SU1650880A1 - Method of increasing load-bearing capacity of lattice boom of dragline - Google Patents

Description

 2648.75 kg;

v sl + + w

 2561.75 kg (see Fig, 3). The deflection angle of the rope in the final position in the section between the fixed posts of a constant height (Fig. 6) is

180 P 2R 180 3, 75

 - I - - ™ - I ". -

ft

3017Э4-6500

 3.7036 °.

The angle of deflection of the rope in the extreme sections (Fig. 6) is equal to

(X, arcsin (-sinoO. -2-2561.75 + 2,648.75 arcsin (b48775

sin 3.7036) arcsin 0.1895445 10.9262 °,

Tension in the rope is S,

1 (Xv 6500

- about G / / ((

cos 0 (

) QQ7Q1

% 99797G) 3017.4 20518 kg.

The value of the height of the additional support columns corresponds to

1 „, 65001P ooto °

h 7 tgO, 2 | - tg 10.9262

 313.7 cm

The stroke of the center post of variable length is equal to

A-Itgrf- tg 3.7036- 105.2 cm.

The height of the central pillar of changes ™ 55 in the final position (Figs. 1 and 6) is

h, h + D 313.7 + 105, 9 cm.

Maximum compressive stresses are

C 1§§0021205J 8

Max

s

 1604 kg / cm

2 x 65

0

five

0

five

0

five

five

0

where 2x65 130 cm is the total area of real people by Sov.

As can be seen from this example, using the proposed method to ensure favorable cycle asymmetry, one bottom rope is sufficient. At the same time, a favorable cycle asymmetry is created along the entire length of the carrier waves. In the case of using the known method with respect to this boom (i.e., a boom with a large span of 1 65 m) in the lower half of the center at a distance of 1/4 the length of the span from the center of the boom, the tensile stress is 111 Gy / kg.

In order to ensure that the asymmetry obtained in this place of the lower half (R0-0.29), using the known method, it is necessary to compensate for this stretch, increase the force in the tension rope (approximately, without taking into account cos 0) by

So 6p.2F 111x2x65 14430 kg.

At the same time, the upper c in this section was over-clamped, which weakened its local stability. Increasing the tension in the lower tensioning cable would require a reduction in the final deflection angle of the rope, since the force from the tensioning cable in the direction perpendicular to the boom axis (force that eliminates bending in mid-span) P 2 8 81p (Xc- for each particular boom with its weight characteristics, the value is constant. In turn, decreasing the final deflection angle of the rope leads to a decrease in the rigidity of the cable system and the boom is generally proportional to

rationally the squared deflection angle. Therefore, in the known method, in order to increase the final angle as much as possible (x and at the same time to carry out the necessary pressure, it is advisable to press the booms with two ropes - upper and lower.

Claims (1)

In the proposed method, for booms with large lengths, the necessary loop asymmetry can be achieved with a single rope. The mass of the boom, the implementation of the proposed method, is 47180 kg against 52300 kg of the base model. Invention Formula A method for increasing the carrying capacity of an excavator-dragline trellis boom, including the creation of a pre-tensioning lower cable 0 compressive stresses of a bearing by means of a force deflection of a rope with a support leg of variable length in the middle of the boom span, in order to reduce the metal intensity of the boom as its length increases by increasing the resistance to fatigue failure by eliminating bending mounts and deflections from the boom's own weight in at least three sections along the boom length while maintaining its reliability, level of rigidity and stability, the lower tension cable is supported by two additional hundred ki constant height set at a distance of one-fourth span length from the ends of the boom, which value is determined by the formula l - 1 h 4 t tg arcsin ( removing the sag of the rope, it is tentatively pulling it up to the longitudinal axis of the longitudinal axis in the region between the above-mentioned racks; 2P c7 1,180 7 tg TS 4 31 R (H + G force from the squeezing rope in the direction perpendicular to the axis of the boom, in racks of constant height, necessary to eliminate the bending moments in the boom at the places of installation of these racks; q - straight load uniformly distributed by the mass of the boom mass, taking into account 2P + P sin five 0  3-1 four five 0 five its angle of inclination to the horizon G - concentrated the load from the mass of additional racks, taking into account the angle of the boom; + G is the force realized from the twisting rope in the direction perpendicular to the axis of the boom, in the central rack of variable height, necessary to eliminate the bending moment from the mass of the boom in the middle of its span. C ,, is the axial stiffness of the tie rope; 1 - boom span length. Aa g s 72 FIG. 2 B-5 fie.Z P FIGA , FIG. five SK FIG. 6