DE2140779C3 - Device for determining the limit loads on jib cranes - Google Patents

Description

The invention relates to a voting device the limit loads of jib cranes, in which the jib is successively in predetermined, Positions differentiated according to angle and length are brought and in the individual positions is exposed to an adjustable load in each case, whereby the load contact point of the load rope «Jer movement the boom can be tracked.

It is important to assess the load limit of a completed crane for a number of reasons germinate. The determination of the actual limit load is particularly important for calibration and programming of overload protection for jib cranes, which are programmed with pre-programmed »shutdown curves · ' work and switch off when the boom is supported by a permissible for the relevant outreach Load exceeding load is claimed.

It is difficult to determine the exact load limit of a crane based on the manufacturer's specifications Load curves and theoretical calculations, as the boom is dependent on the projection and the greetings of the load hanging on it sags (so-called "whip effect"). on The reason for this deflection of the boom is at a fixed angle and / or at a fixed length of the boom, the overhang is greater than with the unattended boom and the associated The crane's limit capacity is correspondingly smaller. If you look at the theoretical load curve on the basis of the adjustment or the programming of overload safety devices, one lies "On the insecure side".

A device of the type described at the beginning is already known (German Offenlegungsschrift 1 756 844), in which the load on the boom can be swiveled by moving a weight on one stored bar is changeable. The load rope grips over a trolley that can be moved along the beam on the bar. The desired test load is set using the movable weight.

Then the beam is raised by operating the crane's hoist. The pivoting of the bar? should then give an indication of the extent to which the overload protection of the crane is readjusted

That the admissible nocnsiuisi uo *. », -., ■ ---

Jib crane towering weight can a-jch floating in a moat ™ B ^e ° ^rd " ^et _no ^St ' ⁿ : In this case the friction to be overcome is he,

3 4

must become. Apart from the fact that this device or drives arranged in the car are formed

It should only be used to check overload protection devices. , " _C " _n ,, " _n

a special type appears suitable is also the ^c The allowable Höchstiasi ^{| to, ve} """^.";"

»Whip effect« not with this overload protection " included in the measurement. With the known

Device can therefore be the described m un..iu ". »,. , - «~ · - - ■. . Do not avoid difficulties. a change in the extension of the boom ment so A device is also known, with large, so that the diagonal pull on the ^ (each the functionality of the overload protection is weighted by the horizontal force component of a crane can be checked that the io overcoming this friction is sufficient and clasue crane in a certain cantilever position on a weight without the use of additional hinriehiunam Ground anchored weight attacks and is tracked in such a way that it is perpendicular The overload protection device does not respond to the one placed under the boom tip. . Force flow of the load rope strand switched on shear The test load can be carried out in various ways pen shears (German Auslegeschrift 1911% 2) 15 the jib crane can be applied. Preferably c To determine the crane fast, the changeable test load is already known when the.! Ud is locked, the variable tensile force in the lane to the plant is measured by means of a hydraulic cylinder. The object of the invention lies between the crane hook and the weight, and that one is switched on in the aforementioned load rope strand. Device of the type mentioned at the outset to be designed in such a way. that to raise a hefty number of jib cranes consists in the fact that the veriiidunes intermediate values the actual limit test load that can be changed with the hoist locked and Kirkeit the jib cranes under Eiiibf-pulling "the tightened load rope by actuating the \\ 1pp \ 0r-whip effect" easily and precisely determined in the direction of the crane is applied. This last , ■ can ground. ~ "25 mentioned solution should only be used for boom-to The solution to this problem is a device collar with a very sensitively working rocker arm of the type mentioned provided that the device lietein satisfactory results. Crane hook with continuously variable !, msß- With the device according to the invention is how capable of tensile force on a weight. that worked in on:

• I know that it is heavier than the permissible 30. The crane will calibrate the device is the maximum load of the jib crane. and that the L.-vst- and placed so that the vertical boom pivoting The line between the point of attack and the plane of the point of attack shows the direction of movement of the point of attack . is automatically set to "always vertical" in the weight and aligned with the weight. Then the Ausv.ird. "laid out casually in the first dimensioning to be measured In a further development of the invention, the weight 35 is ribbed and / or extended. The crane hook will movably guided on a horizontal base. hung at the point of application of the weight. so In a further embodiment of "the invention" this is the tensile force on the load bearing weight Arranged on a carriage that changes to chic and measured and the continents Values measured in parallel to the vertical "Auslegcrschwenkebcnc" are constantly measured with the is movable. "40 gchorcn-

Because of the size of the weight and because of the compared to the maximum load capacity, οι. ·, Es · ug.:. I ...

Need to achieve the approach friction of the wheels of the maximum permissible load. The rolling friction of the carriage and movement must be overcome. because of the size of the weight, it is seen that the actual extension of the outward is, the carriage does not easily follow the abscissa and the changeable a change in the projection. The horizontal load is the ordinate movement of a Y-K recorder Component of which then steer itself obliquely on the basis of the writing pad of which the crane manufac-

seen that the rope strand between booms are held in a simple manner. To this Point and point of application on the weight by means of a purpose is provided that if the match The control device is held vertically, one tensile force with that of the one that is set in each case Angle sensor overhang associated with the load limit load the Mcl.Uvrrte for the to measure a tensile force that deviates from the vertical and to register for the outreach. Inclined position of the load rope strand and one through the The tensile force can vary in size depending on one Output signal of the angle sensor ^ for resetting the predetermined limit load value can be set, dei of the load rope line can be actuated in the vertical direction to the respective off-actuator which is set under load includes. This actuator exercises on the charge heard. This has the advantage that it can be achieved. Load depending on the direction of the system deviation a 60 the crane is not overloaded by the tensile force wcrdci horizontally directed force in one way or the other, which is especially true if there is not enough fcir Direction of movement of the weight. ger application of the tensile force, z. B. by the seesaw

In doing so, the actuator can work an endless number of times, otherwise it could occur.

deflected by 180 °, by a cable winch in Ab- The measured values can be adjusted, Hiebet

depending on the output signal of the angle encoder 65 or programming of overload protection vcr

Include driftable rope, one strand of which is turned, which is attached to the cranes to be measured

Weight is on. The actuator can be arranged older. Should a jib crane measure native also of those on the moving weight, which is equipped with an overload protection with a

Power transmitter to record the load on the crane and at least one walker to record the outreach is equipped. This is how the purpose must be at least if the test load corresponds to the projection that is set in each case Limit load, the measured values for the load on the crane supplied by the force transducer are also recorded. At the same time, the measurements belonging to the load-bearing curves specified by the crane manufacturer can be measured maximum tensile forces are registered. These measured values can be used to program the switch-off curves can be used for overload protection.

Since the variable load is constantly carried on the ground, the crane can be prevented from tipping. how them by lifting the test loads in the known Procedure is given. look immediately by reducing the load.

The invention is more schematic in the following by hand Drawings on an .Example explained in more detail. Ls shows

F i g. I a perspective view of a device to determine the limit loads of jib cranes, with a mobile telescopic crane in the measuring position.

F i g. 2 is a schematic side view of the device according to FIG. I with some modifications and additions.

F i g. 3 is a diagram to illustrate the operation of the direction according to FIG. I and 2.

F i g. 4 an evaluation device for evaluating the measured values obtained with the device.

The device according to FIG. I comprises two parallel rails 1 and 2, each with two rails. on the rails 1 and 2 roll two through a bridge girder 3 to a common carriage 4 connected low loaders 5 and 6. Each low loader carries very large, the highest permissible limit loads of the jib cranes to be measured by far exceeding weights 7 in the form of two blocks.

The carriage 4 formed by the two low loaders 5 and 6 and the bridge girder 3 is by means of a Actuator 8 movable, the. as is most clearly shown in FIG. 2 shows an endless roll of two turns 9 and 10 includes deflected rope 11 in which the W'asicn 4 is switched on. Instead of Seils 11 and UmlenKrolle 9 and 10 can also a chain and sprockets may be provided.

The actuator also includes a drive motor, which drives one of the two pulleys 9 or IO and receives its control signal from a controller, which works in a manner to be described.

Between the rails 1 and 2 is a ramp 12 for the jib cranes to be measured intended. In the figures, a mobile telescopic crane 13 is in measurement position on the access ramp 12 shown. However, any other jib cranes, e.g. B. on Rail traveling jib cranes to be set up for surveying.

The telescopic crane 13 carries a luffing cylinder 15 on its rotatable upper carriage 14 pivotable telescopic boom 16. the in the F i g. 1 and 2 with the telescopes fully extended is shown. That hanging down from the Ausicgerspitze 17 Lastscil 18 is over with its flaken 19 a load cell 20. an angle sensor 21 for measuring the angle of inclination fi of the load rope strand 18 opposite the vertical, as well as a hydraulic lifting cylinder 22 posted.

The pressure in the hydraulic lifting cylinder 22 is continuously variable in a known manner and by means of a known pressure compensator indicated at 23, continuously measurable.

The controller, not shown, has the task of controlling the rope line 18 independently of the radius. always to reverberate vertically, i.e. an inclined position of the

ίο balance the load rope at an angle \\ to the vertical. The control deviation is detected by the angle sensor 21 and reported to the controller. This then gives an actuation signal to the actuator 8 in the sense of actuation of the drive motor to return the angle β to the value Nall. The drive motor is switched on until the carriage is in a position by means of the rope 11; is pulled. in which the Lastscilstrang 18 is again vertical.

If such a controller and an actuator operated by it were not available, you could see Angle | i due to pivoting of the boom from the angular position shown, in which the boom makes the angle with the horizontal <i includes. o '! he alone on the basis of a continuous Set the increase in pressure in the hydraulic lifting cylinder 22 at which the boom moves into the in F i g. 2 far exaggerated dashed position Ki 'is bent, that is, the so-called "Whipsack" learns.

Both when this PcitsehenelTect occurs as even with a change in position of the extension tip caused by a change in angle or length 17 is therefore always tracked by means of the controller of the carriage 3 in a position in which the Laslseilstrang 18 is oriented vertically.

The device further comprises a measuring cabin 24 which is arranged on the low-loader 6. This measuring cabin: is connected to the crane operator's cab 26 of the mobile telescopic crane * 13 via a line 25. In the measuring cabin 24, for example, the pressure compensator 23 is a recording device / to record the actual limit load and to compare this limit load with the one specified by the crane manufacturer Limit load. Display devices for all variables changed during the measurement and finally a control device for changing the pressure housed in the hydraulic Z \ 'Inder 22.

For the sake of clarity, the measuring cabin 24 and the crane operator's cab 26 are shown in FIG. 2 not shown.

On the one shown in FIG. 3, it will now be described how the device works.
In the diagram , the load L is plotted over the radius a, with which the jib of the jib crane is loaded. The curve g represents the limit load curve specified by the crane manufacturer, which must not be exceeded during operation. The boom 16 is symbolized by a segment of length / extending from the zero point of the diagram to the tip 17. Under load, the boom bends toward the arc 16 ', which is also drawn here with an exaggeratedly curved curve.

For the measurement, the boom is rocked

and or extension of the telescope into a position with the projection «. Then the Hook 19 on the load cell 20, the angle sensor 21 and the hydraulic cylinder 22 to the

Carriage 4 posted so that the rope IR

stands vertically.

In this position, ucr boom 16 even us erformt (s. Also FIG. 2). By increasing the pressure in the hydraulic lifting cylinder 22 in one sense, in which the piston ¹ in the / slimier retracts the boom now Id svird loaded. Because of this load it bends, ssas leads to an increase in the overhang α . In Fig. 3 thus moves at the operating point, starting from a point with the coordinates η, and L 0. in the direction of larger loads and projections on a curved curve b with increasing load in the Pleilrichtung. If the load is increased further, the operating curve b intersects the specified limit load curve g at a point with the coordinates, and L.,. The limit load L., is smaller than the limit load L _v according to the given limit load curve g without taking into account the deflection of the boom 16. That is, the so-called "whip effect" at the 20 set angle u and the set length / of the boom actually from The crane should still be able to be raised.

During the measurement evaluation, at least the coordinates of the point of intersection of curve b with curve ι? register *. One way of measuring

Curve ι; register *. Line mufnumv ,. .... FIG. 4 shows evaluation and control of the measurement shown, in which, as is known, one in the ordinate direction running rail 30 in .Y-direction and 30 a holder 31 for a pen 32 can be moved in the Y direction on this rail. As a writing pad a sheet 33 labeled or printed with the predetermined load-bearing capacity curve g is used.

By setting the correct location and scale, the YY recorder is matched to curve g. The crane driver now brings the boom into a jib at a signal from the measuring engineer. The measuring engineer then increases the pressure in the hydraulic lifting cylinder 22 from the measuring cabin 24, and curve b, recorded by the pen 32 when the pressure in the lifting cylinder 22 increases, follows on the sheet 33. When curve b intersects curve g, the measurement for radius O _{1 is} ended and the crane driver sets a new radius at which the measuring process is repeated

A measurement evaluation is also conceivable in which, apart from the extension ^ and the associated values for the boom angle and the boom length, only the coordinates of the intersection of the curves b _{5 <J} and g are recorded. This is particularly advantageous if the load on the crane hook 19 is not applied by changing the pressure in the hydraulic cylinder 22, but rather by the hoisting mechanism of the Kraus. The hoist rope is only tightened by the amount of its elongation and the amount of deflection of the jib tip. The load change takes place very quickly. An automatic measurement and registration tower at the moment when the operating rates /) intersects the Cirenz load curve i> is of particular advantage.

If the angle of inclination with respect to the horizontal changes when the boom is loaded, the procedure described above is the first to be followed. Linder by operating ties Wippzs · svirtl then the angle n svieder on (Jen original value adjusted Operation punk then lies below the courses ^ 'ssird by nochmahge-increasing the load then the final point of intersection of the operation course c b with the Grenzla-.!.; curve i> found.

The measurement described is primarily used for the Zsveck. to calibrate and / or program the overload protection of the jib crane. Such overload protection usually comprises a charging device and a power device for detecting the load, for example in the form of the Gcsar.itnioments. This is what the boom learns, as well as a computer in whose memory limit load values are preprogrammed for selected projections. By comparing the measured actual values with tie; preprogrammed limit load values, the overload safety device automatically determines the operating range in which the crane is located and switches on at over: agreement of the 1st! actual size with the given ·. Limit load size selbs.atig the crane. The limit load values obtained by the measurement described above can now be used in programming for correction of the limit load values specified by the crane manufacturer. In addition to the above-mentioned values, in particular the coordinates of the intersection of the operating curve /) with the limit load curve, the value measured by the power transmitter of the overload protection is expediently registered when this intersection is reached, so that the overload protection can be set to switch off the crane at this same measured value. 5 When carrying out the measurement, the starting point is usually and initially at the smallest radius α , i.e. the boom Ki is set as steeply as possible with the telescopes retracted. After the first measuring point has been detected, the lifting mechanism is unlocked, the extension is increased in the desired increment to the next value a, the lifting mechanism is locked again and, as described above, the boom is loaded.

1 sheet of drawings

409624/1

Λ Λ

Claims (13)

Claims; 1. Device for determining the limit loads on jib cranes, namely the jib successively brought into predetermined positions differentiated by angle and / or length is exposed to an adjustable load in each position where the load application point of the load rope the movement of the boom can be tracked, characterized in that the Crane hook (19) engages a weight (7) with continuously variable, measurable tensile force, which in a known manner is heavier than the maximum permissible load of the jib crane (13), and that the load rope strand (18) between the jib tip (17) and point of application (19) on the weight is always automatically set vertically. 2. University of Applied Sciences! according to claim 1, characterized in that dab - a device for constant comparison of the measured tensile force in the load rope with the maximum load capacity assigned to the respective outreach. 3. Device according to claim 2, characterized in that that the measured extension of the boom, the abscissa movement and the changeable Tensile force control the ordinate movement of an A'-K pen whose writing pad (33) a limit load curve 0?) Specified by the crane manufacturer is obtained. 4. Device according to one of claims 1 to 3 thereby gekennzeicnnet. oat the weight (7) a '"f of a horizontal shelf movable is led. 5. Apparatus according to claim 4, characterized in that the weight (7) is arranged on a carriage (4). of (2?) is parallel to the vertical Auslegerschwenkebenc feature <ih ^r bar on rails. 6. Device according to one of claims 1 to 5, characterized in that the load rope strand (18) between the boom tip (17) and point of application (19) on the weight (7) by means of a Control device will switch vertically, which is switched into the load rope strand (18) Angle sensor (21) for measuring an incline deviating from the vertical (angle ß) of the load step and one by the output signal of the angle encoder for resetting of the Lastscilstrangs in the vertical actuatable actuator (8) comprises. 7. Apparatus according to claim (S. characterized in that the actuator (8) is an endless, twice deflected by 180 °, by a cable winch depending on the output signal of the angle gear (21) includes antrcibbarcs rope (11), in one strand of which the weight (7) is switched on. 8. Apparatus according to claim Ci, characterized in that the actuator is formed by the drives arranged on the movable weight (7). 9. Apparatus according to claim 4, characterized in that that the weight is floating in a moat. 10. Device according to one of claims 1 to 0, characterized in that dat. Jic changeable Pulling force applied with the hoist locked by means of a hydraulic cylinder (22) is switched on between the crane hook (19) and weight (7) or in the load rope (18) is. 11. Device according to one of claims 1 up to 9, characterized in that the variable pulling force via the luffing force of the crane (13) is applied. 12. Device according to one of claims 1 to 10, characterized in that the base carrying the jib crane is relative to the displacement device of the weight (7) is rotatably arranged. 13. Device according to one of claims 1 to 12, characterized in that the tensile force between the boom (16) and the weight (7) in each selectable boom position («, /) in size to a predetermined size which belongs to the radius (a) which is established under load.