The hilt of the crane is embedded in the nut moving along the screw g. The latter is moved in motion with a steel cable, wrapping the pulley and then passing through two guide pulleys. The cable bypasses sequentially all the jacking installations, and its ends are stuck into opposite-
PROSELASE OF JEAMS AND the order of their work. The rise of the building requires the simultaneous use of a large number of jacks. In buildings with brick load -bearing walls, a large number of jacks are used with relatively small lifting force (from 5 to 20 tons).
For buildings with iron and reinforced concrete columns as concentrating large loads in individual reference points, it is possible to use a smaller number of jacks, but with a larger lifting force (up to 100 tons).
With vertical movements on the cells, it is required if you do not use the jacks of the perpetuum, a doubled number of jacks.
Examples of American practice show that the ratio of the total lifting force of all installed jacks to the weight of the building reaches a size of 3.5 to 10 and only in some cases decreases to 2.
The arrangement of jacks for elements of the frame that supports the genes is made at distances between centers from 25 cm to 1 m.
With a significant number of lifting devices, their maintenance becomes quite difficult. It is usually carried out by the arrangement of workers at the rate of one person for 15 – 20 jacks. The twisting of the latter is twisted on a predetermined insignificant amount of rise of 2 – 3 mm (a quarter of the screw turnover) and is carried out simultaneously by all workers on the sound signal given by the manager. Each of the workers at one reception of lifting passes its own group “Fats there and back,
Lri uneven rise of the building (precipitation) for each of the jacks, a special, respectively calculated lifting height is prescribed, for which divisions indicate the required angles of rotation of the handle installed on each jack of the board.
The position of the plane of the cut. The plane on which the building is cut, most often is prescribed directly below the ceilings of the basement or in the absence of one below the floor of the first floor.
