WINCH FOR HEAVY LOADS

Abstract

 A winch for winding and unwinding a cable or a sheet, comprising a support structure (3), a drum (2) capable of rotating around a rotation axis (X), a transmission shaft (7) adapted to cause the drum (2) to rotate, a motor (5) provided with a driver, a device for varying the transmission ratios between the motor (5) and the drum (2) with at least two transmission ratios, at least one load cell for measuring the load acting on the cable and for continuously transmitting data on the load to a control system during the operation of the winch, so as to control the driver of the motor (5) and to vary the transmission ratios as a function of the load need.

Description

Field of the invention

[0001] The present invention relates to a winch designed for nautical applications and capable of pulling heavy loads.

Background art

[0002] Increasingly large ships capable of sail propulsion are being offered on the yachting market nowadays. The hulls of these vessels already exceed 50 m in length and the sail masts are over 60 m tall. Although they also have engines, sail propulsion may be used for an important part of their use, also for long crossings and to take part in competitive regattas.

[0003] These sailing ships differ from the large vessels which were used before the widespread use of engine-propelled ships for commercial navigation for some very important aspects. An essential difference is that the ancient sailing ships needed the presence of a large crew to govern the sails. In all cases, the operations performed on the sails on such ships were very slow also in relation to the low speed of such ships. Large-size sailing ships with modern devices and contraptions, mainly for use as training ships by navies, were still built during the last century. Sailing ships of this type were however provided with large crews to operate large-sized sail arrangements.

[0004] A new market for larger size sailing yachts with high-surface sail arrangements which can be maneuvered by crews of a few hands and which could also take part in competitive regattas has been developed over recent years. Such requirements call for very high performance from the governing devices of the sailing ship, which have high maneuvering speed and reaction capacity to the heavy loads which are generated on the sails, which were never necessary on the sailing ships of the past. In addition to allowing to raise and control heavy loads, such devices also provide feedback on the vessel safety. With sail arrangements of the size found on large sailing yachts today, the loads which can be generated on some sails require the sheet to withstand loads over 300 kN. These are loads that only powerful mechanical devices can manage.

[0005] Either electric or hydraulic winches are available on the market for applications on engine-propelled ships or boats, but they have limited power and are insufficient for applications on sailing ships which must take part in regattas, during which the loads on the sail sheet may vary from nearly zero to over 300 kN with such sudden variations of the sail trim to require particularly fast sheet rewinding speeds.

[0006] An example of such winches is disclosed in document US3309066A.

[0007] Winches for use in nautical applications which can provide such performance are not available.

Summary of the invention

[0008] It is the main object of the present invention to provide a winch for use in the nautical field, in particular a winch for a large-size sailing yacht, which is capable of providing slow cable or sheet winding speeds in the presence of very heavy loads and very fast winding speeds in the presence of very low loads on the sheet, or with sheet not-tensioned.

[0009] This object, in addition to others which will be more apparent by reading the detailed description of the invention, is achieved by a winch which, according to claim 1, comprises a support structure; a drum capable of rotating around a rotation axis X to wind or unwind the cable; a transmission shaft adapted to cause the drum to rotate; a motor fastened to the support structure; a device for varying the transmission ratios between the motor and the drum with at least two transmission ratios; at least one control device for controlling the tension of the cable adapted to detect the load acting on the cable and to continuously transmit data on the load to a control system during the operation of the winch, so as to control the motor and the variation of the transmission ratios as a function of the load need.

[0010] In a variant, the device for varying the transmission ratios between the motor and the drum has only two transmission ratios.

[0011] A control device for controlling the tension of the cable comprises a load cell, preferably arranged at a first end of the support structure opposite to a second end of the support structure at which the device for varying the transmission ratios is fastened.

[0012] A further control device for controlling the tension of the cable comprises

• a lever provided with drive rollers for guiding the cable up to an insertion position of the cable on the drum, said lever being pivoted on an axle about which it can rotate;
• a detector for detecting the angular position of the lever with respect to a reference plane, adapted to send an angular position signal of the lever to the control system whereby when the cable is subjected to a high load, the lever performs a rotation in a first rotation direction and the control system controls the variation of the transmission ratio to reduce the angular velocity of the drum,
  and, when the cable is subjected to a low load, the lever performs a rotation in a second rotation direction, opposite to the first direction, and the control system controls the variation of the transmission ratio to increase the angular velocity of the drum.

[0013] Said further control device for controlling the tension of the cable further comprises

- first elastic means, placed at the lever rotation axle, adapted to generate a torsional force generating a rotation of the lever in the second rotation direction,

- and second elastic means adapted to generate an elastic return force opposite to said torsional force.

[0014] Said second elastic means comprise a pneumatic cylinder adapted to produce a tension on the lever by means of a rod of a piston of the pneumatic cylinder and a driving belt on the lever, said driving belt being connected at a first end to the rod and at a second end to the lever.

[0015] The combination of features present in the winch of the invention allows the winch to provide high performance, typically high winding speed of the cable, e.g. of the sheet, when it is not-tensioned and unloaded, e.g. during veering maneuvers, and very low speeds when the sail is loaded and the load acting on the cable is very high.

[0016] By virtue of the features of the invention, as claimed, the performance which is needed on such ships during regattas, but obviously also during all the other steps of sailing, are ensured.

[0017] The dependent claims describe preferred embodiments of the invention.

Brief description of the drawings

[0018] Further features and advantages of the present invention will become apparent in light of a detailed description of a preferred, but not exclusive, embodiment of a winch according to the invention shown by way of non-limitative example, with reference to the accompanying drawings, in which:

Fig. 1 is an axonometric view of the winch of the invention as a whole;

Fig. 2 is an enlarged axonometric view of a first detail in Fig. 1;

Fig. 3 is an enlarged axonometric view of a second detail in Fig. 1;

Fig. 4 is an enlarged axonometric view of a third detail in Fig. 1;

Fig. 5 is an enlarged axonometric view of a fourth detail in Fig. 1;

Fig. 6 is a cross section view of the fourth detail in Fig. 5;

Fig. 7 is a cross section view of the winch in Fig. 1;

Fig. 8 is a first side view of some components of the winch in Fig. 1;

Fig. 9 is a second side view of the components in Fig. 8;

Fig. 10 is a partial view of a cross section taken along the plane A-A of the components in Fig. 8.

Detailed description of preferred embodiments of the invention

[0019] In the description of the invention, the main application of which is in the nautical industry, more specific terms in this domain will be used without limiting the possibilities of application of the winch of the invention to the nautical industry only. The winch of the invention, indicated by reference numeral 1 as a whole, comprises a drum 2 fixed in rotation to the lateral sides of a support structure 3 provided with a base 4 adapted to be fixed to the structure of the ship. Drum 2 is capable of rotating around the rotation axis X to wind and unwind the cable or sheet 22.

[0020] An electric motor 5 is used to move drum 2, is driven by a driver (not shown) connected to motor 5 and comprises a brake 6 for keeping the load static (when the machine is stopped). The rotation axis X' of motor 5 is parallel to the axis X of the drum 2 of the winch. A speed changing assembly, some details of which are shown in greater detail in figure 2, is arranged in the zone between the base 4 of the support structure 3 and the electric motor 5.

[0021] Although reference is made to an electric motor in this description, it is apparent to those skilled in art that other types of motors can be used, such as for example a hydraulic motor or the like.

[0022] A first pneumatic clutch 9 is coaxially fixed to the transmission shaft 7, which transmits torque to the epicycloidal reduction gear 44 (Fig. 7) which, having the casing integral with the drum 2 and the outlet shaft 45 locked on a load cell 40, rotates the drum 2.

[0023] A second pneumatic clutch 10 is coaxially fixed to an auxiliary shaft 8 with rotation axis X" parallel to the axis X of drum 2.

[0024] The speed changing assembly transmits motion from the motor 5 to the transmission shaft 7 of the drum in the following manner. By means of the small diameter toothed wheel 11, the motion generated by the electric motor 5 is transmitted to the toothed belt 14, which in turn meshes the larger diameter toothed wheel 12. The toothed wheel 12 is fixed in a permanent manner to the auxiliary shaft 8. A toothed wheel 13, of diameter substantially equal to the toothed wheel 12, is integral with the pneumatic clutch 10 and is fixed onto the auxiliary shaft 8 so as to mesh it or rotate it idling thereon as a function of the position in which the pneumatic clutch 10 is arranged. The toothed wheel 13 meshes with a toothed belt 15, which transmits a rotation motion to the main transmission shaft 7 by meshing on the toothed wheel 17, having smaller diameter than the toothed wheel 13 and integrally fixed to the transmission shaft 7. A further toothed wheel 18, having smaller diameter than the toothed wheel 13, is also integrally fixed onto the auxiliary shaft 8, which toothed wheel meshes a toothed belt 16, which transmits the rotary motion by means of the meshing with a crown gear or toothed wheel 19, to the clutch 9 and transmits this to the transmission shaft 7 when clutch 9 is in the meshing position, while the crown gear 19 rotates idling around the transmission shaft 7 when clutch 9 is not in meshing position. Indeed, the crown gear 19 is integral with the pneumatic clutch 9 and is fixed onto the transmission shaft 7 so as to mesh it or make it rotate idly thereon as a function of the position in which the pneumatic clutch 9 is arranged. The speed changing assembly thus obtained allows the rotation motion to be transmitted from the electric motor 5 to the main transmission shaft 7 with two different speed ratios:

• a first ratio with slow speed and high torque,
• and a second ratio with high speed and low torque.

[0025] The higher rotation speed is transmitted by motor 5 to the transmission shaft 7 by positioning the pneumatic clutch 10 so that the toothed wheel 13 rotates integrally with the auxiliary shaft 8 and thus rotates at the same angular speed as the toothed wheel 12. Thereby, the transmission shaft 7 is rotated at a high angular speed. In such a position, the pneumatic clutch 9 is also placed in released position by the transmission shaft 7, so that by means of belt 16 the crown gear 18 transmits the motion to the crown gear 19, which rotates idly.

[0026] In order to mesh the ratio with reduced speed, the control system of the winch inverts the working positions of the two pneumatic clutches 9 and 10, arranging clutch 10 idly and arranging clutch 9 meshing. In these positions, belt 15 no longer transmits the rotation motion to the toothed wheel 17, being the toothed wheel 13 idle; instead, belt 16 now rotates the crown gear 19, the clutch 9 and the transmission shaft 7, which are now rotationally integral. With these ratios between the meshing toothed wheels 18 and 19, the angular rotation speed of shaft 7 is slow and the transmitted torque is high.

[0027] In the case of applications of the winch for heavy loads, in which the forces acting on the motion transmission of the motor 5 to the transmission shaft 7 are very high, the toothed belts 14, 15 and 16 are made of special carbon-fiber based material, which in marine environment ensures long working life also if subjected to heavy loads.

[0028] In a preferred variant, the winch also comprises two cable tension control devices 22 during the winding and unwinding operations. Such control devices ensure that, both in conditions of maximum load acting on the cable and in extreme winding and unwinding working conditions with low or nearly no load, cable 22 is kept at the right tension by adjusting the winding speed of the cable itself and preventing the accidental slackening of the turns on drum 2, thus causing overlapping of the cable 22.

[0029] A cable tension control device, in the form of a load cell 40 (Fig. 4 and 7) of known type and thus not described in greater detail here, arranged on the outlet shaft 45 of the epicycloidal reduction gear 44 (Fig. 7) is provided for detecting and managing heavy loads which act on cable 22 during operation. This load cell 40 is used to detect the heavy range loads acting on cable 22, e.g. when a large-size sail is entirely unfurled and upwind. The load cell 40 sends the information on the tension acting on cable 22 to the control system of the winch in order to control its winding speed.

[0030] The load cell 40 is preferably placed at a first end of the support structure 3 opposite to a second end of the support structure 3 at which the transmission radio variation device or speed changing assembly is fixed.

[0031] An outlet shaft 45 of an epicycloidal reduction gear 44, arranged inside drum 2 along the rotation axis X and having a casing which is integral with drum 2, is locked on the load cell 40. The transmission shaft 7 transmits the torque to said epicycloidal reduction gear 44, being connected by its end 7' to an inlet shaft of the epicycloidal reduction gear.

[0032] In applications on large-size sailing ships, e.g. with masts over 50 m tall, the wind acting on a sail may generate loads over 300 kN. Regretfully, the load cells capable of detecting loads of this magnitude cannot detect the loads in the low range close to zero load, when the only loads which are detected on the cable are those caused by friction between the various moving components.

[0033] Given the low sensitivity to small loads on the load cells designed for heavy loads, a further control device 50 is provided which compensates for this lack of accuracy at low loads.

[0034] Said cable tension control device 50, suited when working with small loads, comprises lever 20, or oscillating arm, which can rotate around the rotation bearing 21 on an axis 26 on which it is hinged (Fig. 6). The main components of this control device 50 are shown in greater detail in figure 5.

[0035] Keyed onto the rotation axis of the lever 20 there is also provided an angular position detector of lever 20 which sends the information on the tension acting on cable 22 to the winch control system in order to control its winding speed. In other words, when cable 22 is not pulled by a heavy load, lever 20 tends to rotate counterclockwise as shown in fig. 1 or in fig. 5, by being arranged in a position close to the vertical. In such a case, the signal on the angular position of lever 20 sent to the control signal requests the angular speed of drum 2 to be increased in order to wind cable 22 much faster.

[0036] On the other hand, instead, when the cable or sheet 22 is pulled by a heavy load, lever 20 is pushed to perform a clockwise rotation and is arranged in a position close to the horizontal. In this case, the angular position signal which reaches the control system reduces the angular rotation speed of drum 2, because a higher torque is required in the presence of a greater load on cable 22.

[0037] Lever 20 supports some rollers 23, 24, 25 which work as a guide for cable 22 to make it follow the correct path between the position necessary to be inserted in the groves 30 of drum 2 and the direction of application of the work load.

[0038] The cable tension control device 50 comprises (Fig. 5) a pneumatic spring 27 which by means of the spring piston rod 28 produces a tension force by means of the driving belt 29 on lever 20. This elastic return force opposes, in a lowering direction of lever 20, the force of a torsion spring at the axis 26, which produces a force which allows the lever to be raised towards the vertical position.

[0039] This cable tension control device 50 also serves the functions of a load cell capable of detecting the loads in the low range zone which act on the cable.

[0040] With reference to Figure 8-10, two guides 46 are installed on the base 4 on which a carriage 47 runs which, by means of pulley 48, distributes cable 22 along the helical groove 30 when winding and unwinding the cable on drum 2, and ensures a regular unwinding to prevent the cable from overlapping. In practice, cable 22, after passing on the rollers 24, 23 and 25 (Fig. 5), is guided on the pulley 48 of carriage 47. Carriage 47 is translated parallel to the axis X by means of a lead nut 49 which meshes with the threading of the worm screw 60, this worm screw 60 being integral with a small-diameter toothed wheel 51 which, by meshing on a toothed wheel 52 of larger diameter, integral with drum 2, moves carriage 47 by the same pitch as the helical groove 30. An angular position detector 53 is also provided on the worm screw 60 to monitor the position of carriage 47. Two sensors 54 are provided on the ends of the guides 46 to stop carriage 47 on the respective limit stops. This to-and-fro movement of carriage 47 is controlled by the winch control system taking into account all the factors of load, speed, environmental working conditions of the winch and state of the cable.

[0041] An overlap detector device, shown in Fig. 3, is provided, consisting of a rod 42 arranged parallel to axis X and close to the outer surface of drum 2 at a radial distance such as to leave the passage for a single cable in order to ensure an optimal winding of cable 22 on drum 2, with an always appropriate and constant tension, and to prevent the cable from overlapping. Two movement sensors 43 of rod 42 are provided on each end of rod 42. If a disturbance causes an overlapping of the cable on the previous already wound turn during the winding, the greater height which is generated by the overlapping of the two cable sections causes a raising pressure which acts on rod 42, which thus transmits a signal to the sensors 43, which send the corresponding signal to the control system and the necessary measures needed to eliminate the overlapping may be taken.

[0042] The overlap detector device is preferably arranged parallel to the axis X, at one side of the base 4 which is opposite to the side of the base 4 on which the first control device 50 is fixed.

[0043] This overlap detector device further acts as a safety device if the load cell 40 and/or the control device 50 display problems.

[0044] By virtue of these features, the winch of the invention can deal with all operating conditions which arise on a high-performance sailing ship with large sail surfaces and may deal with conditions which arise during a regatta.

Claims

1. A winch, in particular for winding and unwinding a cable, comprising a support structure (3), a drum (2) capable of rotating around a rotation axis (X) to wind or unwind the cable, a transmission shaft (7) apt to cause the drum (2) to rotate, a motor (5) fastened to the support structure (3),
further comprising a device for varying the transmission ratios between the motor (5) and the drum (2) with at least two transmission ratios, at least a control device for controlling the tension of the cable apt to detect the load acting on the cable and to continuously transmit data of the load to a control system during the operation of the winch, so as to control the motor (5) and the variation of the transmission ratios according to the load need.

2. A winch according to claim 1, wherein there is provided a control device for controlling the tension of the cable comprising a load cell (40), arranged preferably at a first end of the support structure (3) opposite to a second end of the support structure (3) at which the device for varying the transmission ratios is fastened.

3. A winch according to claim 2, wherein on said load cell (40) is fitted an outlet shaft (45) of an epicycloidal reduction gear (44), arranged inside the drum (2) along the rotation axis (X) and having a casing which is integral to the drum (2), said transmission shaft (7) being apt to transmit the torque to said epicycloidal reduction gear (44).

4. A winch according to any one of the preceding claims, wherein there is provided a control device (50) for controlling the tension of the cable comprising:

- a lever (20) provided with drive rollers (23, 24, 25) for guiding the cable (22) up to an insertion position of the cable on the drum (2), said lever (20) being pivoted on an axle (26) about which it can rotate;

- a detector for detecting the angular position of the lever (20) with respect to a reference plane, apt to send an angular position signal of the lever to the control system;
whereby when the cable (22) is subjected to a high load, the lever (20) performs a rotation in a first rotation direction and the control system controls the variation of the transmission ratio to reduce the angular velocity of the drum (2),
while, when the cable is subjected to a low load, the lever (20) performs a rotation in a second rotation direction, opposite to the first direction, and the control system controls the variation of the transmission ratio to increase the angular velocity of the drum (2).

5. A winch according to claim 4, wherein said control device (50) for controlling the tension of the cable comprises:

- first elastic means, placed at the axle (26), apt to generate a torsional force generating a rotation of the lever (20) in the second rotation direction,

- and second elastic means apt to generate an elastic return force opposite to said torsional force.

6. A winch according to claim 5, wherein said second elastic means comprise a pneumatic cylinder (27) apt to produce a tension on the lever (20) by means of a rod (28) of a piston of the pneumatic cylinder and a driving belt (29) on the lever (20), said driving belt (29) being connected at a first end to the rod (28) and at a second end to the lever (20).

7. A winch according to any one of claims from 4 to 6, wherein on a base (4) of the support structure (3) there are provided guides (46) for translating a carriage (47) which, provided with a further drive roller (48), is apt to distribute the cable (22) along the helical groove (30) of the drum (2).

8. A winch according to claim 7, wherein the control system is apt to control the translation movement of said carriage (47) parallel to the first rotation axis (X).

9. A winch according to any one of the preceding claims, wherein there is provided a detection device for detecting an overlapping of the cable (22) comprising a rod (42) arranged parallel to the first rotation axis (X) and at a radial distance from the outer surface of the drum (2) such as to allow the passage in radial direction for a single section of the cable.

10. A winch according to claim 9, wherein there are provided movement sensors (43) at each end of the rod (42) for detecting a movement of the rod (42), said movement sensors (43) being apt to send a corresponding signal to the control system.

11. A winch according to any one of the preceding claims, wherein the device for varying the transmission ratio between the motor (5) and the drum (2) provides only two transmission ratios.

Drawing