It is false to give an exact definition of what an office chair is. However, it is possible to identify individual features that fit this definition. First of all, an office chair is best suited for long periods of sitting at a computer.
No matter how comfortable a soft sofa is, even a standard 9-hour working day on it exhausts your back muscles. And its long-term use as a workplace can even lead to spinal diseases.
The design of office chairs has long been thought out by engineers. Their design allows you to correctly distribute the weight and position of the body so that the person does not get tired and the back does not hurt. This effect is achieved by certain design features.
Types of office chairs
- For a manager, as a rule, such models are larger and more expensive than others, since they should not only serve as a convenient workplace, but also show the status of the owner. Leather and natural wood are often used in design. The most convenient and reliable.
- For staff - the most common chairs. They are often simply called computer chairs. Inexpensive, but no less convenient. They also prevent your back from getting tired during long periods of working at the computer. Often purchased for home use.
- Ergonomic - a separate direction of chairs that have additional options for adjusting the backrest, seat, headrest and armrests.
- Gaming chairs are another popular trend in chairs in recent years. Gamers, like office workers, spend a lot of time at the computer, so manufacturers began to produce models with a bright design that resembles the seat of a sports car.
Two more types of chairs are also office chairs, but have a simpler design, so they do not need a detailed description:
- For visitors - a simplified version of office chairs without swing, rotation and height adjustment mechanisms. They have regular legs. They are often purchased in bulk for waiting rooms.
- Conference chairs - the main difference is that these chairs are connected in several pieces. Many models have an additional table so that conference visitors or lecture participants can take down information.
Despite the large number of varieties, all chairs have common design features.
Cross with wheels
The foundation that holds the entire chair is a five-pointed cross with wheels.
Its size is determined by the size and functionality of the chair itself. In large models with the ability to lean back and turn the chair into a full-fledged chaise lounge, a larger crosspiece is needed. In smaller, simpler models you can save a little on the size of the cross. However, not so much that the chair could tip over.
The crosspiece itself is made of durable metal so that the chair can withstand heavy weight. Sometimes it is simply chromed or painted. Sometimes plastic or wood linings are installed on top. This only affects appearance.
The wheels are the most movable part of the chair; they bear the entire load, so they are most often prone to breakdowns. Manufacturers know this, so they most often provide for the possibility of easy replacement.
Repairing the chair cross
Repairing the crosspiece of an office chair with your own hands is quite possible with some mechanical skills. To do this you will need simple tools and attentiveness.
The material of the crosspiece is important - if it is made of plastic, then it is better to install a new one. Plastic after repair serves even worse than new and restoring such a fragile part makes little sense. Pay attention to the type of plastic; it is better to replace the polyethylene cross with glass filled polyamide because this material is stronger and lasts longer than conventional plastics.
Disconnect the cross from the chair
To repair the crosspiece, you need to remove it and this process is not as simple as it seems. This often damages the part itself and the gas lift, especially if you use a hammer or sledgehammer. Be sure to use rollers because they are often damaged during disassembly and repair. Tool required:
- Hammer
- Kiyanka
- Screwdriver
It is better to cover the floor with rags or newspapers to protect it from grease. To disassemble tight connections, especially a gas cartridge with a cross, it is convenient to use WD-40, gasoline, or just soapy water. Attention! You can knock down a cross with a hammer only if it is metal; for a plastic one, you need to use a mallet. We recommend watching a video of an office chair repair.
Gas lift
The mechanism responsible for shock absorption, rotation and the ability to adjust height. It is a steel cylinder filled with inert gas.
Compound:
- valve opening and closing button;
- gas valve;
- bushings and seals;
- 2 cavities. External and internal;
- passageway;
- Lifting rod;
- support bearing.
Operating principle.
In simple terms, by pulling the lever, you open the bypass valve. Gas from the outer cylinder begins to fill the space of the inner cylinder. There, the gas presses against the piston, creating pressure that causes the chair to rise. By pulling the lever while sitting on the chair, the gas passes from the inner cylinder to the outer one, thus lowering it.
Back
Ensures correct back position. May vary in height. Be straight or made in an anatomical S shape, simulating the correct position of the spine.
Depending on the design, the backrest may be attached to the seat and not be adjusted in any way relative to it. In such cases, it has an angle of slightly more than 90 degrees relative to the seat.
This allows you to relieve excess stress on the spine. The swing mechanism in such models allows the backrest to recline along with the seat. In more advanced models, the backrest reclines more than the seat, turning the chair into a chaise lounge.
In chairs where the backrest is fixed separately from the seat, it is possible to adjust its height, angle of inclination and sometimes depth.
What is a gas lift for an office chair?
A gas lift or gas cartridge is a mechanism that is responsible for adjusting the height of the seat surface and allows you to fix it in a position convenient for use.
The main elements of the gas cartridge: cylinder and spindle.
To ensure that your device serves you for many years, we recommend following these steps:
- - do not jump on the chair;
- - once every few months, lubricate the elements of the chair with special oil;
- - under no circumstances should you sit in a chair together and create an advantage;
Causes of gas cartridge failure:
- — not careful handling of the office chair;
- — the user’s weight exceeds the permissible weight for operation;
- — the warranty period has expired;
- — the user sits on the chair from a jump;
- - rocking in a chair when the mechanism is in a fixed position.
If your chair's warranty period has expired and a breakdown occurs, then having certain knowledge, you can make repairs at home.
If you sit down on a chair, and it independently changes the position of the seat down, and after a while returns to its place, this is one of the signs of a breakdown of the gas cartridge. In this situation, you can fix the position of the chair using improvised means or replace the gas lift.
In order to replace the gas cartridge, you will need:
- - armchair;
- - screwdriver;
- - rubber hammer;
- - metal drift;
- — a new gas cartridge, suitable in diameter and length;
- - vice.
Progress:
- -If you carry out repairs in the cold season, the liquid in the gas cartridge may freeze; it is prohibited to use it. You must wait until the new gas lift reaches room temperature.
- — Next, use a shaped screwdriver to unscrew the seat from the piastres.
- — Turn the chair over and make a mark on the face of the rocking unit.
- — Then unscrew the four screws that secure the chair with the rocking mechanism.
- — Now we dismantle the protective casing.
- — using a rubber hammer, tap the swing mechanism at the base of the gas lift with gentle blows.
- - now knock the gas cartridge out of the crosspiece.
- - then turn the crosspiece over with the rollers up, and using a metal drift, delivering precise blows, knock out the gas cartridge from the cone base of the crosspiece.
Now you have to do the reverse process - assembly:
- — We screw the swing mechanism to the backrest seat.
- — Then place the crosspiece with its wheels on the floor, and then remove the transport cap from the new gas cartridge.
- Important: do not press the gas cartridge button in your hands, this is dangerous to your health!
- — now we are installing a new gas lift, make sure that the diameter of the gas cartridge completely coincides with the cross.
- — now we put on the protective cover, and then the chair body on the swing mechanism.
- — we press our hands on the body of the chair, check all the elements and sit down in the chair to check the operation of the new gas cartridge.
Helpful Tips:
- - if you have assembled a new chair, and you immediately have problems with the gas cartridge. There is a high probability that the gas lift is in poor condition or defective. But it is also possible that the gas cartridge button can be fixed with a lever from the swing mechanism.
- - if the gas lift does not respond when you press the lever, make sure that the piastres or the swing system are secured correctly, as well as the integrity of the lever for pressing the button.
If the above reasons are absent, the gas lift needs to be replaced.
Mechanisms
After the gas lift, the most technologically advanced part of office chairs is the adjustment and swing mechanisms.
Piastra
The simplest mechanism is with a lever that presses the gas lift valve. Allows you to adjust the chair only in height. Sometimes it is supplemented with a simple mechanism that allows you to adjust the depth of the seat by moving the backrest.
Basic spring mechanisms
A spring hidden under a plastic cover allows you to adjust the backrest tilt. Models with such mechanisms also have the ability to adjust the backrest in height and depth.
Top Gun (Centered Swing Mechanism)
Most executive chairs are equipped with this mechanism. Allows the chair to recline in the range from 95 to 135 degrees. However, since the mechanism is centered, the seat also tilts, which forces the feet to leave the floor. This is the main disadvantage of such a mechanism. In expensive models, this is solved by shifting the axis to the edge.
Multiblock (Complex mechanisms with tilt fixation)
Multiblocks or synchronized mechanisms are placed on ergonomic chairs. They automatically change the angle of the backrest depending on the weight of the person. This provides the spine with maximum comfort.
In addition, the mechanism allows you to fix the backrest in a comfortable position.
Product disassembly stages
If an office chair breaks, the first thing you need to do is disassemble the structure. To do this, you will need a rubber hammer, slotted and Phillips screwdrivers, and a ring drift. All actions are carried out in stages:
- First of all, remove the seat, turn the chair over, and remove the fasteners.
- Unscrew the bolts that secure the armrests and remove these parts along with the plates.
- Disconnect the fasteners holding the permanent contact.
- The crosspiece is separated from the pneumatic chuck by gently tapping the connection with a hammer.
- The wheels are removed from the mounting sockets, and the plugs located in the steel case are removed. The procedure is performed using a slotted screwdriver.
Popular Ikea chair-beds - design and design features
It is recommended to carry out all manipulations with the mechanisms while holding the structure suspended so as not to break the fragile plastic parts. For the same reason, you should not use physical force when unscrewing fasteners. After completing the dismantling of the computer chair, you need to collect all the parts in one place so as not to lose anything.
Armrests and headrests
Armrests provide elbow support if needed. If you are sitting at a comfortable desk and do not need additional arm support, the armrests can be detached. However, in some models of executive chairs, the backrest is attached to the seat precisely through the armrests, so they perform not only a decorative function, but also a constructive one.
Armrests are made of plastic, metal and wood. The material depends on the design and price.
In ergonomic models, the armrests can be adjusted in height.
The headrest is not a mandatory element, so most chairs do not have one or it is part of the backrest. However, ergonomic chairs allow you to adjust not only the height of the headrest, but also the depth.
Common breakdowns
As noted above, an office chair is a rather complex device and any of its structural elements can fail.
Damage to the cross
The problem with this element may be destruction at the junction of the beams. The material from which the cross is made is important here.
As a rule, the base is a hollow structure into which a polypropylene pipe of suitable size and cross-section can be inserted. It, in turn, must be rigidly fixed to the base and the damaged beam.
Plastic parts cannot be spliced using glue or a soldering iron due to the large loads on the paws. There is no point in restoring the integrity of this element. The best option would be to completely replace the damaged structure with a glass-filled polyamide base.
In order to dismantle the crosspiece of an office chair, you need:
- Remove rollers. As a rule, they do not have a rigid fixation and are quite simply removed from the mounting sockets. To illustrate the process, it is recommended to watch the video:
- Dismantle the piastra. Fastening to the seat is done “on a cone”. Disconnection from the gas elevator is carried out by tapping on the attachment point. The correct process for disassembling an office chair is shown in the video:
- Remove the locking clip located in the recess on the top of the hydraulic lift.
- Knock out the gas lift for repair or replacement of the five-beam.
Note! In case of critical damage or destruction, it is impossible to knock the gas elevator out of the base. In this case, you should remove the working cylinder with the seal and bearing from the “glass”.
The process technology and dismantling device are shown in the video:
Destruction of the swing mechanism
If the chair does not hold the “horizon”, then the problem is most likely in the destruction of the swing mechanism.
Fastening to the seat is done with four screws using a shaped screwdriver. The element is dismantled as follows:
- The bolts that secure the rocking mechanism from the seat are unscrewed
- The gas lift is knocked out of the device mount.
This element is made of metal.
You can independently solve the problem of a collapsed device by completely replacing it (recommended) or using a welding machine.
It should be noted that most chairs originating from the Middle Kingdom are not suitable for domestic spare parts. This concerns, first of all, the swing mechanisms (size discrepancy).
- Chinese mechanisms: 200 x 200 mm.
- Domestic: 200 x 150 mm.
In order not to re-drill holes when replacing an element, we suggest using adapter plates. How it looks assembled can be seen in the figure below.
Air chuck failure
The pneumatic cartridge of the chair is a two-chamber structure filled with air. When you press the adjustment lever, the valve stops the flow of air between the chambers.
If, when pressing on the valve, the gas lift rod does not extend, it means that the integrity of the piston, seal, etc. is compromised.
It is important to know! The gas lift cannot be disassembled . If damaged, a complete replacement of the element is required
The dismantling process is described above. To clarify the process, watch the video about replacing the gas cartridge on office chairs:
A fairly common cause of gas lift failure is the bending of the adjustment lever, which does not allow pressing on the cartridge valve. In this case, the repair can be easily carried out independently: you need to bend the lever to its original state.
