Desk

Desk
The main parameters that define the compliance desks growth of the child: 1 - height converted to student sides of the cover; 2 - seat height; 3 - differentiation; 4 - negative distance; 5 - the distance back; turn of the cover; 7 - seat depth.

The Desk - type of school furniture. The design and dimensions of the desks should provide the student a comfortable working position, which is of importance for prevention of General fatigue, prevent violations of posture and protection of view. The size of the individual elements desks are determined by the proportions of the body of students. The height of the bench is the length of the lower leg with his foot. Its depth is equal to 2/3 length of the thigh. Seat desks must be hard, shaped in the form of the hip, or even, with a slope towards the back by 3-5 degrees. As an additional support bench has the back of two rods with the angle of inclination of 7-12 degrees and in subscapularis region. In order to create optimal conditions for vision cover the Desk has a slope of 12-15 degrees. The connection table and benches is based differencie and distances of the seat and backrest. The difference is the distance between the edge of the cover desks, addressed to the student, and the plane of the seat vertically. Each room desks corresponds to a certain differentiation (distance seats) - the distance between the edge of the cover facing the disciple, and the front edge of the bench horizontally (Fig.).
When writing the most convenient negative distance of 4-5 cm, and the positive and zero is invalid. Using the folding of the cover the distance becomes positive that allows the student is free to stand up or sit down at the Desk. The distance back - the distance between the most raised part of the backrest of the bench and the edge of the cover desks, addressed to the student.
Depending on the growth of the students developed 7 rooms desks (from # 6 to # 12). Students with a difference growth in 10 cm maintain the correct position of the body at the Desk of the same size.
The desks are made in accordance with all-Union State standard (GOST 5994-64) single and double stationary (with a constant size) and universal (with varying height of a table and a chair).
On the side of the Desk are marked in a fraction, the numerator of which is the number of desks, and the denominator is it appropriate growth group.
The Desk should be lightweight, strong, carefully decorated. External furnish is executed in light colours layered plastic, lacquer or enamel is resistant to washing with warm water and soap and disinfectants application.

The Desk is a type of school furniture. From the correct device desks and compliance of its elements the body proportions and growth of students depends on the correct landing schoolchildren and prevention of violations of the normal view (Fig.).
Hatchback cover the desks should be such that it housed freely book and notebook at an angle of 25 degrees to the edge of the lid of the Desk. In order schoolboy was able to get up, the table cover P. folding is done.
At the correct device desks connection table., and a bench (or chair) allows you to lean back against the bench (chair). This reduces the fatigue of students and is one of the important means to prevent spinal curvature.
The depth of the bench P. (front-back dimensions of its seats) should be equal to 2/3-3/4 the length of the thigh student. At greater depths seat blood vessels and nerves popliteal region schoolboy will be squeezed by, at least it will be difficult to maintain a steady landing and he inevitably will move out from the bench (chair). Seat height of the bench (chair) must match the length of the lower leg (to popliteal depression) student + 2 cm with the height of the heel). In larger seat height feet will hang and he will move out from the bench (chair). If the seat height is less, the leg at the knee and hip joints will be bent at a sharp angle that will cause obstruction of blood flow in lower limbs. The bar backless benches should be at the level of the lumbar spine curve and have a section coinciding with the curve.
The correct connection of the table, desks and benches depends on the correct choice of the distance back, seat and differencie desks. Distance backrest is the distance from the edge of the lid of the Desk, facing towards the student back to Petrograd; it should not exceed the diameter of the trunk of a pupil on 3-5 see At a greater distance back from the edge of the cover schoolboy during reading and writing have to move forward on the seat, in the student gets tired quickly; trying to avoid fatigue, he takes the wrong posture, leading to the breakdown of view, and to spinal curvature. With a too small value of distance back schoolboy is compressed between the edge of the cover P. and seat, which leads to the constraint of movement. Distance seat Isthmus is the distance from the edge of the lid of the Desk, facing the student, to the front edge of the seat horizontally. It is of three types: positive, neutral and negative. Negative distance seat desks is where the front edge of the seat comes za-3 cm over the edge of the lid of the Desk, facing the student. It is most meet hygienic requirements, as it provides the student the most convenient, least tedious and right fit for P. when reading and writing.
The difference P. is the distance from the edge of the lid of the Desk, facing a schoolboy, to seat bench vertically, in other words, the difference represents the difference between the height of the cover of the table and seat height., In a properly built parte differentiation should exceed the distance from the seat to the elbow of the hand pressed to the body to 2-2 .5 cm With less differencie student is forced to bend over the table, which leads to difficulty in breathing, irregular land behind P. and fatigue. If the difference P. exceeds the set value, for example at high table and a low seat, the student must constantly be raised his right shoulder, which leads to the curvature of the spine. The same Desk can be used by students, the growth of which ranges from 10 see In this connection are installed P. different sizes, in accordance with the increase of students from the 6th to the 12th rooms inclusive (see table).
To paint P. recommended matte paints of bright colors, which increases the overall lightness of the classroom and helps to inculcate students hygienic skills and accuracy.