RU2016954C1 - Device for adjusting force in suspension bridge cable - Google Patents

Abstract

FIELD: civil engineering. SUBSTANCE: device comprises weight whose opposite sides have lugs. Said weight is fastened to cable guy and is located in well whose vertical wall are provided with guides for lugs in the form of flat sliding surfaces. The counteropposed sides of weight at location of lugs have niches while lugs have the form of a part of wheel installed in each niche on axle with journal. Guides are inclined towards vertical walls of well. EFFECT: improved design. 1 dwg

Description

 The invention relates to bridge and building structures. It can be used in the construction of suspension bridges and in suspension coatings of buildings.

 A disadvantage of the known device is that the pulling force created by it, largely depends on the sliding friction forces between the protrusions and the sliding surfaces. This reduces the stability of the device, since the sliding friction forces to a large extent depend on the state of the sliding surfaces.

 The aim of the invention is to drastically reduce the influence of sliding friction forces on the pull force.

 The goal is achieved due to the fact that the protrusions on the load are made so that each of them is a protruding part of the wheel, the other part of which is located in a niche arranged in the load.

 The drawing schematically shows the proposed device.

 The device for controlling the force in the cable of the suspension bridge includes a load 1 attached to the guy line 2, located in the well 3 and provided with protrusions 4 and 5 located on its opposite faces, which are the protruding part of the wheel, the other part of which is located in a niche arranged in the load. The protrusion 5 is below the protrusion 4, located on the verge of the load on the side where the horizontal component of the pulling force is directed.

 Flat surfaces on which protrusions - wheels abut, are located at an angle α to vertical planes - surfaces of opposing walls of the well.

 In the proposed device between the protrusions, which are part of the wheel, and flat surfaces tilted at an angle α to the vertical planes, there are not sliding friction forces, but rolling friction forces.

= f₀F (1), где К - коэффициент трения качения между выступом - колесом и наклоненной под углом α к вертикальной плоскости плоской поверхностью;
f - коэффициент трения цапфы оси колеса в подшипнике;
r - радиус цапфы оси колеса;
R - радиус колеса;
F - давление выступа - колеса на наклоненную под углом α к вертикальной плоскости плоскую поверхность, по которой колесо перекатывается.The resistance to rolling the protrusion - the wheel is
T = f

= f ₀ F (1), where K is the coefficient of rolling friction between the protrusion - the wheel and the flat surface inclined at an angle α to the vertical plane;
f is the coefficient of friction of the axle axle of the wheel in the bearing;
r is the radius of the axle of the wheel axis;
R is the radius of the wheel;
F is the pressure of the protrusion of the wheel on a flat surface inclined at an angle α to the vertical plane, on which the wheel rolls.

 From the formula (1) it can be seen that the rolling friction force in the proposed device has a much smaller value than the sliding friction force in the prototype device.

(2), где A=

;
Q - вес груза;
β - угол наклона оттяжки к горизонтали (см. чертеж);
С - расстояние между горизонтальными плоскостями, одна из которых проходит через точку, в которой оттяжка прикреплена к грузу, а другая - через ось цапф верхнего выступа - колеса;
h - расстояние между горизонтальными плоскостями, проходящими через оси цапф верхнего и нижнего выступов - колес;
f_o - коэффициент тяги, приведенный в формуле (1);
b - плечо силы трения качения (на чертеже не показано.The maximum force created by the proposed device in the guy is equal to
S _max =

(2) where A =

;
Q is the weight of the cargo;
β is the angle of inclination of the guy to the horizontal (see drawing);
C is the distance between horizontal planes, one of which passes through the point at which the guy line is attached to the load, and the other through the axis of the trunnions of the upper protrusion — the wheels;
h is the distance between the horizontal planes passing through the axles of the trunnions of the upper and lower protrusions - wheels;
f _o - thrust coefficient given in the formula (1);
b - shoulder of the rolling friction force (not shown in the drawing.

The distance from the axis of the load to the faces having protrusions - wheels, in the drawing are denoted by b ₁ (they are approximately equal to shoulder b).

 An analysis of formula (2) shows that with an increase in the angle α, the pulling force increases. At the same time, friction forces play a small role in creating a pulling force, which guarantees high stability of the device.

 The wheels, which are installed in cargo niches and act as protrusions, have an axle with pins. Their width should be sufficient to ensure the stability of the cargo. If you need a large width of the wheels, then you can use wheelsets.

 The use of the invention will increase the stability of the pulling force and the reliability of the device, ensuring a constant stress in the cable suspension bridge.

Claims (1)

 DEVICE FOR REGULATING THE EFFORT IN A CABLE OF A DANGEROUS BRIDGE, including a load having opposite projections on a cable, fastened in a cable guy and placed in a well, on the vertical walls of which there are guides in the form of flat sliding surfaces under the protrusions, characterized in that on opposite sides of the load in places the protrusions are formed niches, and the protrusions are made in the form of a part of the wheel mounted in each niche by means of an axis with a pin, while the guides are made inclined to vertical m to the walls of the well.

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