EP1879827B1 - Sling device for a piece with force compensation and hoisting system comprising the same - Google Patents

Abstract

A slinging device for a piece includes a sling with a nonextensible part and a section with a spring device, enabling an elastic lengthening or shortening of the sling under load by a limited amplitude in response to a limited change in the load on the piece, the device including a frame and a floating support, the spring device holding the floating support in the absence of application of force to the piece along a vertical axis, in a position of equilibrium centered vertically with respect to the frame under the weight of the piece, and a way for regulating and adapting the position of equilibrium of the floating support depending on the weight of the piece.

Description

The present invention relates to a device for slinging a workpiece with force compensation according to the preamble of claim 1, in particular adapted to be used with a lifting system such as a traveling crane or crane supporting slung parts, as well as a system lifting device comprising it. Such a device is known to US 4121806 A .

In the context of the positioning of heavy elements such as structural elements of a device to be assembled, it is common to use as lifting systems cranes suspended from structures of a hangar or fixed or mobile cranes .

Such lifting systems are intended for the handling of mass elements frequently from a hundred kilos to several tens of tonnes carried by a sling while offering a high accuracy in positioning along a vertical axis and a horizontal plane as it is usual when assembling elements of buildings, ships, aircraft or other devices such as electric generators.

They are used as machine tools to obtain a positioning accuracy of less than a millimeter or 1/10 of a millimeter so that the elements can be connected in a very precise way without causing any stress or damage to the structures to be used. connected.

A first difficulty in maintaining the positioning accuracy along the vertical axis is that the lifting systems or means, because of their mass and the mass they lift, carry and move, produce a load on the supporting structures. that can generate displacements of these structures or their foundation.

When only one lifting means is used, the movements of the load-bearing structures under the effect of its own movements are not penalizing, on the other hand, when several lifting means are integral with one and the same load-bearing structure, moving or loading one of the lifting means can cause a variation of positioning of another lifting means. Measurements carried out on complexes of two traveling cranes have revealed induced movements of up to a few millimeters, at speeds of the order of 0.25 mm / s.

In the case where the displacement of a first lifting means such as a bridge takes place during an assembly operation, on a fixed element, of an element carried by a second bridge, the height variations of the second bridge due to the displacement of the first bridge are detrimental to the precise connection of said elements during assembly.

Another difficulty, independent of the number of lifting means, is that said means or structures to which they are attached are sensitive to the wind.

Indeed, the winds exert constraints on the structures carrying assembly hangars, for example assembly hangars of large aircraft such as induce bending of said load-bearing structures causing vertical movements of the winches up to a few centimeters.

The combination of the effects of wind and the effects of interferences between lifting means can cause significant damage to the elements being assembled if it results in a vertical displacement of a supported element relative to a ground-based structure. which it is being edited.

For example, a lifting of the order of 50 mm of an element being assembled on a fixed element may cause a break in the sling, if the element being assembled is already at least partially fixed to the fixed element, or very important damage to the carried element or the fixed element.

A known solution consists in using a dynamic system for controlling the position of the traveling cranes as a function of displacements of the carrying structure and for controlling the winches of the lifting means accordingly.

Such a solution is not satisfactory because of the complexity of the system to be implemented: control devices, sensors, control means in position also requiring for their operation high instantaneous electric powers.

The present invention starts from another principle which is to limit the dynamic forces at the level of the connection of the winch with a part being assembled and for this purpose it is proposed to compensate the forces applied to the suspended part by an elongation or a narrowing of the sling between the winch and the workpiece under the simple effect of dynamic forces on the part being assembled.

The invention thus makes it possible to compensate for variations in height, induced by the movements of the carrying structure, by lengthening or narrowing of the sling, in the case where the part is already being assembled or when a resistant force opposes the movement of the slinged piece.

To do this, the present invention relates to a device for slinging a part, characterized in that it comprises a sling with the features of claim 1.

Thus, according to the device of the invention, a movement of the carrier structure downwardly along the vertical axis tending to descend the part will be compensated by a reduction in the distance of the piece to the winch, in case the piece comes in abutment against a fixed element relative to the ground, in a predefined range, so that the force that the part applies to the fixed element is kept below a limit value low enough not to cause damage on the part handled, on the fixed element or on any other element related to the part and to the fixed element or arranged between the part and the fixed element.

Likewise, a movement of the carrier structure upwards along the vertical axis tending to lift the part will be compensated by an increase in the distance of the piece to the winch, in a predefined range, in case the piece is totally or partially assembled to a fixed element with respect to the ground, so that the force that the part applies to the fixed element and the assemblies is kept below the limit value in order to avoid any similar damage.

The invention, which comprises load compensating means varying the distance of the winch piece in response to a force applied to the workpiece along said vertical axis, allows a positioning retraction of the part suspended from a winch by a suspension cable. along the vertical axis.

Advantageously, the device comprises means for adjusting the amplitude of the elongation and the shortening of the sling as a function of the load (F1, F2). These means make it possible in particular to adapt the device to parts to be handled with different mass.

More particularly, the spring means are part of a load compensating device, changing the distance from the workpiece to a winch to which the sling is connected in response to a force applied to the workpiece along the vertical axis of the sling, constituted by a frame, a floating support and said means now leaves the floating support, in the absence of application of force on the part along the vertical axis, in a position of equilibrium centered vertically with respect to the built under the weight of the room.

en figure 1:

une vue de côté d'un dispositif d'élinguage selon l'invention;

en figures 2A et 2B:

Des vues schématiques de face du dispositif selon l'invention respectivement sous charge en traction et sous charge en appui;

en figure 3:

une vue de côté en perspective d'un exemple de réalisation d'un dispositif compensateur de charge selon l'invention;

en figure 4:

des vues de détail en perspective coupe d'éléments du dispositif de la figure 3;

en figure 5:

le dispositif de la figure 3 en vue de côté;

en figure 6:

une vue de côté en coupe d'un balancier du dispositif compensateur de la figure 2.

en figures 7A, 7B et 7C:

des vues de côté de détails de réalisation d'un dispositif selon l'invention.

Other characteristics and advantages of the invention will be better understood on reading the following description of a nonlimiting exemplary embodiment of the invention with reference to the figures which represent:

in Figure 1:

a side view of a sling device according to the invention;

in FIGS. 2A and 2B:

Diagrammatic front views of the device according to the invention respectively under load in tension and under load in support;

in Figure 3:

a perspective side view of an exemplary embodiment of a load compensating device according to the invention;

in figure 4:

detailed perspective cut views of elements of the device from the figure 3 ;

in Figure 5:

the device of the figure 3 in side view;

in Figure 6:

a side view in section of a balance of the compensating device of the figure 2 .

in FIGS. 7A, 7B and 7C:

side views of embodiment details of a device according to the invention.

The slinging device according to the figure 1 comprises a winch 2 moving on a rail and supporting a part 1 held by a sling 3.

The winch moves on the rail according to a control device not shown because traditional. Similarly, the sling can be shortened or lengthened by the winch so as to position the supported piece in front of a floor structure on which it must be assembled.

In practice, this winch can be replaced by any device for lifting a load by means of a sling.

According to the invention, the sling 3 is provided with a first non-extensible portion 3a above a section 3c provided with spring means 10, 10 'allowing, under load, elongation or elastic shortening of a given amplitude. limited the sling 3 in response to a limited determined variation of the load on the part 1. The sling according to the example shown is further provided with a second non-expandable portion 3b below the section 3c.

The spring means 10, 10 'are part of a load-compensating device 4, changing the distance of the workpiece to the winch 2 to which the sling 3 is connected, in response to a force F1, F2 applied to the workpiece according to the invention. vertical axis A1 of the sling 3.

It will be noted that in the absence of a compensating device, the force F1 is equal to the forces exerted on the sling in its part related to the winch and the supporting structure, these efforts, uncontrollable by nature, may exceed the capacities of the sling and that the force F2 is equal to the weight of the part to be assembled.

The compensating device consists mainly of a frame 5, a floating support 6 and said spring means 10, 10 '.

The spring means maintain the floating support 6 in a position of equilibrium, preferably a position for which the floating support 6 is centered vertically with respect to the frame 5 under the weight of the piece 1 in the absence of application of force on the part along the vertical axis A1.

A schematic example of operation of the preferred device according to the invention is described in Figures 2a and 2b .

As indicated above, this embodiment aims to limit the forces on the part and on the ground structure in the case of a vertical displacement of the winch caused by a deflection of the bearing structure either downwards or towards the high.

The frame 5, the floating support 6 and the spring means 10 constitute a deformable system at equilibrium under the action of the weight of the part. At equilibrium, the system is advantageously adjusted so that the floating support is centered vertically with respect to the frame 5.

According to figure 2a the supporting structure undergoes an elevation E which drives the winch upwards.

The piece raises and abuts against an element of the structure on the ground S. As the part is stopped by the structure S, a force F1 is transmitted to the compensating device 4 through the floating support which is pulled down. Under this force, the spring 10 undergoes, in the proposed exemplary embodiment of a compression spring, a compression force C1, C2 and is compressed thereby allowing the floating support 6 to descend relative to the frame 5 which limits the the force applied by the part on the structure.

According to figure 2b , the bearing structure undergoes a subsidence A.

When the piece comes to the bottom stop, the structure S applies a counter-reaction force F2 to the part, the traction on the movable support decreases which relaxes the spring 10 and raises the movable support 6 to reduce or limit the force of support of the piece on the structure.

As will be seen later with reference in particular to the figure 6 , the slinging device comprises means 16, 16 'for adjusting the amplitude of elongation and shortening of the sling 3 as a function of the elongation and the shortening of the spring means 10 so as to be able to adjust the midpoint of the floating support 6 depending on the weight of the part 1 to wear.

An example of the device is shown in more detail at figure 3 .

The frame 5 comprises a body provided with front faces of which only parts 20a, 20b, 20c, 20d at the axis of the elements of the device are shown and a rear face 19. The floating support 6 is mounted in the interior space defined by the front and back faces.

According to the invention, one of the frame 5 and the floating support 6 is provided with an upper end 7 connecting to a non-extensible part 3a of the sling 3, the other being provided with a lower end provided with means 7 'retaining the suspended part.

According to the example shown, it is the frame 5 which is connected to the non-extensible top portion 3a of the sling by its upper end 7, the floating support 6 being provided with means 7 'for retaining the suspended part.

To allow extension or retraction of the sling, the floating support 6 is slidably mounted in the frame 5 along the vertical axis A1 between guide means 8, 8 ', 9, 9'.

The guide means 8, 8 ', 9, 9' comprise at least one vertical rack 8, 8 'integral with the floating support 6 meshing with a first pinion 9, 9' offset relative to the floating support 6 on a perpendicular axis vertical axis A1.

According to the example and in particular the figure 3 the device is double and symmetrical with respect to a plane passing through the axis A1 and perpendicular to the rear face 19 of the frame, the guide means 8, 8 ', 9, 9' being symmetrical with respect to said vertical axis A1, on either side of the floating support 6. A configuration of the device for which the floating support 6 comprises a single vertical rack and is sliding on the opposite side to the rack on a vertical rail is of course conceivable according to the invention.

The guide means therefore comprise at least one rack 8 and a pinion 9, meshing with the rack 8 and having an axis of rotation 25 secured to the frame 5, perpendicular to said vertical axis A1 and to the front and rear faces of the frame, for allow a vertical displacement of the floating support in the frame.

According to the example, the spring means 10, 10 'for their part are integral with an arm 15 of a rocker 11 mounted on a shaft 12 secured to the frame 5 and parallel to the axis of rotation 25 of the pinion 9, 9 .

To adapt the device to a given range of forces, the spring means 10, 10 'are connected to the floating support 6 through a reduction device comprising said first pinion 9, 9', gear means 13, 13 ', 14, 14' rotating the balance 11, 11 'in a given angular sector.

In an exemplary application, the device is set to limit the force between the piece 1 and the ground structure to a value of 2% of the nominal load for a load of between 2000 daN and 5000 daN and uses as spring means 10 gas springs of known technology.

It is possible to modify the operating range, in particular the value of the maximum forces when the device reaches the mechanical stop, by adapting the characteristics of the spring means used.

According to the example, a setting of an equilibrium position of the device is provided.

The symmetrical device comprises two rockers driven in rotation in opposite directions around shafts 12, 12 'integral with the frame during vertical displacements of the floating support 6 relative to the frame 5 and the spring means 10, 10' are suspended by their two ends between the arms of the rockers 11, 11 '.

During the vertical movements of the floating support under the action of a load variation at the workpiece 1, the reduction devices, symmetrical with respect to the vertical axis A1, comprising the first pinion 9 and 9 'and means gear 13, 13 ', 14, 14' drive the rocker 11, 11 'in rotation in opposite directions on a given angular sector.

Thus the application of a load F1, F2 on the part causes a displacement of the floating support 6 driving the arms 15, 15 'in rotation in the opposite direction until a new equilibrium position of the floating support 6 is obtained. the action of the spring means 10, 10 'constrained in compression or extension in the direction of the load F1, F2 applied to the workpiece.

To allow a lever effect, the rockers 11, 11 'are hinged to the frame on the shaft 12 at a first end of the arms 15, 15' and each secured to this end of a gear element 14, 14 'driven by one the symmetrical gearing devices and oriented perpendicular to the arms.

A view of a pendulum is represented in figure 4 , this figure representing the elements of the reduction device comprising the racks 8, 8 'on the floating support 6, one of the pinions 9, 9' meshing with the racks, this pinion 9 being coaxial with a gear ring 13 actuating the gear element 14 of the balance 11.

To receive the ends of the spring means 10, 10 ', the arms 15, 15' each receive a movable support 17, 17 'supporting the spring means 10, 10' and are provided with adjustment means 16, 16 'in the form of a worm 21, operated by a wheel 16, 16 ', receiving the movable support 17, 17'.

These adjustment means make it possible to balance the device as a function of the mass of the piece 1 to give the arms a similar amplitude of movement in both directions (clockwise and counterclockwise).

Although this is not essential to the operation of the device, it is advantageous to provide by construction that the two arms 15, 15 'are parallel when no load is applied to the hook 7'.

This arrangement makes it possible not to compress the spring means 10, 10 'when adjusting the position of the movable supports 17, 17', which makes it possible to adjust without particular effort on the means 16 and 16 '.

According to a preferred setting, the movable supports 17 and 17 'have identical positions on the arms 15 and 15' respectively.

The Figure 7A describes drive means 27 connecting the worm 21 of the arms 15 and 15 'and for simultaneously adjusting the position of the movable supports 17 and 17' ensuring identical positioning of these supports in the arms 15 and 15 '.

Such drive means which according to the example are made by shafts and gimbals can according to the invention be made by chains or hoses such a modification remaining within the general knowledge of the skilled person.

An action on the flywheels 16, 16 'makes it possible to move the mobile support 17, 17' along the arm 15 and thus bring the application point closer to or away from the force exerted by the spring means 10, 10 'of the end of articulation of the arms.

Advantageously, the device is designed so that for the position of equilibrium under load the floating support 6 has an upward travel latitude equal to its amplitude of travel downwards between an upper stop 23 and a lower stop 24.

In the application mentioned above, the stops are reached at travel amplitude maxima fixed for example to ± 5 cm around the equilibrium value to take into account the permissible extreme cases of sagging of the bearing structure.

Thus, for any deflection of the carrier structure of lower amplitude, the stress applied by the workpiece 1 on the structure or any element interposed between the workpiece and the structure remains below the value defined above is a load less than 100 daN.

To allow easy adjustment of the equilibrium point according to the mass of the parts 1 to support, needles 22 integral with each movable support 17, 17 'moves in front of graduations 26 on the arms 15, 15'.

Finally so as to avoid oscillations of the parts during the operation of the crane or winch, the device according to the example provides that the spring means 10, 10 'are in parallel with damping means 18, 18'.

In the complementary embodiment, device measuring and / or detecting means 28, 29, 30 are made.

In the case of position detection means, an extreme position detection such as one or more end-of-travel sensors 28 makes it possible to detect whether the force reaches a determined limit.

A device with limit sensors 28 connected to an alarm device 33 is represented in FIG. figure 6 .

The limit switches 28 may be contact, inductive or other.

The Figure 7A represents in particular an embodiment according to which end-of-stroke sensors 28 are disposed facing abutment elements 34, 35 on the mobile part of the device.

In the case where the chosen sensor is a measurement sensor 29 giving a measurement of the position of the mobile part of the device, a potentiometric sensor or an optical encoder can be used without this list being limiting. An example of positioning of a potentiometric sensor is represented in Figure 7C at the end of a shaft for holding a gear element 14.

The sensors are advantageously connected to devices such as alarm devices and / or compensation evolution monitoring, the latter to alert operators in anticipation when, during an assembly operation, an evolution the amplitude of the compensating movements reflects a deterioration of the safety conditions.

The detection, before reaching the physical stops of the device, a harmful evolution of the amplitude of movement allows to interrupt the assembly operations until the return of secure working conditions.

In this case, the detection sensor or sensors are measurement sensors 29 delivering a signal representative of the real-time position of the mobile element of the device connected to an alarm system comprising means for measuring and monitoring the alarm. evolution of the amplitude of the compensating movements comprising means for detecting the exceeding of a threshold and for generating an alarm on exceeding said threshold.

In the case where the sensor or sensors are end-of-travel sensors 28, the alarm system to which they are connected may comprise only a simple detection that the stop is reached or is near to being reached and trigger an alarm on this detection.

According to a simplified version, the detection means consist of markers such as visual indicators 30 on at least one of the parts in relative motion as shown in FIG. Figures 7B, 7C .

For example, the rod 31 connected to the hook 7 'which slides in the guide 24 may have in its upper and lower parts color indicators which will appear or disappear under the guide 24 before the device reaches a mechanical stop.

Advantageously, these indicators 30 are arranged on a flattened recess on the cylindrical rod to avoid any risk of erasure by wear during sliding of the rod in the guide.

Equivalently, visual witnesses 30, such as those shown in FIG. Figure 7C facing an index 32, on the pinions or the arms are possible according to the invention.

The invention further comprises a lifting system such as a crane or a traveling crane comprising a two-part sling 3a and 3b between which is disposed a device according to claim 1.

The invention is not limited to the example shown and in particular an asymmetrical device for which one end of the spring means is integral with the frame is possible according to the invention. In addition, depending on the desired characteristics for the range of movement of the hook and allowable forces, it is possible to adapt the dimensions and the number of stages of gears conjugating the movement of the arms 15, 15 'with that of the support floating 6.

Claims (21)

1. Device for slinging a component (1), characterized in that it comprises a sling (3) provided with a non-extensible part (3a, 3b) and with a section (3c) equipped with spring means (10, 10') which, under load, allow the sling (3) an elastic lengthening or shortening by a set limited amount in response to a set limited variation in the load on the component (1), comprising a framework (5) and a floating support (6), the said spring means (10, 10') in the absence of load applied to the component along the vertical axis (A1) keeping the floating support (6) in a position of equilibrium with respect to the framework (5) under the weight of the component (1), characterized in that the spring means (10, 10') are secured to an arm (15) of a balance beam (11) mounted on a shaft (12) secured to the framework (5) and perpendicular to the said vertical axis (A1) and are connected to the floating support (6) via a step-down device (8, 8', 9, 9', 13, 13', 14, 14').
2. Device according to Claim 1, characterized in that it further comprises means (16, 16') for adjusting and adapting the position of equilibrium of the floating support according to the weight of the component.
3. Device according to Claim 1, characterized in that it comprises a framework (5) and a floating support (6), the spring means (10, 10') holding the floating support and forming part of a load-coznpensating device (4), modifying the distance from the component to a wench (2) to which the sling (3) is attached in response to a force (F1, F2) applied to the component along the vertical axis (A1) of the sling (3).
4. Device according to Claim 2 or 3, characterized in that, of the framework (5) and the floating support (6), one is provided with an upper end (7) for connecting to a non--extensible part (3a) of the sling (3), the other having a lower end provided with means (7') of retaining the suspended component, the floating support (6) being mounted such that it can slide in the framework (5) along the vertical axis (A1) between guide means (8, 8', 9, 9').
5. Device according to Claim 4, characterized in that the guide means (8, 8', 9, 9') comprise at least one vertical rack (8, 8') secured to the floating support (6), meshing with a first pinion (9, 9') which is offset from the floating support (6) on an axis perpendicular to the said vertical axis (A1).
6. Device according to any one of the preceding claims, characterized in that the step-down device comprises the said first pinion (9, 9') and comprises gearing means (13, 13', 14, 14') that rotationally drive the balance beam (11, 11') over a given angular sector.
7. Device according to Claim 4, characterized in that the guide means (8, 8', 9, 9') are symmetric about the said vertical axis (A1) on each side of the floating support (6).
8. Device according to Claim 7, characterized in that the spring means (10, 10') are suspended by their two ends between the arms of the balance beams (11, 11'), and in that step-down devices, symmetric about the vertical axis (A1), connect the balance beams (11, 11') to the guide means so that the application of a load (F1, F2) to the component causes the floating support (6) to move, driving the arms (15, 15') in rotation in opposite directions until the floating support (6) reaches a new position of equilibrium.
9. Device according to Claim 8, characterized in that the balance beams (11, 11') are articulated to the framework at a first end of the arms (15, 15') and are each secured at this end to a gearing element (14, 14') driven by one of the symmetric step-down devices and directed at right angles to the arms.
10. Device according to Claim 8 or 9, characterized in that the arms (15, 15') each comprise a mobile support (17, 17') accepting the spring means (10, 10') and adjusting means (16, 16') for moving the mobile support (17, 17') and moving the point at which the load exerted by the spring means (10, 10') is applied closer to or further away from the articulation end of the arms.
11. Device according to Claim 10, characterized in that the floating support (6) is centred vertically with respect to the framework (5) under the weight of the component (1) if no load is applied to the component along the vertical axis (A1).
12. Device according to one of the preceding claims, characterized in that the spring means (10, 10') are mounted in parallel with damping means (18, 18').
13. Device according to one of the preceding claims, characterized in that it comprises detection means (28, 29, 30) designed to detect a specific position.
14. Device according to Claim 13, characterized in that the detection means comprise at least one visual indicator.
15. Device according to Claim 13 or 14, characterized in that the detection means comprise at least one position sensor.
16. Device according to Claim 13, characterized in that the position sensor is an end-of-travel sensor (28).
17. Device according to Claim 15, characterized in that the position sensor is a sensor (29) that delivers a signal indicative of the real-time position of the mobile element of the device.
18. Device according to one of Claims 15 to 17, characterized in that the said at least one position sensor (28, 29) is connected to an alarm system (33).
19. Device according to one of the preceding claims, characterized in that the alarm system (33) comprises means for measuring and monitoring the change in amplitude of the compensatory movements, comprising means for detecting the crossing of a threshold and for generating an alarm when the said threshold is crossed.
20. Device according to one of the preceding claims, characterized in that the spring means (10, 10') consist of gas springs.
21. Lifting system, characterized in that it comprises a sling equipped with a slinging device according to one of the preceding claims.

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