Multi-suspension-centres crane
Technical field
The present invention relates to a kind of hoisting crane, relate in particular to a kind of shipbuilding industry that is applicable to, the multi-suspension-centres crane of lifting usefulness when being specially adapted to marine drilling platform segmentation butt joint.
Background technology
Along with the proposition of domestic " marine drilling platform segmentation butt joint, integral hoisting " theory in recent years, need supporting hoisting crane and finish the lifting of this ton equipment of drilling platform, the hoisting capacity of comparing this hoisting crane with conventional hoist has increased an order of magnitude, can reach 20,000 tons even bigger, hoisting crane span and lifting altitude all reach more than 100 meter.For alleviating the weight of girder upper-part, winch is usually placed in girder and strides end.For the steel rope that guarantees multiple wraps satisfies design regulation (≤1.7 °) with the angle between reel and the pulley and avoids interfering mutually between the steel rope, the winch steel rope is restricted (as shown in figure 11) down to the span opposite side after reel one brings out rope.The major defect that the hoisting crane of this pattern exists: to the single winding of opposite side, there is locking phenomenon in the transmission that hoists to the lifting mechanism steel rope by pulley one side, and electronic force-increasing mechanism need be set; The lifting mechanism driving efficiency is low in addition, and degradation of energy is more; Specifically there is following technical matters:
1. the simply connected pattern causes single wire rope long, reaches more than 4800 meter, and cost is too high, and steel rope installation difficulty is big;
2. need arrange on girder that a large amount of dragging rollers prevents that the steel rope downwarp is excessive, complex structure;
3. the suspension centre of single group hoisting mechanism can not hoist synchronously, and electronic synchronizer gear need be set, and also needs the high harmony of electric system simultaneously;
4. the pulley multiplying power is excessive, and the driving efficiency that hoists is low, and degradation of energy is more, is easy to generate self-locking;
5. rope causes relative girders such as hoisting mechanism and leading sheave to rotate to an angle under simply connected reel and the offside span, could guarantee the requirement of deflection angle of rope like this, brings very large inconvenience to construction and installation.
Simultaneously in the pattern that adopts polyfluortetraethylene plate on stainless steel sheet, to slide usually on the hoisting crane, it between polyfluortetraethylene plate and stainless steel sheet cliding friction, friction coefficient is bigger, generally be not less than 0.15, horizontal resistance is big, and this has increased the power of driver train, generally can't use the motorized motions pattern, can only adopt hydraulic stepping to drive pattern, cause that running velocity is slow, inefficiency.For reducing the power of driver train,, the unloaded driving only is set generally in addition, if adopt fully loaded driving will make driver element excessive so that reduce to arrange size.
Summary of the invention
The present invention is directed to the proposition of above problem, a kind ofly have efficiently and develop, failure-free operating unit and shorten the installation period of hoisting crane improves the multi-suspension-centres crane that plays the life structure of lifting efficient.Technical scheme of the present invention is as follows:
A kind of multi-suspension-centres crane comprises girder, operating unit, lifting mechanism and electric-control system, it is characterized in that described operating unit comprises load carrier and driver train:
Described load carrier comprises roller devices and elastic body; Described roller devices comprises main carrying roller devices and track and horizontal bearing roller devices and track thereof, wherein, main carrying roller devices and track thereof are arranged at girder span two-side supporting under carrier bar, and horizontal bearing roller devices and track thereof only are arranged at the carrier bar both sides of girder span one side; Carrier bar is supported on girder span both sides by hinged-support; Described elastic body is arranged between described hinged-support and the carrier bar;
Described driver train adopts driven by power, comprise electrical motor, coupler, retarder, reel group, two groups of steel ropes, assembly pulley and pulley brackets, described electrical motor drives the reel group through coupler, retarder, the reel group drives steel rope, through the driving of assembly pulley realization to hoisting crane; Described reel group adopts light face reel, and steel rope adopts winding of single layer, and wherein two of first group of steel rope fag ends are individually fixed in the two ends of reel group, twine to the middle part along the end of reel group, and in a side rope stretching of reel group; Two fag ends of second group of steel rope then are individually fixed in the middle part of reel group, twine to the end along the middle part of reel group, and its winding direction is opposite with the winding direction of described first group of steel rope, and in the opposite side rope stretching of reel group; The angle of two groups of steel ropes and reel group vertical plane all is not more than 1.7 °;
Described lifting mechanism comprises the above hoisting mechanism of the cover of 2 on the every girder, for every cover hoisting mechanism, comprise that the centre adds the double crosslinking drum group of division board, two steel ropes and two last leading sheaves, and correspondence comprises that being positioned at the girder homonymy with described double crosslinking drum group strides the individual fixed pulley group of two following leading sheaves, (2n+1) of end and suspension hook group and 2n suspension hook attaching parts identical with fixed pulley group quantity, wherein, the integer of n=1~4;
Described two steel ropes are wrapped in the division board both sides of described double crosslinking drum group separately, and respectively through its separately last leading sheave, between described fixed pulley group and suspension hook group, adopt symmetrical winding form behind the leading sheave down, promptly in described every cover hoisting mechanism, two steel ropes are twined to middle symmetry by the fixed pulley group and the suspension hook group on both sides respectively, and its terminal is individually fixed on the equilibrium arm; Described 2n suspension hook attaching parts forms hinged by bearing pin with cooresponding suspension hook group respectively or captives joint pattern; Described hoisting mechanism is section between leading sheave on double crosslinking drum group that the girder homonymy is striden end is cooresponding to it, is arranged in respectively on the different vertical dimensions.
Respectively arranged 2-4 row under each carrier bar of girder span both sides in the described operating unit, every row 2-20 row main carrying roller devices and track thereof; 1-2 row has respectively been arranged in each carrier bar both sides of described girder span one side, every row 2-20 row horizontal bearing device and track thereof.
The individual suspension hook group of (2n+1) of every cover hoisting mechanism and cooresponding 2n suspension hook attaching parts thereof are linked to be a single-piece movable pulley equalizing bar in the described lifting mechanism.
Two steel ropes in the described lifting mechanism adopt the multiple wraps pattern to be wrapped in the division board both sides of described double crosslinking drum group separately.
Described girder can be single girder or many girders.
Described electric-control system comprises the control system of being made up of frequency converter, communication module and electrical motor that hoists, the operation control system of being made up of frequency converter, communication module and electrical motor, and controller, load transducer, position transduser and upper computer;
Described controller is responsible for receiving control command, return state information with upper computer communication, controls the operation of each lifting mechanism and operating unit, the feedback signal of receiving sensor simultaneously;
Described load transducer and position transduser with the tractive force of the load capacity of each lifting mechanism and sling height, operating unit and travel position by self with communication module pass to controller, by adjusting the operation of each lifting mechanism and operating unit after the processing of controller;
Its middle controller, sensor, the control system that hoists, the control system that hoists all connect by bus mode.
A kind of control method of operating unit, it is characterized in that carrying out when mobile when hoisting crane, is the better synchronized operation of the operating unit at control girder two ends, usually wherein the operating unit of an end as reference side mechanism, the other end is as following side mechanism, and concrete control process comprises the steps:
A, reference side mechanism controls process are as follows:
1) after traversing operation is ready to, mentions anchoring device, open drg;
2) detect all earth anchors and lift and put in place, all drgs be opened to open a sluice gate spacing after, traversing motor brings into operation, motor adopts closed loop control, when the deviation of actual speed and given speed during greater than setting value, compensates automatically;
3) in traversing process, detect the size of actual tractive force simultaneously, if actual tractive force is greater than 110% of rated drawbar pull, system's emergency engine kill, the fault cause of brake, and investigation simultaneously;
4) after traversing putting in place, and after detecting all motor speeds and being zero, all drgs are braked simultaneously, traversing EO;
B, to follow side mechanism controls process as follows:
1) after traversing operation is ready to, mentions anchoring device, open drg;
2) detect all anchoring devices and lift and put in place, all drgs be opened to open a sluice gate spacing after, traversing motor brings into operation, motor adopts closed loop control, when the deviation of actual speed and given speed during, compensate automatically greater than setting value,
3) in traversing process, do the size detection with the deviation of stroke and the actual tractive force of reference side, carry out following steps according to testing result then:
A, if with the deviation of stroke of reference side greater than setting value, can judge that then to follow side speed fast, control system will be followed side frequency converter velocity setting and be reduced in proportion; Otherwise if with the skidding journey less than the reference side stroke, can judge that then to follow side speed slow partially, will follow side frequency converter velocity setting and scale up and follow the side velocity compensation;
B, if with the tractive force deviation of reference side during greater than setting value Δ 1, control system will be followed the tractive force of side according to this bias adjustment, compensate adjustment;
C, if with the tractive force deviation of reference side during greater than Δ 2, system's emergency engine kill, brake prevents grave accident simultaneously;
D, if actual tractive force greater than 110% of rated drawbar pull, brake simultaneously, and investigation fault cause;
4) after traversing the putting in place, and after detecting all motor speeds and being zero, all drgs are braked simultaneously, traversing EO.
Compared with prior art, the present invention has following significant advantage:
Wherein the operating unit roller is made the operation rolling member, and load-carrying capacity is big, speed is big, and electric driving device is simple in structure, and is easy to maintenance; Be arranged at the elastic body between hinged-support and the carrier bar,, offset installation error effectively as the special construction of symmetrical load, guarantee that each roller is on the plane and stressed evenly.Adopt the Vidacare corp of reel group heteropleural four rope stretching forms, simple in structure for operating mechanism of multi-suspension-centres crane provides a kind of rational solution, easy to maintenance; Simultaneously, heteropleural four goes out rope structure also to be played the fixing effect of hoisting crane, as long as drg is in the lock state that closes, then hoisting crane can be along the track slippage with regard to being fixed.In addition, horizontal bearing roller devices and track thereof only are arranged at a side of crane girder span, and opposite side does not then have the level constraint, have guaranteed the statically determimate structure of main beam stress; The every side master of span was carried evenly bearing load of roller devices when hinged-support had guaranteed the distortion of girder vertical direction.
Wherein lifting mechanism adopts double crosslinking drum, steel rope multiple wraps and symmetry rope pattern down, novel structure, solved that superduty large span crane rope drift angle is not easy to guarantee and the steel rope level twines that distance is long, mechanism efficiency is low excessively, mechanism is easy to generate a series of problems such as self-locking, suspension centre is asynchronous, difficulty of construction is big, also had simultaneously:
(1) reduced the coiling length of single wire rope greatly, cost reduces, and the steel rope installation period shortens;
(2) net synchronization capability between the suspension hook group of every cover hoisting mechanism improves greatly;
(3) the pulley multiplying power reduces, and the driving efficiency of winding system obviously improves, and avoids mechanism's self-locking;
(4) difficulty of construction and operating cost reduce greatly.
In a word, the present invention has safe and reliable, and practical characteristics can be avoided great potential safety hazard, is applicable on the ton super large hoisting capacity hoisting crane, the multi-suspension-centres crane of lifting usefulness when being particularly useful for marine drilling platform segmentation butt joint.
Description of drawings
Fig. 1 is the structural representation of hoisting crane of the present invention;
Fig. 2 is the structural representation of the embodiment of operating unit among the present invention;
Fig. 3 is a M partial enlarged drawing among Fig. 2, the enlarged drawing of promptly main carrying roller devices;
Fig. 4 is the birds-eye view of Fig. 2;
Fig. 5 is the left view of Fig. 2;
Fig. 6 has installation error to cause the not scheme drawing at grade time of its lower plane under two carrier bars;
Fig. 7 is the scheme drawing that elastic body is offset above-mentioned installation error;
Fig. 8 is the heteropleural four rope stretching structural shape scheme drawings of reel group;
Fig. 9 is the reference side mechanism program flow diagram of operating unit of the present invention;
Figure 10 be operating unit of the present invention follow side mechanism program flow diagram;
Figure 11 is the typical structure scheme drawing of restricting under the steel rope offside span in the prior art;
Figure 12 is the structural representation of embodiments of the invention;
Figure 13 is the birds-eye view of Figure 12;
Figure 14 is the enlarged drawing of the cover hoisting mechanism of one among Figure 12 (IV);
Figure 15 is that example shows that steel rope duplex, multilayer, symmetrical expression twine the scheme drawing of pattern with hoisting mechanism (IV);
Figure 16 is the C-C section-drawing among Figure 14;
Figure 17 is suspension hook attaching parts scheme drawing I;
Figure 18 is suspension hook attaching parts scheme drawing II;
Figure 19 is the structural representation of the two ends suspension hook group of every cover hoisting mechanism;
Figure 20 is the structural representation of the middle suspension hook group of every cover hoisting mechanism;
Figure 21 is a double crosslinking drum group structural representation;
Figure 22 is the structural representation that the suspension hook attaching parts adopts the lifting mechanism of another kind of modification structures;
Figure 23 is the enlarged drawing of the cover hoisting mechanism of one among Figure 22 (IV);
Figure 24 is the annexation enlarged drawing of suspension hook attaching parts and suspension hook group;
Figure 25 is the control system functional block diagram.
The specific embodiment
As shown in Figure 1, a kind of multi-suspension-centres crane comprises girder 3, operating unit 1, lifting mechanism 2 and electric-control system 4, and wherein electric-control system comprises the control system of being made up of frequency converter, communication module, electrical motor 401 that hoists, operation control system 402, controller 403, load transducer 404, position transduser 405, the upper computer 406 be made up of frequency converter, communication module, electrical motor equally;
Described controller is responsible for receiving control command, return state information with upper computer communication, controls the operation of each lifting mechanism and operating unit, the feedback signal of receiving sensor simultaneously;
Described load transducer and position transduser with the tractive force of the load capacity of each lifting mechanism and sling height, operating unit and travel position by self with communication module pass to controller, by adjusting the operation of each lifting mechanism and operating unit after the processing of controller;
Its middle controller, sensor, the control system that hoists, the control system that hoists all connect by bus mode.
The present invention is directed to existing multi-suspension-centres crane and mainly on operating unit 1 and lifting mechanism 2, done significantly improvement, specific as follows:
Described operating mechanism of multi-suspension-centres crane 1 as Fig. 2, Fig. 4 and shown in Figure 5, comprises load carrier and driver train.
Described load carrier comprises hinged-support 101, main carrying roller devices 102, main bearing track 103, horizontal bearing roller devices 104, horizontal bearing roller track 105, carrier bar 106, elastic body 121 etc.; Described main carrying roller devices 102 and track 103 thereof as shown in Figure 3, are arranged at crane girder 3 span two-side supportings in carrier bar 106 times, have respectively arranged 2 rows, 8 row under each carrier bar, as shown in Figure 2; And 105 on horizontal bearing roller devices 104 and track thereof are arranged at carrier bar 106 both sides of girder 3 spans one side, and every side has been arranged 1 row, 6 row, as shown in Figure 5; All by heavy roller finished product buying, pattern is seen the M enlarged drawing among Fig. 3 for main carrying roller devices 102, horizontal bearing roller devices 104.Above-mentioned one-sided no level retrains the design of promptly not having level carrying roller devices and track thereof, has guaranteed the statically determimate structure of main beam stress; Carrier bar 106 is supported on girder 3 span both sides by hinged-support 101, and two groups of masters of the every side of span are carried evenly bearing load of roller devices 102 when having guaranteed the distortion of girder 3 vertical direction; Described elastic body 121 is arranged between described hinged-support 101 and the carrier bar 106, when two carrier bars 106 of hoisting crane one end cause its lower plane not on same plane because of installation error, as shown in Figure 5, two sections elastic bodys 121 have produced different deflections under the different pressures effect, above-mentioned installation error is offset, thereby guaranteed that each roller acts on the plane and stressed evenly, as shown in Figure 6.
Anchoring device 122 is fixed on the carrier bar 106, and the voussoir when shutting down work in the anchoring device 122 is inserted in the hoisting crane support rail beam 107, plays the windbreak anchoring effect.
Described driver train adopts driven by power, drive reel group 112 with electrical motor 108 through coupler 109, retarder 111, reel group 112 drives the driving that steel rope 113, steel rope 114 difference pile warp assembly pulleys 115, assembly pulley 116 and assembly pulley 117, assembly pulley 118 are realized hoisting crane; Pulley bracket 119 is installed on the basis.The reel group adopts heteropleural four rope stretching patterns, as shown in Figure 8, i.e. steel rope winding of single layer, wherein two of steel rope 113 fag ends are fixed in the two ends of reel group 112 respectively by steel rope pressing plate 123, twine to the middle part end along reel group 112, and in a side rope stretching of reel group 112; Two fag ends of steel rope 114 then are fixed in the middle part of reel group 112 respectively by steel rope pressing plate 123, twine to the end along the middle part of reel group 112, and its winding direction is opposite with the winding direction of described steel rope 113, and in the opposite side rope stretching of reel group 112; The angle of two groups of steel ropes and reel group 112 vertical planes all is not more than 1.7 °, disorder cable not when guaranteeing that two groups of steel ropes twine; When reel group 112 was rotated, as steel rope 113 slack ropes, then steel rope 114 tight ropes realized that hoisting crane moves to the left; In like manner as steel rope 113 tight ropes, then steel rope 114 slack ropes have realized that hoisting crane moves to the right.This mechanism also plays the fixing effect of hoisting crane simultaneously, as long as drg 110 is in the lock state that closes, then hoisting crane can be along the track slippage with regard to being fixed.It is big that described operating unit 1 bears wheel load, running resistance is little, running velocity is big, and it is maintainable good, can effectively improve the work efficiency of hoisting crane, plan is used it on the ton superduty multi-suspension-centres crane, can avoid great potential safety hazard, estimates that every hoisting crane can save handling cost 1,000,000 Renminbi every year.
When hoisting crane carries out when mobile, be the better synchronized operation of the operating unit at control girder two ends, wherein the operating unit of an end is as reference side mechanism usually, and the other end is as following side mechanism, and concrete control process comprises the steps:
Reference side mechanism controls process is as follows as shown in Figure 9:
1) after traversing operation is ready to, mentions anchoring device, open drg;
2) detect all earth anchors and lift and put in place, all drgs be opened to open a sluice gate spacing after, traversing motor brings into operation, motor adopts closed loop control, when the deviation of actual speed and given speed during greater than setting value, compensates automatically;
3) in traversing process, detect the size of actual tractive force simultaneously, if actual tractive force is greater than 110% of rated drawbar pull, system's emergency engine kill, the fault cause of brake, and investigation simultaneously;
4) after traversing putting in place, and after detecting all motor speeds and being zero, all drgs are braked simultaneously, traversing EO;
It is as follows to follow side mechanism controls process as shown in figure 10:
B, to follow side mechanism controls process as follows:
1) after traversing operation is ready to, mentions anchoring device, open drg;
2) detect all anchoring devices and lift and put in place, all drgs be opened to open a sluice gate spacing after, traversing motor brings into operation, motor adopts closed loop control, when the deviation of actual speed and given speed during, compensate automatically greater than setting value,
3) in traversing process, do with the deviation of stroke of reference side and (utilize and be provided with laser ranging system in the both sides of girder, detect in real time the stroke of both sides) and the size detection of actual tractive force (sheave shaft in the assembly pulley is a load transducer, can detect tractive force in real time), carry out following steps according to testing result then:
A, if with the deviation of stroke of reference side greater than setting value, can judge that then to follow side speed fast, control system will be followed side frequency converter velocity setting and be reduced in proportion; Otherwise if with the skidding journey less than the reference side stroke, can judge that then to follow side speed slow partially, will follow side frequency converter velocity setting and scale up and follow the side velocity compensation;
B, if with the tractive force deviation of reference side during greater than setting value Δ 1, that is: when both sides tractive force deviation during greater than setting value Δ 1, promptly the both sides tractive force is unbalanced, illustrate that girder one side exists to move the jam phenomenon.Can work in coordination with the stroke detection result this moment and carry out the jam investigation, adjust the both sides tractive force and adjust with reference to the direction of main beam stress this moment, for example: illustrate greatly then that when girder becomes at the suffered resistance of reference side the reference side operation is subjected to jam, can reduce to follow the tractive force (or tractive force of increase reference side) of side on the one hand, can on-the-spotly investigate jam on the one hand, reach the girder two ends and advance synchronously, make the girder smooth running.
C, if with the tractive force deviation of reference side during greater than Δ 2, that is: when both sides tractive force deviation during greater than setting value Δ 2, promptly the both sides tractive force is extremely unbalanced, and the very big operation jam phenomenon of girder one side existence be described.If untimely ascertaining the reason may cause the girder steel structure impaired, can cause girder to tumble when serious, grave accident takes place, system's emergency engine kill, brake prevents grave accident simultaneously;
D, if actual tractive force greater than 110% of rated drawbar pull, brake simultaneously, and investigation fault cause;
4) after traversing the putting in place, and after detecting all motor speeds and being zero, all drgs are braked simultaneously, traversing EO.
Described hoisting mechanism of multi-lifting-point joint crane 2 as shown in Figure 12 and Figure 13, is arranged 6 cover hoisting mechanisms on the every girder, respectively with Roman number I, and II, III, IV, V, VI represents;
Every cover hoisting mechanism as shown in figure 14, adds the double crosslinking drum group 214 of division board 220 in the middle of including, as shown in figure 21, also comprise two steel ropes 210,211, be positioned at girder 3 homonymies with described double crosslinking drum group and stride two of end and go up leading sheaves 212,213, two following leading sheaves 207,209, three fixed pulley groups 204,205,206 and three cooresponding suspension hook groups 201,202,203, respectively as Figure 19, shown in Figure 20, and 2 suspension hook attaching partss 215,216, respectively as Figure 17 and shown in Figure 180;
Described two steel ropes 210,211 separately multiple wraps on division board 220 both sides of described double crosslinking drum group 214, and respectively through its last leading sheave 212 separately, 213, following leading sheave 207,209 backs are in described fixed pulley group 204,205,206 and suspension hook group 201,202, adopt symmetrical winding form between 203, i.e. two steel ropes 210,211 are twined to the fixed pulley group 205 and suspension hook group 202 symmetries of centre by the fixed pulley group 204,206 and the suspension hook group 201,203 on both sides respectively, and its terminal is individually fixed on the equilibrium arm 208, as shown in figure 15;
Described 2 suspension hook attaching partss 215,216, as Figure 17 and shown in Figure 180, it is respectively by stub axle 218 and cooresponding suspension hook group 201,202,203 is hinged, or respectively simultaneously by stub axle 218 and ear's bearing pin 219 and cooresponding suspension hook group 201,202,203 captive joints, as shown in figure 24; Its concrete pattern that connects adopts grafting, as shown in figure 16.
Described hoisting mechanism girder 3 homonymies stride the double crosslinking drum group of end cooresponding to it on section between the leading sheave, be arranged in respectively on the different vertical dimensions.
For big elevating height, organize the big multiplying power lifting mechanism 2 of suspension hook group more, its hoisting mechanism adopts above-mentioned duplex multiple wraps reel, double-steel wire rope to stride the layout pattern of restricting under the end at the homonymy of girder 3, avoided in the simply connected pattern steel rope one to bring out after the rope span offside rope down, as shown in figure 11, reel group and the excessive problem of last leading sheave spacing; Under the condition that guarantees deflection angle of rope, double crosslinking drum pattern and simply connected reel pattern relatively greatly reduce the multiplying power of assembly pulley, the lifting mechanism driving efficiency has improved 20%, and the length of single wire rope is reduced to 2200m by 4800m, shortens the steel rope installation period in the time of cost-cutting greatly.Double crosslinking drum and go up leading sheave and keep the layout of a determining deviation to make the easier assurance of deflection angle of rope, hoisting mechanism and leading sheave group etc. need not the installation that rotates to an angle of relative girder 3, greatly reduce difficulty of construction.
On the other hand, steel rope twines pattern by the both sides assembly pulley to the symmetry of intermediate pulley group, guaranteed hoisting synchronously between a plurality of suspension hook groups of single cover hoisting mechanism: during the independent lifting operation of a cover hoisting mechanism, after suspension hook attaching parts 215,216 couples together by bearing pin, under the winding pattern of symmetrical lay winding wire ropes, lift by crane, suspension hook group 201,202,203 can hoist synchronously, avoid adopting other measure as electronic synchronizer gear etc. is set, simplify mechanism, improved the reliability of complete machine work.
And special many suspension hooks group connecting device has solved nonsynchronous problem of many suspension centres hyperstatic structure and each suspension centre:
When zero load is lifted by crane, for the suspension hook group that guarantees every group of hoisting mechanism synchronously, all suspension hook groups by ear's bearing pin 219 and 218 combineds action of stub axle, are connected into rigid body with suspension hook attaching parts 215,216;
And when fully loaded lifting or the suspension centre of the weight of every group of hoisting mechanism lifting not on same horizontal linear the time, discharge the ear's bearing pin 219 between suspension hook group and the suspension hook attaching parts 215,216, and only realize hinged between suspension hook groups and the suspension hook attaching parts, thereby the degree of freedom of assurance suspension hook group vertical direction by stub axle 218.
As a kind of modification of such scheme, described 3 suspension hook groups 201,202,203 and cooresponding 2 suspension hook attaching partss 215,216 thereof form and are linked to be a single-piece movable pulley equalizing bar 217, as Figure 22 and shown in Figure 23.
This lifting mechanism also has a maximum characteristic to be exactly in addition, its automatically controlled part can adopt mode in the past to control, have good commonality, for example adopting patent name is that " multiple hanging points crane electric control method " patent No. is that the control method of saying description among the 200710011935X is controlled.
The above; only be the preferable specific embodiment of the present invention; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses; be equal to replacement or change according to technical scheme of the present invention and inventive concept thereof, all should be encompassed within protection scope of the present invention.