructions after something went wrong.

The instructions not only write, but also clearly show what to do with the cap, which is put on the Gaslift during transportation and only performs a protective function. If you do not remove it and install the chair on the gas lift along with the cap, then the gas lift will not work. And due to the fact that the chair is put on with effort, it is very difficult to get the cap later. The cap is that extra part that quite often remains after assembly!

Those who read the instructions at the beginning and like to compare everything are invited to find the differences... On the left side is the tested chair, and on the right is a similar one, but cheaper by about 2,600 rubles.

The table shows the main differences: armrests and material/design of the crosspiece. It turns out that design and strength are what costs extra money. And finding out the differences turned out to be not so difficult. All you had to do was either call the store or order a call back, and this was clearly presented on the seller’s website. We think you shouldn’t miss this opportunity and find out everything that interests you before purchasing!

Results. Subjective opinion. In comparison with a “regular” chair, the conclusion suggests itself. It seems that it is not worth commenting on. Most of the colleagues who came to look at the chair said “Wow!” and someone even compared a “regular” chair with a chair on wheels and a small back support. Indeed, this is a very soft and pleasant chair for work and relaxation. We will see how the chair stands the test of time and hope that we will have the opportunity to compare other samples.

The chair was provided by the Mebelion.ru store