EP3878794A1

EP3878794A1 - Service crane

Info

Publication number: EP3878794A1
Application number: EP20460015.9A
Authority: EP
Inventors: Tomasz Paszkiewicz; Marek Metelski; Kamil Nadratowski
Original assignee: Protea
Current assignee: Protea
Priority date: 2020-03-13
Filing date: 2020-03-13
Publication date: 2021-09-15

Abstract

Service crane (1) permanently attached by the base (2) to the ground (3), and also being equipped with a control system (4) and an extension arm (5); through the motor (6) horizontally rotational, and a mobile bearing plate (7) connected to the base (2) rotationally and slidingly. The extension arm (5) at one of its ends is attached to the bearing element (8) mounted on the bearing plate (7), which together constitute the main elements (9) of the solebar (10), while at its other end the arm (5) is equipped with a head (11) with a reel (12) on which is supported the working rope (13) running through the extension arm (5) to the winding drum (22) one way and to the hook (14) the other way. The extension arm (5), possibly having a blockade of the vertical movement, connects with the solebar (10) at least indirectly at least at two support points, preferably with a pin embedded in an articulated eye joint. The articulated joint (18) in an amount of at least one is located in the upper zone (19) of the soiebar (10). The complementary element (21) of the solebar (10) is a light bar structure (21 ') made in the form of two placed oppositely to each other steel stays (21a, 21b), preferably in the form of steel plates, which are fixed preferably detachably to the a bearing element (8) of the solebar (10) and to the bearing plate (7) of the solebar (10). Between the steel stays (21a, 21b) is mounted detachably the winding drum (22) inside of which there is a slip clutch (25), preferably with a gearbox (24), which slip clutch (25) connects the winding drum (22) with its driving motor (26). The driving motor (26) is located just behind one of the steel stays (21a), while the motor (6) of the horizontal rotation is located between the bearing pillars (27) constituting the rear bearing element (8) of the solebar (10). At the same time, the extension arm (5) having a framing construction, on the edge of each rod (5 ') of its framing construction, has an eye element (28) of the articulated joint (16,18), where the eye element (28) with their outline form the base (29), of the extension arm (5) which base (29) of the extension arm (5) for the extremely lowered position of the extension arm (5) is laid at an acute angle to the horizontal having the second two support points connecting the extension arm (5) with the solebar (10), each in the form of a pin (15a, 15b) embedded in an articulated eye joint (16) located in the front lower zone (20) of the solebar (10) at its edge.

Description

The subject of the invention is a service crane used in particular in hard-to-reach places, e.g. where space for the foundation or mobility of the crane elements is limited, and at the same time the necessity to use such a device is beyond doubt. As a rule, they are most often used as cranes on offshore platforms, on wind farms, as technical cranes for moving elements, including small containers from a service ship to a wind power plant service platform, which is usually located at a significant height in the middle or upper parts of a wind power plant column. These types of cranes can also be used in other offshore installations as devices with a low load capacity, generally not exceeding ten tonnes.
As a rule, the service cranes for the indicated use should be characterized by simplicity of execution, ease of servicing and adaptation to occasional use. In addition, all their components must be properly protected for operation of difficult sea weather conditions, i.e. also taking into account significant salinity. All of this in order to minimize service operations with simultaneous maximization of reliability. Scheduled service work, and even more so repairs at sea due to breakdowns are very expensive and difficult. Due to the two-way transhipment in an open sea, the service cranes are classified as offshore type and it is necessary that they meet the requirements associated with this class of cranes, including due to the protection resulting from high dynamic loads and hazards arising when picking up a cargo from the delivery vessel. The threats should counteracted by the security systems that are designed anticipating the inconveniences of the functioning of equipment in such difficult conditions. Most often occurring are associated with the phenomenon of overloading of suspension cables and drives, called under the abbreviations AOPS and MOPS ('Automatic Overload Protection' and 'Manual Overload Protection'). Cranes of this type must be characterized by low energy consumption because the energy to power equipment on farms must be supplied from land, which is expensive. Ensuring low energy consumption can be accomplished by miniaturization and unweight, which will allow the use of lower power for drive motor, however, it should be remembered that it is also necessary to ensure high strength, maximum load capacity and range of the device arm. This seems to be a contradictory assumption, however, constructions are created taking into account, at least partially, most of the above-mentioned issues.
For the indicated purpose, two types of crane construction are used: crane and davit. Another name indicates a certain structural difference, which is the function of vertical movement of the arm. The davit does not have it. Both types, however, have the same function associated with the rotation of the arm around its base, which is permanently attached to the ground on which the device is placed.
The known constructions have been put together to improve at least one of the already discussed parameters.
From the European patent number EP2665674B1 is known a crane designed for servicing offshore wind farms. The known crane is permanently attached with its base to the service platform and has ensured a rotational mobility of the bearing plate mounted on this base. It is equipped with a solid arm, folded downwards at its top, which at one end is pivotally attached to the solebar mounted on the bearing plate, and at its other end it is equipped with a head with a reel on which is based the crane working rope. The arm pivotally attached to the solebar is vertically moved on the upper front pin due to the fact that to the lower front pin is attached the actuator piston, and the end of the internal actuator core, having a transverse pin, is attached with a pin in the eye located from the front side of the part of the crane arm running up. The piston being positioned entirely between two attachment points ensures arm vertical movement, while the arm also has the option of the blockade of the function of vertical movement. The blockade is performed by means of an extensible upper rear pin, which, at the moment of crossing the solebar and the arm, immobilizes this crane arm creating with the second a lower support point for the arm. At the moment of locking the actuator is fully extended, however, the arm position still remains the position with an angular tilt of the arm forward with respect to the vertical. In the absence of a retractable pin, the position of the arm may be vertically moved, but its extreme lower position after maximum forward inclination is also not a position giving a horizontal arm position. Although the arm is more inclined from the vertical, it is still inclined at an acute angle to the horizontal service platform, i.e. it is not parallel to the platform. Alternatively, the folded front part of the arm having the head runs horizontally relative to the platform, but only when the actuator is fully extended and the arm is maximally raised. The presented known solution still needs a significant amount of space necessary to operate the device and needs a lot of it even when the crane is in a rest position with the arm blocked by the upper rear pin. The operating range of this known crane is severely limited, having in mind its considerable complexity. Also significant is its weight because it is made of full steel profiles. It seems that the only advantage can be its control mechanism in the field of winding and unwinding the working rope.
From another known solution, this time the British invention number GB2482370B , is known a davit that can be used on wind farms or ships to lift cargo from an independent watercraft deck. The crane is equipped with a rope mechanism that releases or reels the rope, but there is also a system that stabilizes the rope release depending on the movement of the rope, including fluctuations and stresses. Stabilization consists in a compensation of abnormal rope movements and diverging from the expected release / reeling of the rope in a unit of time. The compensation is made thanks to a spring element, which is a component of the rope mechanism. Unfortunately, the spring element cannot be sufficiently precisely controlled, which makes a very big difference, because this particular field of technology is tightened up by a number of boundary conditions that should be observed each time the load is lifted or lowered.
As a rule, from the safety standards there result certain specific overload values that are acceptable when operating a crane. After exceeding of these values are , should turn on, preferably in an automatic way, the safety systems which enforce a specific mode of operation, i.e. either they brake the rope by a specific value, or change its mode of operation, or stop it with a brake. It is evident that it is not always possible sudden stop, so-called 'in place'. As a result of this forced stopping is still working the inertia of the load suspended on the rope, which may lead to the load breaking off the rope, breaking the rope, damage to the crane, and finally to damages broadly understood, i.e. concerning also the people and objects being in the immediate vicinity of operating devices and mechanisms.
An example of a known solution that just corrects this bi-directional movement of the rope is described in the application of the invention with the number AU2016342566A1 , in which has been discussed the construction of the dedicated for manual safe operation of the rope running through the reel constituting the drive wheel. The movement of the drive wheel is limited by a centrifugal brake and gearbox, which, through toothed gears, affect, in consequence, the movement of the rope embedded and running through the interior of the device. The device, however, could not be suitable for lifting heavy loads, and even more so it will not meet the high requirements for offshore cranes and davits.
From another British application with the number GB2160170A1 , is known a crane, which has a folding horizontal arm that has additionally its own boom consistent with the direction of its own horizontal arm, whereby the horizontal arm is supported on a pillar made of a solid one-sided open profile, and is also supported by a pin on the actuator attached also at the foot of the pillar in the inner contour of the one-sided open profile.
In addition, there is attached, working as a winch, drive for slight additional lifting upward of the horizontal arm, which results in the possibility of setting the obtuse angle between the pillar and the horizontal arm. After folding, the horizontal arm takes a vertical position and lays out along the post. The crane is still a heavy crane, as a rule, it has a slowly following the actuator movement horizontal arm movement, which additionally may extend pulling-out, which unfortunately takes an extra time period.
From the European patent number EP 3020622B1 is known an offshore davit, which is made of two functional parts, namely the first one is a pillar attached to the service platform at the destination place, to which pillar the boom arm is permanently attached, and the second part is lifting assembly, which one is the only that has mechanisms, including a hook, rope, motor and winding drum for the rope, which as a set are pulled under the arm of the boom and there detachably fixed to it. Only the two parts connected together obtain the functions that are to be expected in previously known non-folding davits. The construction seems to unnecessarily cause problems consisting of in fitting both parts, the more so that the other functions of the davit are not improved.
Bearing in mind all the imperfections of cranes and service davits, which on the known examples were described in the content above, the intention for the innovative construction of the present invention was an assembly of the construction which will ensure both the best functional operation of the reach for cranes by allowing a vertical movement in a range basically from the horizontal position of the arm boom to the basically vertical position of the arm boom, without damage for the strength and carrying capacity of the construction, despite the independently increased reach, and at the same time with less restrictions on the movements of the crane, as well as leaving mobility only in horizontal will also assure a reduction of the limitation of movements of the davit which, with its construction, with only exception of a modest amount of elements of the vertical movement, is identical to the construction of a crane, which means that the construction can be converted. The overriding goal, however, for a compact and lightweight at the same time, which seems unobvious, structure according to the invention, in addition to the previously indicated minimization of the area for the foundation of the service crane, while simultaneous ensuring its greater operability, it is primarily providing a quick possibility of repair in case of a breakdown, e.g. by replacing a specific component of the crane and ensuring increased safety despite this compactness, associated with raising and lowering of the load on the carrying rope released from the compact construction of the service crane, crane or davit, intended for handling loads lifted from the balancing deck of the ship, often also in gusts of wind.
Conversion of the crane into a davit and vice versa, although it is a side goal of the invention, despite the difficult conditions in the environment of the offshore cranes, is in principle just as possible as quick repairs of the crane by replacing components, despite the special place of foundation of the construction, and both constructions are, as a rule, safe and also meet detailed above-average technical requirements related to cranes of the offshore type.
The service crane according to the invention is permanently attached by the base to the ground and also, being equipped with a control system and an extension arm has ensured thanks to the horizontal rotation motor the mobility of the bearing plate connected to the base rotationally and slidingly. The extension arm at one end is attached to the weight-bearing element mounted on the bearing plate, constituting together the main elements of the solebar, while at its other end the arm is equipped with a head with a reel on which is supported a working rope running through the extension arm up to the winding drum one way and up to the hook another way. The extension arm, possibly having a blockade of the vertical movement connects with the solebar at least indirectly at least at two support points, preferably with a pin embedded in the articulated eye joint. The articulated joint in an amount of at least one is in the upper zone of the solebar. The invention is characterized in that the complementary element of the solebar is a light bar structure made in the form of two placed oppositely to each other steel stays, preferably in the form of steel plates, which are fixed preferably detachably to the bearing element of the solebar and to the bearing plate of the solebar. Between the steel stays is fixed detachably the winding drum inside of which there is a slip clutch, preferably with a gearbox, which slip clutch with the gearbox connects the winding drum with its drive motor. The drive motor is located just behind one of the steel stays, while the horizontal rotation motor is located between the bearing pillars constituting the rear bearing element of the solebar. At the same time, the extension arm having a framing construction, on the edge of each rod of its framing construction, has an eye element of the articulated joint, where the eye elements with their outline form the base of the extension arm, which base of the extension arm for the extremely lowered position of the extension arm is at an acute angle to the horizontal having the second two support points connecting the extension arm with the solebar, each time in the form of a pin mounted in an articulated eye joint located in the front lower area of the solebar at its edge.
Preferably, the horizontal rotation motor is connected to the bearing plate via a gearbox from which the first gear wheel is permanently attached to the base and is being at its extreme upper side, and the second gear wheel is axially connected to the horizontal rotation motor embedded in the solebar, the second gear wheel is located from the underside of the bearing plate of the solebar.
Preferably, the bearing plate of the solebar is connected to the base slidingly by bearing system.
Preferably, the drive motor of the winding drum is located on the extension of the axis of the winding drum.
Preferably, the horizontal rotation motor is detachably attached to the solebar and is located on the edge of the solebar bearing plate in the rear area of the solebar.
Preferably, the bearing element of the solebar are pillars made of rolled profiles..
Preferably, the extension arm has reinforcements located at least in the immediate vicinity of the eye elements of the articulated joint at the edge of each rod of the framing construction
Preferably, the extension arm has a blockade of the vertical movement and connects to the solebar directly at four support points, each time with a pin permanently fixed in the articulated eye joint, where the articulated joints in the amount of two are in the upper area of the solebar at the top of the bearing element, and the other articulated joints in the amount of additional two are located in the front lower zone of the solebar on its edge
Alternatively preferably the extension arm has the function of vertical movement and connects with the solebar directly in two support points each time with a pin permanently mounted in the articulated eye joint in the upper zone of the solebar at the top of the bearing element, and also connects to the solebar indirectly through the actuator and two support points, each time with a pin permanently fixed in the articulated eye joint the other two pins are an extension of the clamping ring catching the cylinder that end of the piston rod is attached with an additional pin in an additional articulated joint located in the front lower zone of the solebar on its edge. The cylinder of the actuator is then retracted inside of the framing construction of the extension arm, where the extension arm is attached to the bearing element pivotally. Preferably then, from the position of the actuator with the piston rod fully extended, the position of the extension arm is close to vertical, and in the position of the actuator with the piston rod fully retracted, the position of the extension arm is close to horizontal. Preferably, then the actuator has an electro-hydraulic drive, and the electric motor of the electro-hydraulic drive is attached to the cylinder of the actuator and is retracted together with the actuator inwards the lattice construction, while the clamping ring catching the cylinder of the actuator is located at the root of the cylinder, i.e. on the opposite side of the bottom of the cylinder.
Preferably, the release and winding of the working rope is controlled by a signal of the current overload of the working rope, the control system is coupled through the remote sensor of the overload of the working rope with a slip clutch of the winding drum and / or a gear of the winding drum.
Preferably, the crane is controlled from a portable cassette.
Preferably, the head with the reel mounted on the top of the extension arm is a maintenance free head, with the sensor of the overload of the working rope is located at a considerable distance from the head and preferably equipped with a radio connection is located at the contact of the working rope and the swivel, or the hook of the working rope, as a removable equipment.
Preferably, the ground is the service platform of the serviced device.
The solution, as a rule, in the version with a vertically moved arm i.e. as a crane, allows to reduce the dimensions of the storage platform of the serviced machine. The advantage is that the lattice boom of the crane has the same appearance / shape as the one used for the version without the vertical movement, i.e. for the davit. The advantage is also that the use of an electro-hydraulic actuator is economical and at the same time very durable and reliable, because it does not give the possibility of oil leaks that occur with traditional hydraulic drives.
The advantage is also that in the crane version, the special arrangement and mounting of the actuator allows for approximately twice as fast operation of the vertical movement than for other previously known service crane constructions, even those that had the vertical movement performed by the actuator.
The invention is presented in the example of the execution in the drawing, in which Fig.1 presents the davit from the first example mounted on the service platform of the operated device located at sea, a tower of a windmill, Fig. 2 presents, in a close-up view, the details of the davit's structure within the solebar, in a fragmented view, before assembling in a whole, Fig. 3 shows the crane from the second example, in a vertical rest position, from a distance, Fig. 4 shows the construction details of the crane from the second example in close-up, the construction is put together and the load is picked up by the crane, Fig. 5 shows the construction details of the crane within the solebar from of the second example in close-up, the structure is fragmented, and Fig. 6 presents the construction used in both the davit and the crane in the vicinity of the solebar, in both examples in a fragmented view from the rear of the crane, while Fig. 7 shows the element used in both, the davit and the crane in the vicinity of the complementary element of the solebar, in both examples in a fragmentation view.

Example one.

An exemplary service crane 1 in the type of a davit 1' is permanently attached by the base 2 to the ground 3, where the ground 3 is the service platform of the serviced device, and also being equipped with the control system 4 and the extension arm 5, has ensured, thanks to the motor 6 of the horizontal rotation, the mobility of the bearing plate 7 connected to the base 2 rotationally and slidingly. The extension arm 5 at one end is attached to the bearing element 8 mounted on the bearing plate 7, where the bearing element 8 and the bearing plate 7 constitute together the main elements 9 of the solebar 10, while at the other its end the extension arm 5 is equipped with a head 11 with a reel 12, on which is supported the working rope 13 passing through the extension arm 5 up to the winding drum 13 one way and to the hook 14 the other way. The extension arm 5, having a blockade of the vertical movement, which is two pins 15a, 15b in an articulated joint 16 permanently attached to the bearing plate 7 at its front edge, connects also to the solebar 10 directly at the next two support points with a pin17a, 17b set in the eye articulation joint 18 at the top of the bearing element 8 of the solebar 10.
The articulated joints 16.18 in an amount of two are in the upper zone 19 of the solebar 10 and in the lower zone 20 of the solebar 10, the articulated movement is blocked by pins 15a, 15b, 17a, 17b. The complementary element 21 of the solebar 10 is a light bar structure 21' made in the form of two placed oppositely to each other steel stays 21a, 21b, in the form of steel plates with a shape similar to a triangle with rounded corners, which are fixed permanently but detachably to the bearing element 8 of the solebar 10 and to the bearing plate 7 of the solebar 10.
Between the steel stays 21a, 21b, is fixed to them a winding drum 22 permanently but detachably through a spherical roller bearing 23 and a gearbox 24 equipped with a slip clutch 25, where inside the winding drum 22 there is a slip clutch 25 with the gearbox 24, which slip clutch 25 with the gearbox 24 connects the winding drum 22 to its driving motor 26. The driving motor 26 is located just behind one of the steel stays 21a, while the horizontal rotation motor 6 is located between the bearing pillars 27 constituting the rear bearing element 8 of the solebar 10. At the same time, the extension arm 5 having a framing construction, on the edge of each rod 5' of its framing construction has an eye element 28 of the articulated joint 16,18, where the eye elements 28 with their outline form the base 29 of the extension arm 5, which base 29 of the extension arm 5 for the extremely lowered position of the extension arm 5 is arranged at an acute angle to the horizontal, having two support points connecting the extension arm 5 with the solebar 10 (which have already been mentioned), each time in the form of a pin 15a, 15b mounted in an articulated eye joint 16 located in the front lower zone 20 of the solebar 10 at its edge.
The horizontal rotation motor 6 is connected to the bearing plate 7 through a gear 30, from which the first gear wheel 31 is permanently attached to the base 2 located from its extreme upper side, and the second gear wheel 32 is axially connected to the horizontal rotation motor 6 set with the gearbox 33 in the solebar 10, the second gear wheel 32 is located from the underside of the bearing plate 7 of the solebar 10. The bearing plate 7 of the solebar 10 is connected with the base 2 slidingly through bearing, by a bearing 34 at the top of the tubular base 2. The driving motor 26 of the winding drum 22 is located on the extension of the axis of the winding drum 22. The horizontal rotation motor 6 is detachably attached to the solebar 10 and is located on the edge of the bearing plate 7 of the solebar at the rear of the solebar 10. The bearing element 8 of the solebar 10 consists of two bearing pillars 27 made of rolled profiles. The extension arm 5 has reinforcements located in the immediate vicinity of the eye elements of the articulated joint 16,18 at the edge of each rod 5' of the framing construction. The extension arm 5 has a blockade of the vertical movement (what has already been mentioned) and connects with the solebar 10 directly at four support points each time with a pin accordingly 15a, 15b, 17a, 17b set permanently in an articulated eye joint 16,18 accordingly, where the articulated joints 18 in the amount of two are located in the upper zone 19 of the solebar 10 at the top of the bearing element 8, and the other articulated joints 16 in an additional amount of two are located in the front lower zone 20 of the solebar 10 at its edge. The release and winding of the working rope 13 is controlled by the control system 4 with the signal of the current overload of the working rope 13 or by the slip clutch 25 due to its overload, wherein the control system 4 is coupled by a remote overload sensor 35 of the working rope 13 with the slip clutch 25 of the winding drum 22 and with the gearbox 24 of the winding drum 22. The crane 1,1' is controlled from a portable cassette 36, with which it may also be forced the manual loosing of the working rope 13as a result of switching off the driving motor 26 and its brake.
The head 11 with the reel 12 attached to the top of the extension arm 5 is a maintenance-free head, and the overload sensor 35 of the working rope 13 is located at a considerable distance from the head 11 and equipped with a radio connection is located at the contact of the working rope 13 and swivel 45 and the hook 14 of the working rope 13, as a demountable equipment.

Example two.

As in the first example with the following differences.
The service crane 1 is like a 1" crane. The extension arm 5 has the function of vertical movement and connects to the solebar 10 directly at two support points each time with a pin 17a, 17b permanently mounted in the articulated eye joint 18 in the upper zone 19 of the solebar 10 at the top of the bearing element 8, and also connects to the solebar 10 indirectly through the actuator 37 and two support points each time with a pin 15a, 15b permanently fixed in the articulated eye joint 16, whereby the other two pins 15a, 15b are an extension of the clamping ring 38 catching the cylinder 39 of the actuator 37, which end of the piston rod 40 is attached with an additional fifth pin 41 in the additional fifth articulated joint 42 located in the front lower zone 20 of the solebar 10 at its edge. The front edge of the solebar 10, i.e. the bearing plate 7, has no other articulated joints or eyelets to which any pin would fit in the same way as in the davit 1 'of the first example.
The cylinder 39 of the actuator 37 is then hidden inside the framing construction of the extension arm 5, where the extension arm 5 is attached to the bearing element 8 pivotally, and the pivoting movement is realized on the two articulated joints 18 located at the top of the bearing element 8 of the solebar10, on pins 17a, 17b. Then in the position of the actuator 37 with the piston rod 40 fully extended - the position of the extension arm 5 is close to vertical, and in the position of the actuator 37 with the piston rod 40 fully retracted the position of the extended arm 5 is close to horizontal The actuator 37 has an electro-hydraulic drive, and the electric motor 43 of the electro-hydraulic drive is attached to cylinder 39 of the actuator 37 and is hidden together with the actuator 37 inside the lattice construction The clamping ring 38 catching the cylinder 39 of the actuator 37 is located at the base of the cylinder 39, i.e. on the opposite side of the bottom 44 of the cylinder 39. Such mounting of the cylinder 39 of the actuator 37 causes that its cylinder 39 does not participate in the extension of the extension arm 5 from the bearing plate 7 of the solebar 10, what causes faster vertical movement of the extension arm 5 without loss of linearity of movement of the piston rod 40 in the actuator 37 as time passes.
In both examples, due to the construction and arrangement of elements relative to each other, it is possible a fuller operation with the extension arm 5 and, what is unexpected - the crane1 is more compact and needs less space for its foundation. The crane 1 is also lighter due to the lattice construction, and what is related to this, needs less drives with less power for its own movement, with simultaneous optional selection of drive for operating the working rope 13. There is an easy access to the low lowered extension arm 5, even from the position of the operator standing on the service platform. There is no problem with the replacement of elements, there is no problem with servicing the crane 1 itself. At the time when the crane 1 is not used for a long time, it can be covered without excessive effort, e.g. with a tarpaulin, or, after removing the cover, cleaned and lubricated.
Due to the design of the winding drum 22 with the placed inside slip clutch 25 and the gearbox 24 p, which are all placed inside the solebar 10 and communicate remotely with the overload sensor 35 of the working rope 13, in the device there is an automatic overload protection system. As a rule, it is known that in case of an overload, the rope must be released from the winch 22 in order to protect the device against damage. The value at which this occurs is dependent on a number of factors such as: capacity, lifting speed, rigidity of the structure, efficiency of the device mechanisms, materials used, accuracy of performance. In our embodiments, as a destructive value is considered a force exceeding 300% of the nominal capacity of the device, which for an example davit 1' with a capacity of 2t, this force is converted to approx. 60kN, while due to the occurrence of time delay and the dynamics of the phenomenon, to preserve the safety, the trip activation , i.e. the moment of occurrence of a slip of the slip clutch 25, is set so that in any moment the force does not exceed 240% of the nominal force, which means for the considered examples that this force is about 48kN. This is due to the European standard for the design of offshore cranes EN13852-1:2013, which allows the occurrence of a force not exceeding 80% of the destructive force. When an overload occurs due to an external force exceeding the allowable value, occurs the slip of the slip clutch 25 slips, which is located between the motor shaft 26 and the input shaft of the gear 24 of the winch 22. It is a friction clutch that, by regulating the pressure of the friction discs, is able to transfer and maintain the right torque. The torque value changes proportionally to the set pressure force of the discs on the clutch. The slip occurs when a torque is of 290Nm on the clutch. During the slip, it is still transmitted a torque of 180Nm. The estimated time from exceeding the allowable load to the moment of slip (i.e. until the activation of the system) is dependent on the dynamics of action of the external factor causing this overload - in our examples, the response time of the system is of about 0.2s to 1s. Despite the occurrence of the slip, the winch 22 must be able to release a rope tensioned with a specific force, corresponding in our case to 150% of the nominal capacity - for the examples considered, this force is of about 30kN. The load is thus secured against an uncontrolled lowering, which could generate a danger persons and structures nearby. The nominal lifting speed depends on the required regulations and standards, the wave height at which the work is allowed and the type of delivery unit. For example, according to European standard 13852-1 for operation at 2m wave, the lifting speed is of 36m /min. However, when switching on the overload protection system, the speed with which the winch 22 must be able to release the rope is of 72m / min, i.e. double value of the nominal speed. The time of unwinding the rope 13 is limited by the time in which will be released the entire rope 13 located on the winding drum 22 and ripping it out of its fastening holders or due to the loss of an external force. The fastening of the rope 13 is also designed so that the above mentioned destructive force referred couldn't damage any component of the device, only the rope 13 was ripped out of it. Assuming that when lifting the load, the amount of rope 13 wound on the winding drum 22 is 15m, then the operation time of the AOPS system will be at least of 12.5 seconds. When the overload ceases to occur faster than the full unwinding of the rope 13, then the device returns to the normal configuration of the work. The system, due to its nature, activates and deactivates automatically, and the simplicity of operation gives greater reliability and faster response time comparing to the commonly used electro-hydraulically controlled solution, in which the release / winding of the rope is permanently corrected due to the results obtained from the overload sensor. Due to the complicated hydraulic-mechanical system (with valves) of earlier solutions, the response time to overload of the working rope was even longer by 3s, which could increase the dynamic force even by 20-25% higher than in case of the solution according to the invention with a slip clutch 25.

Claims

The service crane is permanently attached with the base to the ground, and also, being equipped with a control system and an extension arm, has assured, thanks to the horizontal rotation motor, mobility of the bearing plate connected with the base rotationally and slidingly, wherein the extension arm at one its end is attached to the bearing element fixed on the bearing plate, together constituting the main elements of the solebar, while at its other end the arm is equipped with a head with a reel on which is supported a working rope running through the extension arm up to the winding drum in one direction and to the hook in the other direction, and the extension arm, possibly having a blockade of the vertical movement, connects with the solebar at least indirectly at least at two support points, preferably with a pin embedded in the articulated eye joint, where the articulated joint in the amount of at least one is in the upper zone of the solebar, characterized by that the complementary element (21) of the solebar (10) is a light bar structure (21 ') made in the form of two placed oppositely to each other steel stays (21a, 21b), preferably in the form of steel plates, which are fixed preferably detachably to the bearing element (8) of the solebar (10) and to the bearing plate (7) of the solebar (10), where between the steel stays (21a, 21b) is mounted detachably the winding drum (22), inside of which there is a slip clutch (25), preferably with the gearbox (24), which slip clutch (25) with the gearbox (24) connects the winding drum (22) with its driving motor (26), which driving motor (26) is located just behind one of the steel stays (21a), while the motor (6) of the horizontal rotation is located between the bearing pillars (27) constituting the rear bearing element (8) of the solebar (10), as well as the extension arm (5) having a framing construction, at the edge of rod (5 ') of its framing construction has an eye elements (28) of the articulated joint (16.18), where the eye elements (28) with their outline form the base (29) of the extension arm (5), which base (29) for the extremely lowered position of the extension arm (5) is laid at an acute angle to the horizontal having the second two support points connecting the extension arm (5) with the solebar (10), each time in the form of a pin (15a, 15b) embedded in the articulated eye joint (16) located in the front lower zone (20) of the solebar (10) at its edge.
The service crane according to claim 1, characterized by that the motor (6) of the horizontal rotation is connected to the bearing plate (7) through a gearbox (30), from which the first toothed gear (31) is permanently attached to the base (2) located from its extreme upper side, and the second toothed gear (32) is axially connected to the motor (6) of the horizontal rotation mounted in the solebar (10), the second toothed gear (32) is located from the bottom side of the bearing plate (7) of the solebar (10).
The service crane according to claim 1 or claim 2, characterized by that the bearing plate (7) of the solebar (10) is connected to the base (2) slidingly by bearing.
The service crane according to claim 1, characterized by that driving motor (26) of the winding drum (22) is located on the extension of the axis of the winding drum (22).
The service crane according to claim 1, characterized by that the motor (6) of the horizontal rotation is detachably attached to the solebar (10) and is located on the edge of the bearing plate (7) of the solebar (10) at the rear of the solebar (10).
The service crane according to claim 1, characterized by that bearing element (8) of the solebar (10) are bearing pillars (27) made of rolled profiles.
The service crane according to claim 1, characterized by that the extension arm (5) has reinforcements located at least in the immediate vicinity of the eye elements (28) of the articulated joint (16,18) at the edge of each rod (5') of the framing construction.
The service crane according to claim 1, characterized by that the extension arm (5) has a blockade of the vertical movement and connects to the solebar (10) directly at four support points each time with a pin (15a, 15b, 17a, 17b) permanently fixed in the articulated eye joint (16.18), where the articulated joints (18) in the amount of two are in the upper zone (19) of the solebar (10) on the top of the bearing element (8), and the other articulated joints (16) in the amount of two are in the front lower zone (20) of the solebar (10) at its edge.
The service crane according to claim 1, characterized by that the extension arm (5) has the function of the vertical movement and connects with the solebar (10) directly at two support points each time with a pin (17a, 17b) permanently embedded in an articulated eye joint (18) in the upper zone (19) of the solebar (10) at the top of the bearing element (8), and also connects with the solebar (10) indirectly through the actuator (37) and two support points each time with a pin (15a , 15b) permanently embedded in the articulated eye joint (16), and the other pins (15a, 15b) are an extension of the clamping ring (38) catching the cylinder (39) of the actuator (37), which end of the piston rod (40) is attached with an additional pin (41) in an additional one articulated joint (42) located in the front lower zone (20) of the solebar (10) at its edge, while the cylinder (39) of the actuator (37) is hidden inside the framing construction of the extension arm (5), where the extension arm (5) is attached e to the bearing element (8) pivotally.
The service crane according to claim 9, characterized by that in the position of the actuator (37) with the piston rod (40) fully extended, the position of the extension arm (5) is close to vertical.
The service crane according to claim 9, characterized by that in the position of the actuator (37) with the piston rod (40) fully retracted, the position of the extension arm (5) is close to horizontal.
The service crane according to claim 9 or claim 10 or claim 11, characterized by that the actuator (37) has an electro-hydraulic drive, and the electric motor (43) of the electro-hydraulic drive is attached to the cylinder (39) of the actuator (37) and is hidden together with the actuator (37) inside the lattice construction.
The service crane according to claim 9, characterized by that the clamping ring (38) catching the cylinder (39) of the actuator (37) is located at the base of the cylinder (39) that is on the opposite side of the bottom (44) of the cylinder (39).
Service crane according to any of claims from claim 1 to 13, characterized by that the release and winding of the working rope (13) is controlled by a signal of the current overload of the working rope (13), whereby the control system (4) is coupled through the remote overload sensor (35) of the working rope (13) with a slip clutch (25) of the winding drum (22) and / or with the gearbox (24) of the winding drum (22).
The service crane according to claim 1 or claim 14, characterized by that is controlled from a portable cassette (36).
Service crane according to any of claims from the claim 1 to 15, characterized by that the head (11) with the reel (12) mounted on the top of the extension arm (5) is a maintenance-free head, whereby the overload sensor (35) of the working rope (13) is located far from the head (11), preferably equipped with a radio link is located at the contact of the working rope (13) and the swivel (45), alternatively the hook (14) of the working rope (13) as a removable equipment.
The service crane according to claim 9, characterized by that ground (3) is the service platform of the serviced device.