EP1232113B1 - Load balancing for a winch with two pull wires and winch equipped with same - Google Patents

Abstract

The invention concerns a load balancing device consisting of a planetary or trochoidal mechanical differential speed reducer, arranged on a winch comprising two drums and enabling to balance the torque exerted on the drums. Thus, if a cable is improperly wound on one of th drums, the balancing device enables the tensile load exerted on each wire to remain identical. Such a device is particularly efficient to ensure security for a working platform operating on a building facade.

Description

The present invention relates to a winch provided with a device for balancing tensile forces, particularly intended for wind, respectively unwind two cables of traction or more, as well as nacelle fitted with at least one winch as above.

Such winches, comprising in particular a double means winding, drums or pulleys, each of said means carrying its own cable, find many applications. Particularly for certain configurations, they are used for elevators or more particularly for nacelles responsible for cleaning and / or maintaining the facades of tall buildings. Such a nacelle is generally supported by four cables, one first pair of cables being arranged on a first narrow side of the nacelle while the second pair of cables is placed on the second narrow side of the nacelle. Each pair of cables is wound / unwound from a winch with two drums, each winch with its own motor controlled independently of the other. The winding / unwinding speed adjustment of each winch is done therefore by mechanical, electrical or electronic means known to so that each pair of cables unrolls or winds itself speed so that the basket remains horizontal. However, for both cables of a determined pair, since their winding speed or unwinding is controlled by a single winch, respectively by only one engine, the means mentioned cannot be implemented to keep their balance. An imbalance between the two cables of a pair can occur for example in the case of a winding irregular of one of the cables on its drum, leading to a winding subsequent turns on a diameter larger than that around which wraps the other cable. In this case, the cable winding on a stronger diameter will tend to take up all the tensile force, which can lead to an imbalance in the nacelle, or even to endangering the personnel mounted in this nacelle by rupture of this overloaded cable.

A first mechanical means to maintain a identical tensile stress on the two cables of the same pair, even if one of the cables is wound incorrectly, consists of join the two cables on a pulley. Such a device can be dangerous in case of breakage of one of the cables since then the other cable becomes free and the basket is no longer retained by any of the two cables.

Alternatively, the two cables are attached to the two ends of a lifting beam, the center of this being fixed so swivel to the suspension beam or to the nacelle. This device does not does not meet the aforementioned drawback, but on the other hand the difference in admissible length between the two cables is limited by the length of the lifter.

In the two means described above, the attachment of the device balancing, pulley hub or spreader center, done in one single point, on the nacelle or on the suspension beam, which is ultimately harmful to the balance of the nacelle.

FR-A-2.183.594 describes a differential device for a crane lifting winch. By this device, the operator controls sequentially, and not simultaneously, a lifting operation and a telescoping operation of the masts. It is only indicated nowhere in this document does the device allow simultaneous actuation of two drums.

WO88 / 05999 describes a differential device making it possible to balance the forces on two tow cables for a trawl. The document expressly describes that the trawl launching and lifting operations are carried out without the use of the differential device, which is only activated during the fishing, either when the winches are inactive.

An object of the invention is to propose a winch intended for at least one pair of traction cables fitted with at least one device balancing force capable of ensuring the security of the object at all times hanging on cables.

Yet another object of the invention is to provide a nacelle of maintenance of facade provided with at least one winch equipped with a device balancing of efforts.

These goals are achieved by a winch and a nacelle with the characteristics mentioned in the independent claims, specific forms of execution or variants being described in the dependent claims.

la figure 1 est une vue en élévation d'une portion d'une installation de nettoyage de façade,

la figure 2 est une vue en bout d'une portion de l'installation de la figure précédente,

la figure 3 est une vue en coupe longitudinale d'une première forme d'exécution d'un dispositif d'équilibrage selon l'invention,

la figure 4 est une vue de face en coupe partielle du dispositif de la figure précédente,

la figure 5 est une vue en coupe longitudinale d'une deuxième forme d'exécution d'un dispositif d'équilibrage selon l'invention,

la figure 6 est une vue de face en coupe partielle du dispositif de la figure précédente, et

la figure 7 est une représentation schématique du fonctionnement d'une portion du dispositif des figures 5 et 6,

The description below describes several embodiments of a device according to the invention, being read with reference to the appended drawing comprising the figures where:

FIG. 1 is an elevation view of a portion of a facade cleaning installation,

FIG. 2 is an end view of a portion of the installation of the previous figure,

FIG. 3 is a view in longitudinal section of a first embodiment of a balancing device according to the invention,

FIG. 4 is a front view in partial section of the device of the previous figure,

FIG. 5 is a view in longitudinal section of a second embodiment of a balancing device according to the invention,

FIG. 6 is a front view in partial section of the device of the previous figure, and

FIG. 7 is a schematic representation of the operation of a portion of the device of FIGS. 5 and 6,

In Figures 1 and 2 we have a building 1 with a facade vertical 10 and a roof 11, shown here as being a flat roof. Building 1 is equipped with an installation 2 for cleaning / maintenance of the facade 10 comprising a nacelle 20 suspended by a first pair of cables 21 and a second pair of cables 22 with two beams support 23 and 24 mounted on a frame 25; preferably suitable for move on the roof 11, so that the basket 20 can reach the entire facade 10.

The nacelle 20 shown here comprises in particular two faces ends 20A and 20B each carrying a winch 3 for raising, respectively lower the nacelle 20 along the facade 10. The first winch 3 comprises in particular a first motor 30, preferably a electric motor, a first reducer 31, as well as two drums 32 and 33, mounted coaxially on the wall 20A, while the second winch includes a second motor 34, a second reducer 35 and two other drums 36 and 37, mounted coaxially on the wall 20B. Both drums 32 and 33 of the first winch each receive a cable 210, respectively 211 of the first pair of cables 21 while the two drums 36 and 37 each receive a cable 220, respectively 221 of the second pair of cables 22. The free ends of the cables 210 and 211 of the first pair 21 are fixed, preferably so removable, on beam 23 while the free ends of cables 220 and 221 are fixed in the same way to the beam 24.

A control unit 38 supplies and controls each of the motors 30 and 34.

Optionally and depending on the configuration chosen for the drums, the basket can still include two units complementary, shown schematically in 39, capable of filling one or more of the following functions: passage of cables 210, 211 and 220, 221 distributed along an axis parallel to the axis of rotation of the drums, as shown in Figure 1 in the space between the drums and the units 39, in a configuration where each pair of cables is arranged in a plane perpendicular to the axis mentioned above, as seen on the Figure 2, or then, for another embodiment of the nacelle not represented in the figures, in a plane parallel to said axis, in the portion located between unit 39 and beam 24, slicing of each cable on its drum and safety brake, blocking the cable (s) when a cable break is detected. These different means are known in the art and are therefore not described in more detail here.

Uneven winding of one or more of the above cables on one or more of the drums mentioned may lead to a imbalance in load distribution between cables 210 and 211 or 220 and 221 or an imbalance in platform 20 corresponding to a angular offset around the longitudinal roll axis R or at a angular offset around the transverse pitch axis T, or a combination of these two offsets.

For the embodiment shown, in the case of an offset around the T axis, this offset can be compensated by acting on the relative speeds of the two motors 30 and 34, either by means automatic detection of said offset, either manually by through the control unit 38.

Since the two drums 32 and 33 of the first winch or 36 and 37 of the second winch are controlled by a single motor 30, respectively 34, it is not possible to compensate for a shift around of the R axis by the means which have just been mentioned.

To this end, it is proposed according to the invention to install a device mechanical balancing between the two drums 32 and 33, respectively 36 and 37 of each winch.

According to a first embodiment, the balancing device consists of a three-axis mechanical differential gearbox, as for example the planetary gear train 4, as shown on the Figures 3 and 4. The device 4 comprises an input shaft 40, actuated directly by the motor 30 or 34 or by the reducer 31 or 35, depending on needs. A solar wheel 41 is fixedly mounted on the shaft 40. One or more planetary wheels 42 mesh on the one hand with the sun wheel 41 and on the other hand on an outer ring 43 with teeth interior. The crown 43 carries the drum 32 or 36 suitable for a lifting system. Each of the planetary wheels 42 is mounted with pivotally on an axis 420, said axes being fixed to a flange 44 in free pivoting around the end of the shaft 40. The flange 44 carries the drum 33 or 37.

Considering Figure 4, assuming that the tree 40, respectively the solar wheel 41 turns clockwise, in blocking the drum 32 or 36, respectively the crown 43, we see that the flange 44, carrying the drum 33 or 37 also turns in the direction schedule. If on the contrary the drum 33 or 37 is blocked, respectively the flange 44, we see that the drum 32 or 36 turns in the direction counterclockwise when the shaft 40 rotates clockwise. So, so that there is a simultaneous movement of ascent or descent of the nacelle, depending on the direction of rotation of the shaft, it is necessary that both cables of a pair are wound in opposite directions on both drums, as shown in Figure 4.

The tensile load balancing device 4 operates from the following way, in the case where the two cables of a pair exercise the same tensile force on the two drums, respectively as identical couples are exerted, the two drums are put in rotation, in opposite directions, with the rotation of the shaft 40, therefore raising or lowering the nacelle according to the direction of rotation of the shaft 40. In the case where one of the cables is wound according to a diameter different from the other, making the effort exerted on a cable more important that the force exerted on the other cable, the drum on which is the most taut cable is blocked, causing movement performed by the other drum continues until the difference effort is caught and that the efforts exerted on the two cables are again substantially identical.

So there is a differential balancing device between the two drums so that when one of the cables is stretched more tightly than the other, the torque created by this cable stretched over the drum means that the crown or flange adjoining this drum becomes a fixed point of the device, then allowing the other element, flange or crown, as well to the adjoining drum, to make up for this difference in tension, that the drive shaft is either trained or not. By this device, the two cables of a pair of cables are therefore always subjected to an effort of substantially identical traction, even if the rotational speeds of the two drums are not identical.

Various variants of construction of this device relative to the one just described can be considered. For example the dimensional relationships between the different toothed wheels present may be different from what is described or depicted, as well as known construction variations of type three-axis reducers planetary, for example number of planetary gears different from what has been shown here or other mode of engagement of the gears.

A second embodiment of a balancing device according to the invention is shown in Figures 5 and 6. This device, which is also a three-axis mechanical differential gearbox, corresponds essentially a trochoidal (cycloidal) reducer known as "Cyclo" (registered trademark), including a particular form of execution is described in EP-0.291.052.

This device 5 comprises an input shaft 50, coming as the shaft 40 of the previous device directly from the drive motor or an intermediate reducer. The shaft 50 includes a bearing eccentric cylindrical 51 fixed on the shaft. Eccentric reach results in eccentric rotation a toothed wheel 52 carrying a central bore cylindrical 520, or suitable means of rotation, mounted on the eccentric bearing 51, an external toothing 521, including a shape particular execution will be described more precisely below, thus that a plurality of circular bores 522 regularly spaced on a diameter coaxial with the central bore 520 and the toothing 521. The device 5 further comprises an outer ring 53 with inner teeth 530, a particular embodiment of which will also be described below, partially meshing with the toothing 521 of the wheel 52. A flange 54 is mounted to pivot freely on the shaft 50, carrying a plurality protruding rods 540, each corresponding to a bore 522 of the wheel 52. It can be seen in the figure that the bores 522 have a larger diameter larger than that of the stems 540; actually this bores / rods device is responsible for transmitting the eccentric rotary motion of the wheel 52 in a rotational movement centered on the shaft 50 of the flange 54. For this, the diameter of a bore 522 equals the diameter of a rod 540 plus the offset value of wheel 52. You can have one or more clearances bore / rod for the transmission of this movement, being also possible that one or more bores are arranged on the flange 54 then that the corresponding rod (s) are fixed on the wheel 52. The outer crown carries the drum 32 or 36, carrying respectively the cable 210 or 220 while the flange 54 carries the drum 33 or 37 carrying respectively the cable 211 or 221.

Figure 7 shows a preferred embodiment of a portion of the device which has just been described, showing the meshing of the wheel 52 on the crown 53. The crown 53 carries a plurality of semi-cylindrical housing 531, each carrying a roller 532 in free rotation in said housing 531. In the example shown, the crown 53 includes twenty housings 531 and as many rollers 532. The eccentric wheel 52 carries on its periphery a plurality of housings semi-cylindrical 523, the number of said cylindrical housings being here one unit lower than the number of rollers 532. We therefore understands that, if the crown 53 is blocked, there is a turn of the eccentric wheel 52 for nineteen turns of the shaft 50, respectively one turn of the flange 54 or of the drum 33 or 37 which it carries, for one turn of the shaft 50. By cons by blocking the flange 54 or the drum 33 or 37, respectively the wheel 52, there are twenty turns of the crown 53, respectively of the drum 32 or 36 which it carries for a revolution of the shaft 50.

An advantage of a differential trochoidal balancing device according to this second described embodiment, relative to that planetary according to the first embodiment described, is that the ratio of drum speeds relative to shaft speed much larger, making it possible with a trochoidal balancing device according to this second form of execution, to refrain from placing a speed reducer 31 or 35 between the motor and the input shaft 50 of the balancing device.

Various construction variants of a balancing device trochoidal differential can be considered; for example we can have a difference between the number of rollers 532 and the number of housings 523 on the wheel 52 larger than a unit, for example two or three units. Likewise, the external toothing 521 of the wheel 52 and the internal toothing 530 of the crown 53 may be different from what has been described here, we can have teeth 521 and 530 conventional, one or more teeth being simultaneously engaged. The trochoidal differential balancing device can still be constructed like that described in document EP-0.291.052, comprising several wheels 52 in parallel, eccentrically offset, so as to distribute the forces more smoothly and evenly.

Other types of reducers can also be provided for function as a balancing device. For example a reducer of registered trademark Harmonic Drive or more generally a reducer differential mechanics as found on a car, could very well fulfill the desired function of balancing the tensile forces. Generally speaking, any differential mechanical reducer mounted between the two drums could be used as a medium balancing. Preferably, a three-axis reducer will be used to reasons of compactness of the device.

A balancing device, according to one or other of the forms of execution envisaged, can be supplemented with a decoupling means, for example a ratchet means, allowing for example to easily unwind the cables from their drums when the nacelle is earth, in order to hang them on the suspension beams.

A balancing device, according to one or other of the forms can also be used on a winch fitted with two grip pulleys rather than two drums; preferably adhesion pulleys will then be provided with known means allowing to adhere the cable to a portion of the periphery of the pulley.

The nacelle described above and shown in the figures is designed with the four cables each attached to a corner of the nacelle, other cable fixing configurations can also be envisaged, for example the four cables aligned in a plane containing the longitudinal axis of the nacelle.

The nacelle has also been described so that the winches 3 are there. board; we might as well have a facility where both winches 3 are arranged outside the nacelle, for example on the structure 25 carrying the beams 23 and 24 or directly on these beams. In this form of execution we could even have a single winch, operated by a single motor, the motor axis supporting two sets of drums, each drum set comprising a balancing device according to one or the other of the embodiments described. So, very generally, a single winch, respectively a single drive shaft, may comprise several pairs of drums and / or grip wheels, each pair with its own balancing device.

The balancing device, according to one or other of the forms of execution described, as well as the winch carrying such a device balancing have been described and shown for use with a maintenance nacelle for a building facade; but, both the device balancing that the winch can be used in many others applications.

Claims (20)

1. A winch (3) provided with a device for balancing the traction forces exerted by two cables (210, 211; 220, 221) on two winding means (32, 33; 36, 37) driven in rotation by a common motorised means (30; 34), comprising a three-shaft mechanical differential gearbox (4; 5), the said motorised means (30; 34) driving a first of the said shafts (40; 50), the said winding means (32, 33; 36, 37) each corresponding to one of the said other two shafts,
   characterised in that
   the said differential gearbox is able to put the two drive means (32, 33; 36, 37) in rotation simultaneously, during the functioning of the motorised means.
2. A winch according to Claim 1, characterised in that it is arranged so that the two winding means (32, 33; 36, 37) turn in opposite directions to each other for a common movement of winding or unwinding of the two cables (210, 211; 220, 221).
3. A winch according to one of the preceding claims, characterised in that the mechanical differential gearbox is a planetary gearbox (4).
4. A winch according to one of Claims 1 to 2, characterised in that the mechanical differential gearbox is a trochoidal gearbox (5).
5. A winch according to Claim 3, characterised in that it comprises:

   an input shaft (40) carrying a sun wheel (41),

   at least one planetary wheel (42) fixed with respect to rotation to a plate (44) pivoting freely on a shaft coaxial with the said input shaft,

   an external ring (43) with internal teeth,

   the said planetary wheel or wheels (42) meshing firstly on the sun wheel (41) and secondly on the external ring (43),

   the plate (44) carrying one winding means (33, 37) and the external ring carrying the other winding means (32, 36).
6. A winch according to Claim 4, characterised in that it comprises:

   an input shaft (50) provided with at least one eccentric cylindrical surface (51),

   at least one toothed wheel (52) comprising external teeth (521) pivoting freely on the said eccentric cylindrical surface and at least one means (522) of transmitting an eccentric circular force to a centred circular force,

   an external ring (53) with internal teeth (530), meshing on the teeth (520) on the said toothed wheel (52),

   a plate (54) pivoting free on a shaft coaxial with the said input shaft driven in rotation by the said means (522, 540) of transmitting an eccentric circular force to a centred circular force,

   the plate (54) carrying one winding means (33, 37) and the external ring carrying the other winding means (32, 36).
7. A winch according to Claim 6, characterised in that the internal teeth (530) on the external ring consist of a first number of first semi-cylindrical housings (531) each containing a roller (532) in free rotation in the said first housing, the external teeth (520) on the wheel (52) consisting of a second number of second semi-cylindrical housings (523) meshing on the portions of the rollers (522) not contained in the said first housings.
8. A winch according to Claim 7, characterised in that the first number of first housings (531) is greater than the second number of second housings (523).
9. A winch according to Claim 8, characterised in that the difference between the first number of first housings (531) and the second number of second housings (533) is at least one unit.
10. A winch according to one of Claims 6 to 9, characterised in that the said means of transmitting an eccentric circular force to a centred circular force comprises at least one rod (540) parallel to the input shaft (50), cooperating with a circular bore (522) whose inside diameter is at least the outside diameter of the rod added to the eccentricity of the said eccentric cylindrical surface (51).
11. A winch according to Claim 10, characterised in that at least one of the said circular bores (522) is disposed on the toothed wheel (52), at least one of the said rods (540) being fixed to the said plate (54).
12. A winch according to Claim 10, characterised in that at least one of the said circular bores is disposed on the said plate (54), at least one of the said rods being fixed to the toothed wheel (52).
13. A winch according to one of the preceding claims, characterised in that it is supplemented by a gearbox (31; 35) acting on the input shaft (40; 50).
14. A winch according to one of the preceding claims, characterised in that it is supplemented by a guidance unit (39) able to make the cables (210, 211; 220, 221) pass from a first arrangement in which the said cables are separated on an axis parallel to the rotation axis of the winding means (32, 33; 36, 37) to a second position in which the said cables are disposed in a plane perpendicular to the said axis and vice-versa.
15. A winch according to one of Claims 1 to 13, characterised in that it is supplemented by a guidance unit (39) able to make the cables (210, 211; 220, 221) pass from a first arrangement in which the said cables are separated on an axis parallel to the rotation axis of the winding means (32, 33; 36, 37) to a second position in which the said cables are disposed in a plane parallel to the said axis and vice-versa.
16. A winch according to one of the preceding claims, characterised in that it is supplemented by a distribution unit (39) able to distribute each cable (210, 211; 220, 221) evenly on its winding means (32, 33; 36, 37) when the said cable is wound on the said winding means.
17. A winch according to one of the preceding claims, characterised in that it is supplemented by an emergency braking unit (39) able, when the said unit has detected a cable break, to lock the other cable.
18. A winch according to one of the preceding claims, characterised in that it comprises at least one pair of winding means consisting of two drums (32, 33; 36, 37).
19. A winch according to one of the preceding claims, characterised in that it comprises at least one pair of winding means consisting of two friction drive pulleys.
20. A platform (20) for maintaining a façade (10), characterised in that it is equipped with at least one winch according to one of the preceding claims.

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