RU2034773C1 - Boom crane with turntable - Google Patents

Abstract

FIELD: materials handling facilities. SUBSTANCE: boom crane has hook load, boom radius and angle indicators, maximum overturning moment setter and tolerable loads comparison circuit. Signal processing circuit provides for correcting crane load characteristic from ideal to real one. EFFECT: increased reliability and safety of operation. 2 dwg

Description

 The invention relates to hoisting and transport engineering and is intended for trouble-free transshipment of cargo by jib cranes.

 A jib crane with a rotary platform is known, comprising a load sensor on the hook, a boom length sensor, a boom angle sensor, a task unit for the threshold value of the overturning moment of the crane and a comparison circuit connected by its output to the actuator prohibiting the operation of the crane and connected to the load sensor by its inputs on the hook and through a signal processing circuit with boom length and tilt sensors and a task unit for the threshold value of the tipping moment.

 A disadvantage of the known crane is the complexity of the mathematical model for determining the allowable load on the hook from the equation of the static equilibrium of the crane, since the initial information must be obtained by measurements carried out directly on the crane. Another disadvantage is the non-universality of the mathematical model used, since the equation of static equilibrium is not the only condition that must be taken into account when assigning the cargo characteristics of the crane. Such conditions include the bearing capacity of the main metal structures of the crane, the bearing capacity of the rope, slewing ring and some other design considerations. Taking these factors into account significantly complicates the mathematical model for determining the permissible load on the hook and, accordingly, the design of the crane.

 The aim of the invention is to simplify the design and increase its versatility, ensuring trouble-free operation with any of its modifications with a rotary platform by continuously monitoring the load characteristics when changing the length of the boom and load on the hook within the specified limits.

· M где В величина поправки длины плеча опрокидывания крана, м;
L текущее значение вылета стрелы относительно оси вращения поворотной платформы, м;
L_стр текущее значение длины стрелы, м;
М переводной коэффициент, равный 1 м²;
а, b, и с размерные коэффициенты, удовлетворяющие условию решения неравенства
(-L_min) < (a + bL_cтр + cL² _стр) < L_min;
L_min минимальный вылет стрелы относительно оси вращения поворотной платформы, м,
а блок вычисления допустимой нагрузки на крюке с учетом вылета стрелы выполнен с возможностью вычисления им указанной нагрузки по выражению
Q

ΔQ где Q допустимая нагрузка на крюке с учетом вылета стрелы, т;
К пороговая величина опрокидывающего момента крана, т˙м;
L текущее значение вылета стрелы относительно оси вращения поворотной платформы, м;
А расстояние от оси вращения поворотной платформы до ребра опрокидывания, м;
В величина поправки длины плеча опрокидывания крана, м;
Δ Q масса конструкций крана, приведенная к оголовку стрелы, т.This goal is achieved by the fact that in the well-known crane the signal processing circuit consists of a block for determining the boom extension relative to the axis of the turntable connected to the outputs of the boom length sensor and the boom tilt sensor, and the unit for calculating the length of the tipping arm of the crane connected with one of its inputs to the output of the boom length sensor, and the other to the output of the boom extension determination unit, the unit for calculating the maximum load on the hook depending on the length of the boom connected to the output by its input at the boom length sensor, and with its output to the first input of the comparison circuit, the hook load allowance calculation unit taking into account the boom extension, connected with its first input to the output of the boom departure determination unit, the second input to the output of the unit for calculating the length of the crane tipping shoulder length adjustment and the third the input to the output of the task block of the threshold value of the overturning moment of the crane, and its output connected to the second input of the comparison circuit, while the load sensor on the hook is connected directly by its output to t the input of the comparison circuit, the unit for calculating the magnitude of the correction of the length of the shoulder of the tipping crane is made with the possibility of calculating the specified correction by expression
B

· M where In the magnitude of the correction of the length of the shoulder tipping crane, m;
L current value of the boom departure relative to the axis of rotation of the turntable, m;
L _{p the} current value of the length of the boom, m;
M conversion factor equal to 1 m ² ;
a, b, and c are dimensional coefficients satisfying the condition for solving the inequality
(-L _min ) <(a + bL _page + cL ² _page ) <L _min ;
L _{min the} minimum reach of the boom relative to the axis of rotation of the turntable, m,
and the unit for calculating the permissible load on the hook, taking into account the boom extension, is configured to calculate the specified load by the expression
Q

ΔQ where Q is the permissible load on the hook, taking into account the outreach, t;
K threshold value of the tipping moment of the crane, t˙m;
L current value of the boom departure relative to the axis of rotation of the turntable, m;
And the distance from the axis of rotation of the turntable to the tipping ribs, m;
In the magnitude of the correction of the length of the shoulder tipping crane, m;
Δ Q is the mass of crane structures reduced to the boom head, t.

 In FIG. 1 shows a General view of the crane with an indication of its parameters; in FIG. 2 is a block diagram of the limitation of its carrying capacity.

 The jib crane with a rotary platform comprises a hook load sensor 1, an arrow length sensor 2, an arrow tilt sensor 3, a crane tilting moment threshold task unit 4, a boom overhang detection unit 5 relative to the rotary platform, connected by its inputs to the outputs of the 2 length sensors, and 3 boom tilt angles, block 6 for calculating the value of adjusting the length of the overturning arm of the crane, connected by one input to the output of the sensor 2 of the length of the boom, and the other to the output of block 5 for determining the boom extension, block 7 for calculating unit load on the hook depending on the length of the boom, connected by its input to the output of the sensor 2 of the length of the boom, block 8 calculating the maximum load on the hook taking into account the boom, connected by its first input to the output of block 5, the second input to the output of block 6, and the third the input to the output of block 4, the comparison circuit 9, connected with its first input to the output of block 7, the second input to the output of block 8 and the third input directly to the output of the load sensor 1 on the hook, the actuator 10 for inhibiting the operation of the crane is connected with its input to you go comparison circuit 9. Blocks 5-8 comprise a signal processing circuit.

 Jib crane with a rotary platform works as follows.

The boom of the crane extends to the required length for work and lifts the load suspended on the hook. The sensor 1 receives the load on the crane hook from the mass to be lifted and transmits a signal on the magnitude of this load to the third input of the comparison circuit 9. Block 4 sets the threshold value of the tipping moment of the crane. This value depends on the geometric parameters and masses of the elements of a particular crane design. From sensors 2 and 3, signals about current values of length L _p and boom angle, respectively, are sent to block 5. Block 5 determines the current value of the outreach L of the boom relative to the axis of rotation of the turntable, namely: the length of the projection of the boom on the horizontal plane minus the horizontal distance N from the rotational axis of the turntable to the axis of the boom hinge on the turntable. The signal about the current value of the departure L of the boom from the output of block 5 is transmitted to the second and first inputs of blocks 6 and 8, respectively. To the first input of block 6, a signal is output from the output of sensor 2 from the current value of the length of the boom L _p . When developing cranes, as a rule, the ideal cargo characteristic of the crane is accepted according to the condition of static equilibrium
K (Q + Δ Q) (LA), where K is the threshold value of the overturning moment, t˙m;
Q permissible load on the hook, t;
L current boom reach, m;
A distance from the axis of rotation of the turntable to the tipping ribs, m;
Δ Q is the mass of crane structures reduced to the boom head, t.

· M, м где В величина поправки длины плеча опрокидывания плеча крана, м;
L текущее значение вылета стрелы относительно оси вращения поворотной платформы, м;
fL_стр функция, зависящая от длины стрелы, которая легко аппроксимируется прямой линией или кривой второго порядка;
L_стр текущее значение длины стрелы, м.However, in practice, the actual cargo characteristic is somewhat different from ideal. The invention allows the adjustment of the ideal characteristics of the crane and to bring it as close as possible to the real one by introducing the correction value to the length of the tipping arm of the crane (LA). This correction is calculated by block 6, which, receiving signals about the current values of the length and reach of the boom, calculates the correction to the length of the tipping arm according to the expression
B

· M, m where In the value of the correction of the length of the shoulder tipping over the shoulder of the crane, m;
L current value of the boom departure relative to the axis of rotation of the turntable, m;
fL _page function depending on the arm length, which can be easily approximated by a straight line or a curve of second order;
L _{p the} current value of the length of the boom, m

· M где М переводной коэффициент, равный 1 м².In general, the function fL _p can be represented as a + bL _p + cL _p , and the dimensional coefficients are easily found, solving the inequalities
(-L _min ) <(a + bL _p + cL ² _p ) <L _min ; where L _{min is the} minimum outreach relative to the axis of rotation of the turntable (m), the value is constant, determined by the particular construction of the crane. Thus, block 6 calculates the correction value of the length of the tipping shoulder according to the expression
B

· M where M is a conversion factor of 1 m ² .

ΔQ где К пороговая величина опрокидывающего момента, т˙м;
L текущее значение вылета стрелы, м;
A расстояние от оси вращения поворотной платформы до ребра опрокидывания, м;
В величина поправки длины плеча опрокидывания крана, м;
Δ Q масса конструкций крана, приведенная к оголовку стрелы, т.The signal about the correction value of the tipping length is transmitted from block 6 to the second input of block 8. The signal of block 4 about the threshold value of the tipping moment K is transmitted to the third input of block 8. Block 8, based on the signals received at its inputs, calculates the allowable load on the hook taking into account the departure boom and tilt shoulder length corrections according to the formula
Q _add =

ΔQ where K is the threshold value of the overturning moment, t˙m;
L is the current value of the boom, m;
A distance from the axis of rotation of the turntable to the tipping ribs, m;
In the magnitude of the correction of the length of the shoulder tipping crane, m;
Δ Q is the mass of crane structures reduced to the boom head, t.

 From block 8, a signal about the size of the permissible load on the hook, taking into account the boom, adjusted already according to the actual load characteristic, is fed to the second input of the comparison circuit 9. Block 7 receives a signal about the current value of the length of the boom from the sensor 2 and calculates the maximum load on the hook depending on the length of the boom. According to the crane's load characteristic, each boom length corresponds to a specific defined value of the maximum load on the hook. The third input of the comparison circuit 9 receives a signal from the sensor 1 about the value of the real load on the hook. In scheme 9, the signals from the sensor 1 about the actual load on the hook are compared with the signal from block 7 about the maximum load on the hook depending on the length of the boom and with the signal from block 8 about the permissible load on the hook, taking into account the outreach of the arrow. If the actual load on the hook exceeds the maximum load or the permissible load, the circuit 9 gives a signal to the actuator 10 to prohibit the operation of the crane.

 Compared with the prototype, the proposed crane can improve the safety of work by adjusting the cargo characteristics of the crane. The scheme for limiting its carrying capacity is simple, universal for any crane model, it does not require the use of switches when switching from one working characteristic to another when changing the length of the boom, type of working equipment, it is reliable in operation, which improves the operational characteristics of the crane.

Claims (1)

ARROW CRANE WITH A ROTARY PLATFORM, containing a load sensor on the hook, an arrow length sensor, an angle sensor, a task unit for the threshold value of the overturning moment of the crane and a comparison circuit connected by an output to the actuator prohibiting the operation of the crane, and the inputs connected to the load sensor on the hook and through a signal processing circuit with boom length and tilt sensors and a task unit for the threshold value of the tipping moment of the crane, characterized in that the signal processing circuit consists of a determination unit in boom range relative to the axis of rotation of the turntable connected by inputs to the outputs of the boom length sensor and boom tilt sensor, a unit for calculating the length of the overturning arm of the crane connected by one input to the output of the boom length sensor, and the other to the output of the boom extension determination unit, the limit calculation unit load on the hook, depending on the length of the boom connected to the output of the sensor for the length of the boom, and the output to the first input of the comparison circuit, the unit for calculating the permissible load on the hook taking into account ohm of the boom extension connected by the first input to the output of the boom extension determination unit, by the second input to the output of the unit for calculating the value of the crane tipping shoulder length adjustment and the third input to the output of the task unit of the threshold value of the tipping moment of the crane, and the output of the comparison circuit connected to the second input, while the load sensor on the hook is connected directly by the output to the third input of the comparison circuit, the unit for calculating the correction value of the length of the overturning arm of the crane is configured to calculate th amendment on expression

where B is the correction value of the length of the shoulder of the tipping crane, m;
L current value of the boom departure relative to the axis of rotation of the turntable, m;
L _{with t r the} current value of the length of the boom, m;
M is a conversion factor equal to 1, m ² ;
a, b, and c are dimensional coefficients satisfying the condition for solving the inequality
(-L _min ) <(a + bL _p + cL $\genfrac{}{}{0ex}{}{\text{2}}{\text{with}}$ _mp ) <L _min ,
where L _{m i n the} minimum reach of the boom relative to the axis of rotation of the turntable, m,
and the unit for calculating the permissible load on the hook, taking into account the boom extension, is configured to calculate the specified load by the expression

where Q _{d about p} permissible load on the hook, taking into account the boom, t;
K is the threshold value of the tipping moment of the crane, taking into account the mass of the crane structures, reduced to the head of the boom, t · m;
L current value of the boom departure relative to the axis of rotation of the turntable, m;
A distance from the axis of rotation of the turntable to the tipping ribs, m;
B value of the correction of the length of the shoulder tipping crane, m;
ΔQ is the mass of crane structures reduced to the boom head, t.

Images