Max. user weight
The highest weight that the chair is guaranteed to withstand with regular use — in other words,
the maximum weight of a seated person, allowing you to constantly use the product in normal mode without fear of unexpected breakdown. Note that many models are able to endure short-term excess weight without problems, however, anyway, it is not worth overloading the structure (and even more so doing it all the time): off-design loads will significantly increase its wear, and breakdown can occur at the most unexpected moment.
Seat height
Seat height from the floor. The optimal height for a person of average height is considered to be 40 – 50 cm, however, this moment is largely subjective, and the comfort of the chair for a particular user depends heavily on his preferences and physique. Thus, many models have the ability to change the height in a certain range (see "Adjustments"). To choose, it is best to determine “live” at what height you are comfortable sitting, and find a model with the appropriate characteristics.
Mechanism
A type of mechanism that provides various adjustments (see below).
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Permanent contact. A mechanism designed to ensure constant contact between the back of the seated person and the back of the chair. Accordingly, the adjustments available when using it relate only to the back, but the list of such adjustments is quite extensive: in height, inclination and depth of the back. At the same time, permanent contact is found mainly in inexpensive chair models.
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Freestyle. Also known as a permanent back support mechanism. Another fairly simple option, concerning only the adjustment of the back of the chair. The back and seat in such models are connected by a flexible plastic cover, which contains a spring; due to a special screw, it is possible to change the degree of compression of the spring, thus adjusting the degree of swing stiffness.
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Tilt(swing). Also known as Top Gun. A mechanism that provides the possibility of rocking back and forth, as well as adjusting the rocking stiffness; in addition, in most cases it also provides the adjustment of the seat height according to the principle of the piastres described above. The adjustment knob is responsible for two functions — gas lift control and swing blocking; rocking stiffness is usually controlled separately. This type of mechanism involves a rigidly connected back and seat.
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...href="/list/897/pr-28623/">Deep Tilt(deep swing). A variation of the tilt mechanism (see the relevant paragraph), which, in accordance with the name, provides the possibility of a deeper swing. Simply put, in such a chair you can lean back very far, almost lie down. However the seat and backrest in such models are still rigidly connected to each other, and fixation is provided only in one position — vertical (working).
This option is typical mainly for products of the middle and higher price range.
— Freelock. Like the Tilt described above, this mechanism allows free swing and stiffness adjustment. In such chairs, however, fixation in one position is not provided — on the other hand, the backrest in them does not have a rigid connection with the seat and can be separately adjusted in height and inclination.
— Multiblock. In fact, it is an improved and supplemented version of the Tilt described above. Multiblocks not only allow you to swing and adjust the rigidity of the swing, but also provide the possibility of fixing the chair in four positions (instead of one). In addition, they are usually equipped with so-called “anti-shock effect”: when unlocking, the tilt of the chair does not change on its own, for this you need to apply a little effort. This prevents jerks and shocks to the occupant's body when the mounts are released.
— AnyFix. A kind of swing mechanism that allows you to fix the chair in any intermediate position — and not only in those specified by the manufacturer, as is the case with Tilt and multiblocks (see above). Provides maximum freedom in tilt adjustment, however, it is quite expensive.
— MultiFix. Another, along with AnyFix, is a kind of tilt mechanism that allows you to fix the chair in any intermediate position. In fact, from the point of view of the user, these mechanisms fundamentally differ only in name. Accordingly, the advantages and disadvantages of "multifixes" are the same: on the one hand, this is convenience in setting up, on the other hand, a higher cost than, for example, "tilts". Also note that the seat and back in such chairs are usually rigidly connected and lean together.
— Synchro mechanism. The name of this mechanism is due to the fact that the back and seat in it are synchronized in a special way: when swinging, they do not deviate in the same way, but in a ratio of 2:1. It is believed that this provides an anatomically optimal fit to the position of the human body when bending back. In addition, such mechanisms usually have several fixed tilt positions, rocking stiffness settings and an anti-shock system (described in detail in the “Multiblock” paragraph above). This option is considered one of the most suitable for high-quality "director's" chairs (see "Purpose").
— Asynchronous. The asynchronous mechanism assumes the presence of a back and a seat that can change the slope independently of each other; usually, both there and there several fixed provisions are provided. Such designs provide ample features for customization to individual preferences, but the customization itself is not as convenient as in most of the advanced mechanisms described above.
— Piastre. One of the simplest mechanisms, found mainly in low-cost-level models. Allows you to change only the height of the seat. The operation of the mechanism is based on the action of a gas lift — a sealed reservoir with a piston, where gas is pumped under high pressure. The gas lift is located in the support column of the chair, under the seat, and the handle is usually located on the side of this column, within reach of the person sitting, for adjustment. Pressing this knob unlocks the seat and you can adjust the chair as you wish – raise it up and let the gas lift push the seat up, or push it down and lower the height. When the handle is released, the seat is fixed in the predetermined position. Gas lifts are often used in conjunction with other options described below, and the “piastre” type includes only structures that do not have other mechanisms for adjustment — these are mainly low-cost-class chairs.
— React. Mechanism developed by Legett&Platt; React's specific feature is that it combines the rocking of the back with the movement of the seat back and forth. This, according to the creators, provides the most comfortable and at the same time natural movement of the body when swinging. Another interesting feature is that React does not require manual adjustment to the user's weight, the mechanism itself regulates the effort required for swinging. There are usually as many as 8 fixed positions. Armchairs with such a mechanism may outwardly resemble models for staff (see "Purpose") — in particular, they have a back and seat clearly separated from each other — however, with all its advantages, React is not cheap, as a result of which Still, it's more for leaders.
– Relaxing Active System. Another high-end "anatomical" movement, designed for the most comfortable and natural movement; used mainly in furniture from the company Elano. Like the React described above, it combines the swing of the back with the movement of the seat back and forth; in addition, it may also be possible to change the inclination of the headrest depending on the inclination of the backrest. At the same time, chairs with the Relaxing Active System are usually made in a solid classic design, using leather, which makes them look rich and representative, but they also cost accordingly.
— Aircraft. A variation of the rocking mechanism used primarily in AMF chairs. In chairs with this feature, the place of attachment of the seat to the stand is not located in the centre of the seat, but closer to the front edge, at the very knees. This is believed to provide additional comfort and a more natural body position than traditional binding arrangements. Otherwise, this mechanism is similar to the Tilt systems (see above).
— Double springs. A mechanism based on a twin spring that supports the back of the chair and creates impedance when the seated person leans back. The impedance of the springs can be adjusted, thus changing the angle by which the backrest will deflect under the weight of the user. This mechanism is used in some gaming chairs (see "Purpose").
