What mechanisms are there for Office chairs: which one to choose

The pricing policy for office furniture is directly related to external qualities and technical components.

Computer chairs are an integral part of any office and almost every home.

The use of simple fabric or expensive leather upholstery significantly affects the cost of the chair, but the mechanisms are also of great importance.

The upholstery can be made of different materials, ranging from simple fabric to high-quality leather.

If you are faced with the question of choosing a chair for an office or home office, carefully study the technical characteristics of a particular mechanism, depending also on how long you will be in this chair every day.

Statistics show that the average person spends about 80 thousand hours in a sitting position in their life.

Choosing a chair

When planning to buy a chair for your workplace, you should carefully study the swing mechanism.

Every person wants to sit correctly and comfortably.

This feature was invented to create maximum comfort for a person who spends a lot of time in a sitting position.

When buying a chair, “try” it yourself: if it’s comfortable, feel free to take it.

To avoid negative consequences such as poor circulation, spinal problems and others, it is necessary to pay attention to how the chair can adapt to the individual characteristics of the human body, providing it with comfort.

A person’s well-being and performance will directly depend on the stool.

Rotation mechanisms should be oriented towards the ergonomics of the human body position.

It is also important to choose a chair to your liking. So that it matches your ambitions and is perfectly displayed in your image in your personal account.

The most common breakdowns of office chairs

Damage to the cross

The main damage to this element is a breakdown at the junction of the beams. It is important to consider the material it is made of. The base is a hollow structure, inside of which you can place a polypropylene pipe of suitable cross-section and dimensions. The pipe is rigidly fixed to the damaged beam and base.

Note! You cannot splice plastic elements using a soldering iron or glue due to the high load on the paws.

The best option is to replace the plastic structure with a base made of glass-filled polyamide.

Disassembling an office chair is not difficult.

Dismantling the cross is carried out as follows:

Removing rollers. Usually they are not rigidly secured.
Dismantling the piastres. The fastening to the seat is carried out “on a cone”. It is necessary to disconnect the piastrum from the pneumatic cartridge by tapping at the attachment point.
Removing the retaining clip. It is located in the recess of the upper segment of the gas lift.
Knocking out the gas lift. If the damage is serious enough, this will not work. In this case, the working cylinder is removed along with the bearing and seal.

The convenience and ease of setting up office furniture directly affects the work efficiency of those who use this furniture.

Destruction of the swing mechanism

If it breaks, the chair stops holding the “horizon”. Dismantling this element is quite simple:

Unscrew the four mounting screws.
Knock the air cartridge out of the mount.

During movement, a proportional unloading of the entire spine occurs along its length.
The preferred solution to the problem is to completely replace the part. You can use a welding machine to repair an old mechanism.

Note! Russian and Chinese standard mechanisms differ in size.

Gas lift failure

If the integrity of the pneumatic cartridge elements is damaged, the rod does not extend when pressed. In this case, a complete replacement of the entire mechanism is necessary. It cannot be disassembled due to gas pressure.

Also, quite often the cause of breakdown is the bending of the adjustment lever, which just needs to be bent and returned to its original state.

Gas lift breakdowns occur for several reasons.

The design of a computer chair is quite complex, and at the same time extremely thoughtful. This ensures maximum comfort during use and allows you to work for a long time in a sitting position.

Piastra

This mechanism is the most basic; it is installed on inexpensive models of mass-produced computer chairs. The plate is a lever block that controls the position of the gas lift. The plate performs one function: it fixes the height of the office chair. The plate controlled gas lift is the supporting element and connects the beam cross member to the seat base. Under the action of the lever, the piston stroke in the gas lift is turned on and the user adjusts the convenient position of the product.

The main advantages of the device are simplicity, reliability and low cost. But there is a limit: an office chair with a plate mechanism is suitable for those who intend to use the selected furniture no more than 3 hours a day. If you spend more than 3 hours in a work chair, you should take a closer look at more advanced mechanisms with adjustable backrest angle.

What to look for when choosing

Chairs of any type are selected taking into account their ergonomics.

It is important that the back of the product can be installed in a position that is comfortable for the human body. The best option for the back is chairs with a bolster for the spinal deflection.

When buying a rocking chair, you need to consider how much time you will have to spend in it. If the chair is used periodically, then you can opt for inexpensive models. For constant long-term sitting in a chair, it is better to choose more expensive models. A comfortable fit will increase work productivity and cause less harm to health.

Basic spring mechanisms

Quite often, in addition to the plate, the model is equipped with a spring back adjustment mechanism. A popular option with essential functionality is the Constant Contact Device, which supports the spine and reduces the stress of sitting in one place for many hours. The mechanism is designed in such a way that an elastic spring ensures contact between the back of the chair and the user's back. In addition to the ability to lean back without damaging the structure, constant contact ensures moderate oscillation of the backrest. This feature helps relax stiff back muscles and straighten legs that are tired from inactivity.

Constant contact regulates the depth of the seat in the chair, the height and degree of flexion of the back. Advantages of the mechanism:

suitable for people of any height and build;
the working spring is hidden in a durable plastic case;
simplicity of the device guarantees long life;
in the event of a breakdown, the permanent contact can be easily replaced with a new one without spending money on buying new furniture.

On budget models, the rigidity of the backrest swing is adjusted by a spring-screw mechanism, abbreviated as FDA or PVM. Changing the angle of the backrest is ensured by a spring hidden in a plastic housing. As a result, the backrest constantly supports the spine of the seated person and swings within a small radius.

How to set up the swing mechanism

The first thing to do is determine the rigidity of the swing. This parameter depends on the weight of the sitting person. If the computer chair was purchased for a child, the spring must be loosened. If we are talking about a chair for an adult weighing 90 kilograms, then it needs to be turned to the maximum.

Algorithm for setting the rotation mechanism:

Find the spring responsible for the swing of the structure. As a rule, it is located in the front of the chair under a plastic cover.
To adjust, turn the knob clockwise or counterclockwise, periodically checking the optimal firmness for the person sitting.

If the spring is fully rotated, no force is required to rotate it. Otherwise, the thread on the central bolt may break and the rotation mechanism will fail.

Some chairs have a different structure. Instead of a spring and a round handle, they are equipped with two levers (right and left). The first is responsible for raising and lowering the seat. The second is for the rigidity of the swing.

Top gun and Deep Tilt: office rocking chairs

The centered tilt mechanism (aka DMS) is installed on comfortable and solid models of office clothing furniture. If you choose furniture yourself and can spend a little more on personal comfort, we recommend that you take a closer look at models with a top cannon device. A rocking chair with VHI is good for health and mood:

the load on the intervertebral discs is reduced;
swing - simple prevention of disorders in the spine and back;
when rocking, stiff joints are warmed up, which improves the general condition of the body;
swings calm your nerves and help you concentrate.

Compared to the described permanent contact and PVM designs, the top gun has greater customization options:

height adjustment of the chair—the plate is no longer needed;
Turn the top lever of the gun to the left or right, and you can fix the position of the chair or activate the rocking mode;
Using the adjusting screw, the rigidity of the swing is adjusted taking into account the user’s weight.

The axis of the centered rocker mechanism is located directly in the center of the chair. Leaning back as far as possible, you lift your feet off the floor. A more convenient option is a multiblock with an offset axis: when swinging, your feet touch the floor.

An improved alternative to the top gun design is the Deep Tilt mechanism. Its functionality is the same as the DMS, but deeper rotation is possible thanks to a special lever. The chair can be locked in the working position. The advantage of Deep Tilt is its high degree of reliability. Install the Deep Tilt design on expensive and prestigious furniture models.

Question answer

Models of rocking chairs remove excess load from a person’s spine while working at a computer. This is a good prevention of various back diseases.

The multi-top gun swing mechanisms are considered the most reliable and comfortable. They allow you to change the position of both the seats and the backrest in the chairs.

One lever is used to raise and lower the structure, and the second is used to fix the swing angle.

The best option for such use would be a chair with a multi-top gun type swing mechanism.

The most common swing mechanism is DMS. Its axis is located in the center of the chair and provides a tilt angle of up to 130 degrees.

Office rocking chairs can relieve unnecessary stress from a person’s spine during work. They have ergonomic designs and are equipped with swing mechanisms. For permanent sedentary work of more than 4 hours a day, the use of chairs of this type is mandatory. They will help prevent the development of various back diseases.

Multiblock and its varieties

The multi-block design has a complex design and excellent functionality. Available system settings:

furniture height adjustment;
setting the backrest flexion rigidity;
the ability to fix your back in one of 5 (or more) positions in the range of 0-135 degrees;
download without restrictions;
anti-shock - protection against sudden impacts and chair tipping. In case of danger, the backrest gently returns the occupant to the working position.

The advantage of the multiblock is that it can easily support the user’s weight up to 120 kg. If the seated person weighs less, this feature automatically extends the life of the product at the expense of lower cost options. The standard multiblock has several options with improved characteristics:

The multiblock with a synchronized mechanism simultaneously adjusts the tilt of the backrest and seat of the chair in a ratio of 3: 1. When the backrest tilt angle increased by 30 degrees, the seat tilted by 10 degrees;
The multiblock with an asynchronous mechanism adjusts the tilt of the backrest and seat independently of each other. When the occupant turns the seat back, the seat remains in its original position;
a multiblock with an offset axis is an analogue of the top gun, which was already mentioned above. The axis is shifted forward towards the knees, which increases the comfort of the design. It allows you to swing without taking your feet off the floor.

Types of mechanisms and their operating principles

There are many mechanisms for office chairs, but the most common are the following:

Plate. This spring-loaded screw mechanism only allows you to adjust the seat height. It is a block with a gas lift control lever that provides height changes.
Constant contact. The most common mechanism that provides fixation of the back and its deviation at an angle of up to 128 °, which allows you to relax your back. It is also responsible for adjusting the firmness and depth of the seat.
Oscillatory mechanism. This allows the design to be used on the principle of a rocking chair, with the range of seat and backrest tilting from 95o to 135o. The rotation axis can be located in the central part or moved forward.

The plate is a lever block that controls the position of the gas lift.
Note! Rocking chairs are not recommended for people weighing more than 100 kg, as the welded sleeve used may break under high loads.
Shockproof effect. This mechanism makes it easy to return the chair to its working position after rocking. To do this, first the swing mode is blocked, then the backrest is pressed.
Synchromesh mechanism. It allows the sitting person to freely change position, triggers the swing mechanism, supports the back and prevents tipping over. This is achieved by changing the angle of the seat simultaneously with the tilt of the backrest.
Note! The most comfortable gear ratio is from 1 to 3, that is, the seat bends one degree when the backrest tilts three degrees.

If the chair does not hold the “horizon”, the problem is most likely the destruction of the swing mechanism.
Asynchronous mechanism. Allows you to change the backrest angle without reference to the seat position.
Slider. Allows you to adjust the depth of the seat, which extends forward with the ability to lock in different positions.

An asynchronous mechanism, unlike a synchronous one, allows you to change the backrest tilt without changing the position of the seat.

What parameters are adjustable?

To adjust an office chair, you need to change or adjust its parameters:

The highest point of the seat should barely reach knee level in a standing position or be slightly lower. It is also adjustable in relation to the level of the tabletop. When a person is sitting and his hands are on the table, his elbows should be bent at an angle of 90 degrees.
Backrest tilt. It is necessary to fix it at such an angle as to maintain the most comfortable position for the back of the person sitting. The chair should not rest against the spine, or, conversely, lean far back.
Rocking mechanism. This parameter is adjusted to the person’s weight. The larger it is, the more rigid the swing must be to avoid falling.
The height and angle of the armrests should be at such a level that the elbows of the person sitting in a bent position barely touch their surface. Otherwise, excessive pressure will be applied to the fingers and supporting parts of the hands.

To determine the correct body position in an office chair, you need to follow three simple rules. Firstly, it is recommended to place the center of the computer monitor directly at eye level: in order to read the necessary information from the screen, there should be no need to move your neck. Secondly, you need to feel good support for the curve of your lower back. Thirdly, the distance from the back of the shin to the front edge of the seat should be no more than 5 cm. To check this, just clench your fist and see how freely it passes between them. If the fist squeezes through with difficulty or does not fit at all, then the backrest needs to be moved forward. If the distance between the shins and the edge of the chair is too large, then it is moved back.