RU2783014C1 - Device for tensioning a rope coming from a remotely positioned drum - Google Patents

Abstract

FIELD: lifting mechanisms.

SUBSTANCE: invention relates to the field of lifting mechanisms. The device for tensioning the rope descending from the remotely located drum contains the first (40) and second (80) rollers, as well as an electric motor (63). A clutch capable of transmitting torque is included in the kinematic chain between the electric motor and the first roller. The clutch contains a driving (50) and a driven (45) shafts, as well as a spring (70), which has a friction connection with one and contacts its end section with another of these shafts. The end section of the spring (70) in this case is able to perceive the force in that circumferential direction, in which the weakening of the said frictional connection is ensured.

EFFECT: elimination of slippage of the first roller along the rope when the rope is tensioned, which prevents wear of the first roller and the rope.

10 cl, 8 dwg

Description

Technical field

[1] The invention relates to the field of lifting mechanisms, in particular to auxiliary devices for winches, and can be used on helicopters, for example, as an element of rescue equipment.

Prerequisites for the invention

[2] Lifting and towing winches on aircraft and boats typically use a metal cable as the rope. Due to the inherent properties of metal, such a rope has a high elasticity, and in the absence of a restraining force, it takes up a position in the form of an arc of a large radius. When part of the load being lifted is torn off or when the load being lowered meets an obstacle, the rope moves up and tends to unwind on the drum, which can cause rope entanglement and failure of the winch. Modern winches are equipped with rope tension mechanisms that are able to provide the required tightness of the rope on the drum even when the load on the rope is sharply reduced.

[3] However, often the place where the rope comes off the vehicle body is located at some distance from the winch. For example, such a situation occurs when the winch is installed at the front door of the helicopter, and the lifting and lowering of the cargo needs to be carried out through the opening in the rear of the fuselage. In another example, the winch may be centered on the deck of the vessel while the load being lifted or lowered is overboard.

[4] In the cases described, even if the required rope tension is provided near the drum, a possible reduction in load and the resulting loosening of the rope can lead to the fact that the rope begins to accumulate inside the vehicle. As a result of this process, the rope may catch on other equipment and cause damage to it, or may put people on the vehicle at risk. Thus, it seems highly desirable that the rope be taut not only near the drum, i.e. inside the winch, but also throughout that part of the vehicle body through which the rope passes.

[5] From patent publication CN204549914 U, 08/12/2015, a rope tensioning device is known, which is designed to work together with a remotely located winch. The known device contains two rotating rollers that compress the rope passing between them, while the rollers are driven by a torque source. However, this source does not disclose what the ratio of the linear speed of the rollers and the speed of the rope should be, and also by what means it is provided. In the meantime, this information is critical to the operation of the device, given that the speed of the rope is subject to change depending on the number of layers of rope that are on the drum at any given time.

[5][5] Patent publication DE3121733 A1, 01/27/1983 discloses a device for tensioning a rope that can be used in tandem with a winch, and which is the prototype of the invention. Rope tension in the prototype is provided by two rotating rollers in contact with the rope and driven by a torque source. In order to ensure the guaranteed tension of the rope, the speed of the rollers is set so that the linear speed of the rollers when the rope is released is greater than the speed of the rope. Similarly, when cleaning the rope, the rotational speed of the rollers is maintained at a value at which the linear speed of the rollers is less than the speed of the rope. In other words, the tension of the rope in the prototype is provided by the constant slip of the rollers on the rope.

[6] The disadvantages of the prototype are due to the fact that the rope formed by twisting steel wires has an uneven and hard surface, the constant friction of which on the surface of the rollers leads to intense wear of both the rollers and the rope itself. As a result, the strength of the rollers and the rope is gradually reduced, which negatively affects the reliability of the prototype. Thus, the trouble-free operation of the prototype of the invention can only be ensured with a sufficiently frequent replacement of the rollers and the rope.

[7] The technical problem to be solved by the invention consists in a significant extension of the service life of the device for tensioning the rope coming off a remotely located drum, and in essence, in reducing the wear intensity of the elements that provide tension to the rope.

The essence of the invention

[8] To solve this technical problem, as an invention, a device for tensioning a rope descending from a remotely located drum (hereinafter - the Device) is proposed. The device contains the first and second rollers, as well as an electric motor. The first and second rollers are in contact with the rope and are located on both sides of it. When the rope comes off the drum, the electric motor is able to rotate the first roller in the direction in which the direction of the velocity vector of the first roller in the area of its contact with the rope coincides with the direction of the rope movement. A clutch is included in the kinematic chain between the electric motor and the first roller, capable of transmitting a torque limited to such a given value at which the interaction of the first roller with the rope occurs without slipping. The clutch contains a driving and driven shafts, as well as a spring, which has a frictional connection with one and contacts its end section with another of the said shafts. In this case, the end section of the spring is able to perceive the force in that circumferential direction of the spring, in which the weakening of the said frictional connection is ensured.

[9] The technical result of the invention is that the first roller, receiving torque from the electric motor, is able to pull the rope in the direction away from the drum by means of the second roller by rolling along the rope without slipping, which prevents wear of the first roller and the rope.

[10] The causal relationship between the features of the invention and the technical result is as follows. The device is equipped with a clutch, which is a limiting torque clutch. The clutch is located in the kinematic chain between the electric motor and the first roller, while the excess torque transmitted by the electric motor, which could cause the first roller to slip along the rope, is utilized in the specified clutch. The friction surfaces of the elements that make up the coupling and transmit torque through frictional coupling are wear-resistant and capable of a long service life.

[11] In the first particular case of the invention, the first and second rollers are located relative to the rope so that the plane in which the axes of rotation of the first and second rollers lie is perpendicular to the axis of the rope. This version provides fixation of the rope with the help of a minimum number of rollers, which is equal to two. The first and second rollers fix the rope between themselves in order to ensure effective transmission of the pulling force, as well as to prevent uncontrolled movement of the rope towards the drum when the force from the load is weakened.

[12] In the development of the first particular case of the invention, the Device contains an elastic element acting on the first and second rollers in the direction of each other. This design improves both the efficiency of fixing the rope between the first and second rollers, and the efficiency of transferring to the rope the force from the first roller, which acts in the opposite direction to the drum.

[13] In the second particular case of the invention, the drive shaft of the coupling is located inside the driven shaft, while the spring through its inner circumferential surface has a frictional connection with the outer surface of the drive shaft, and through its end section has engagement with the driven shaft. Compared to a configuration in which the clutch driven shaft is located inside the drive shaft, this design allows the driven shaft not to be extended axially outside the drive shaft, which minimizes the axial clearance of the Device.

[14] In the development of the second particular case, the driven shaft is provided with a protrusion that creates a stop for the end section of the spring, while the force from the protrusion acts on the spring in the direction of its unwinding. The implementation of the protrusion on the driven shaft allows for the tangential direction of the force acting from the spring on the driven shaft, which increases the efficiency of torque transmission.

[15] In the third particular case of the invention, said end section of the spring is the first end section, while the second end section of the spring is similar to the first end section. This design makes it possible to provide a stop for the second end section of the spring, which contributes to the unwinding of the spring along its entire length. As a result of this, the smoothness of the clutch operation is increased and a more accurate operation of the friction connection is achieved in terms of maintaining the transmitted torque at a given value.

[16] In a fourth particular case of the invention, when the rope is being pulled onto the drum, the motor is capable of entering a state that allows free rotation of the first roller. This design, when cleaning the rope, ensures the tension of the rope only due to the force that presses the first and second rollers against each other. It should be noted that, in contrast to the rope release mode, when the lack of traction force is compensated by the pulling force from the first roller at a low weight of the load, when the rope is removed, the traction force required to tension the rope is guaranteed to be created by the drum. The function of the first and second rollers in the rope cleaning mode is to counteract the specified traction force, which is provided by the compression of the rope by the first and second rollers. Accordingly, the transfer of additional torque to the first roller in this mode is not necessary.

[17] In the fifth particular case of the invention, the first roller and the driven shaft of the clutch are rigidly connected or integral with each other. In this design, the transmission of torque from the driven shaft of the clutch to the first roller is characterized by maximum efficiency. In addition, this design ensures the compactness of the Device.

[18] In a sixth embodiment of the invention, the second roller is driven by an electric motor. In this version, the rope experiences a pulling force from both the first and second rollers, which increases the efficiency of the rope tension.

[19] In the seventh particular case of the invention, the rope, when passing over the first roller, changes its direction at a right angle. This design allows not only to ensure the tension of the cantata, but also to set the direction of the rope for its controlled descent from the vehicle body in order to lift or lower the load.

Brief description of the drawings

[20] The implementation of the invention will be explained with reference to the figures:

Fig. 1 - a fragment of the fuselage of the helicopter in a section showing the Device and a remotely located drum;

Fig. 2 - kinematic diagram of the Device;

Fig. 3 - general view of the Device from the front-right;

Fig. 4 - front-right view of the Device in section;

Fig. 5 - view of the Device on the left;

Fig. 6 is an A-A sectional view of the Device of FIG. 5, expanded projection;

Fig. 7 - element-by-element image of the limiting torque clutch, front-left view;

Fig. 8 is an element-by-element representation of the torque limit clutch, front-right view.

It should be noted that the shape and dimensions of the individual elements shown in the figures may be conditional and may be shown in such a way as to most clearly illustrate the relative position of the Device elements and their causal relationship with the technical result.

Implementation of the invention

[21] The implementation of the invention will be shown on the best examples of the invention known to the authors, which are not restrictions on the scope of protected rights.

[22] FIG. Figure 1 shows a fragment of the helicopter fuselage, which is a working compartment 1. In front of the working compartment 1, a winch 3 is installed, which is designed to lower and raise cargo while the helicopter is in the air. It should be noted that these operations can be carried out both through the front door (not shown), next to which the winch 3 is installed, and towards which it can be deployed, and through the hatch 2 of the working compartment 1.

[23] The lifting or lowering of cargo through the front door allows it to be transported in the working compartment 1, however, if the weight of the cargo is large enough, then these operations can cause an undesirable roll of the helicopter. In the case of hatch 2, the cargo can be transported without placing it in the working compartment 1, i.e. when the load is suspended, which allows you to lift and transport heavier loads without disturbing the balance of the helicopter. It should be noted that instead of the hatch 2 or in addition to it, the working compartment 1 may contain a wider lower opening that allows lifting cargo into the working compartment 1.

[24] The design of the winch 3 can be any, provided that the winch 3 includes a drum 6, on which the rope 7 is wound. Preferably, the winch 3 is equipped with a rope tension mechanism that ensures tight laying of the rope 7 on the drum 6 in all modes of operation of the winch 3. However, if only the winch 3 is involved in lifting or lowering the load, then the reliable implementation of these operations can only be guaranteed when using the front door, when the rope comes off the drum 6 immediately down.

[25] In contrast, lifting or lowering a load through the hatch 2 using the winch 3 alone becomes difficult. For example, the release of the rope 7 through the hatch 2 for the subsequent lifting of the load may be accompanied by the accumulation of the rope 7 in the working compartment 1, since the small dead weight of the part of the rope 7 released from the helicopter may not be sufficient to overcome the friction force between the rope 7 and the floor 4 of the working compartment 1. Similar the situation can also occur when lowering the load, when the lowered load reaches the ground, and the winch 3 continues to work for the release of the rope 7 for some time. As shown above, the accumulation of the rope 7 in the working compartment 1, in addition to difficulties in using the winch 3 for its intended the risk of damage to other equipment located in the working compartment 1, and also poses a threat to people in the working compartment 1.

[26] In the meantime, a rope tensioning device 10 (hereinafter referred to as device 10) is installed near the hatch 2, which ensures the tension of the rope 7, essentially, throughout the entire section of the working compartment 1 between the winch 3 and the hatch 2, which eliminates the occurrence of the problems described above. .

[27] The device 10 (FIGS. 1-6) comprises a housing 11, which is attached to the fuselage strength elements 5 through its support portions 12. The housing includes the first and second plates 13 and 14, in which the first and second bearings 20 and 30 are respectively fixed with their outer rings. The movable inner rings of the first and second bearings 20 and 30 hold the first and second shaft elements 21 and 31, respectively, using screw pairs 41 are rigidly connected to each other, as well as to the first roller 40 located between them.

[28] The first and second shaft members 21 and 31 have first and second cavities 22 and 32, respectively (FIGS. 7 and 8). In turn, the first roller 40, on the outer circumferential surface of which the first groove 48 is provided for contact with the rope 7, is rigidly connected to the hub 42. In the configuration shown in FIG. 2-8, the first roller 40 and the hub 42 are integrally formed as a single piece. Hub 42 includes first and second hub members 43 and 44 that are positioned within cavities 22 and 32 such that first and second shaft members 21 and 31, together with hub 42, substantially form a single shaft 45 (FIG. 2). At the same time, the single shaft 45 is the driven shaft of the torque limit clutch, the design and purpose of which are detailed below. In the following, the single shaft 45 is referred to as the driven shaft 45.

[29] Inside the driven shaft 45 lies the drive shaft 50, rigidly connected with the carrier 61 of the planetary gearbox 60. In turn, the sun gear 62 of the planetary gearbox 60 is fixed on the same shaft with a torque motor 63, which is a synchronous motor with permanent magnets on the rotor . The electric motor 63 is connected to the on-board electrical network of the helicopter through the control unit 65.

[30] Thus, the electric motor 63 is able to drive the input shaft 50 by transmitting torque through the planetary gear 60. It should be noted that the planetary gear 60 is a reduction gear whose output speed is less than the input speed with a corresponding increase in torque. moment. More specifically, the speed of the planet carrier 61 is less than the speed of the sun gear 62 by about 10 times.

[31] Further, the torque transmitted from the planetary gear 60 to the drive shaft 50 has the direction shown by the arrow 55, i. coinciding with the clockwise direction when looking at the device 10 from the right side, as shown in FIG. 3.

[32] The drive shaft 50 includes a transmission section 51 on which the main spring 70 is placed. spinning or heating. In an effort to twist or shrink, respectively, i.e. return to the unloaded state, the spring with its inner circumferential surface 71 is pressed against the outer surface 52 of the transfer section 51 and forms a frictional connection with it. In the context of this presentation, the frictional connection of a shaft and a spring is understood as such a connection in which a tangentially directed static friction force arises between the shaft and the spring, capable of transmitting torque from one of these elements to another.

[33] At its first end portion 72, the main spring 70 has a first bearing surface 73 located perpendicular to the inner circumferential surface 71. In turn, the first shaft element 21 in its cavity 22 has a first protrusion 23 with a first contact surface 24. Similarly to the first end section 72, the second support surface 75 is made on the second end section 74 of the main spring 70, and the second contact surface 34 is made on the second protrusion 33 located in the cavity 32 of the second shaft element 31.

[34] The transfer section 51 with the main spring 70 mounted thereon is located in the hole of the hub 42, while the first and second projections 23 and 33 are located on the first and second shaft elements 21 and 31 so that the first bearing surface 73 is in contact with the first contact surface 24, and the second bearing surface 75 is in contact with the second contact surface 34. Thus, when the drive shaft 50 rotates under the action of the motor 63, i. in the direction of arrow 55, the main spring 70 abuts with its first bearing surface 73 against the first contact surface 24, whereby the torque is transmitted from the input shaft 50 to the output shaft 45.

[35] However, abutting against the first protrusion 23, the first end portion 72 receives the reaction force of the first protrusion 23, which acts on the first end portion 72 in the circumferential direction of the main spring 70 corresponding to the direction of its unwinding. Since the untwisting of the main spring 70 increases its inner diameter, the frictional connection of the main spring 70 with the transmission section 51 is weakened.

[36] When the reaction force of the first protrusion 23 is increased to a design value that generates a torque greater than the predetermined torque value, the main spring 70 begins to slip its inner surface 71 along the outer surface 52 of the transfer portion 51. Thus, the friction coupling of the main the spring 70 with the transfer section 51 is capable of transmitting a torque limited to a predetermined value, and the assembly of the input shaft 50, the main spring 70 and the driven shaft 45, in essence, is a torque limit clutch.

[37] Note that the second protrusion 33 provides a stop to the second end portion 74, which prevents the second end portion 74 from rotating relative to the transfer portion 51 in the direction opposite to the direction of the arrow 55. As a result, the main spring 70 unwinds along its entire length, contributing to smoother transmission of torque.

[38] Next, the rope 7 is fed onto the first roller 40 from the drum 6 in a substantially horizontal position and exits the first roller 40 towards the hatch 2 in a vertical position, i. the rope 7 moves along the first roller 40 in the direction of the arrow 55. The electric motor 63, which turns on when the rope 7 starts to leave the drum 6 towards the hatch 2, causes the first roller 40 to rotate also in the direction of the arrow 55. In other words, the electric motor 63 drives the first roller 40 into rotation in the direction in which the direction of the velocity vector of the first roller 40 at the site of its contact with the rope 7 coincides with the direction of movement of the rope 7. Rotating in the direction of movement of the rope 7, the first roller 40 creates a force on the rope 7 due to the rolling friction force , directed from the drum 6, i.e. pulling force. It should be noted that when cleaning the rope 7 onto the drum 6, the electric motor 63 is not turned on, as a result of which the drive shaft 50, and with it the first roller 40, rotate freely.

[39] The second roller 80 is located on the other side of the rope 7 with respect to the first roller 40 and is rotatable on a pin 81 that passes through the second roller 80. The pin 81 is attached at its ends to the lower ends 91 of the H-bracket 90. The upper ends 92 brackets 90 are pivotally mounted on a rod 84 fixed on the first and second plates 13 and 14. In the area between its lower and upper ends 91 and 92, the bracket 90 includes a transverse bar 93. Thus, the corresponding rotation of the bracket 90 relative to the axis of the rod 84 leads to a parallel displacement of the pin 81, and with it the second roller 80 towards the first roller 40.

[40] Rod 84 is fitted with two pressing springs 86, which, with their first ends, abut against a support element 89 rigidly connected to the housing 11, and with their second ends against a cross bar 93. The elastic force of the pressing springs 86 through the cross bar 93 acts on the bracket. 90 so that its lower ends 91 tend to turn towards the first roller 40. Accordingly, the second roller 80 is displaced towards the first roller 40, as a result of which the first and second rollers 40 and 80 provide joint coverage and clamping of the rope 7 between their outer circumferential surfaces. . One of ordinary skill in the art will recognize that instead of two pressure springs 86, a single pressure spring or other resilient element capable of performing the function described above can be used.

[41] On the rod 84 on the outer side of the body 11, a handle 95 is fixed, the rotation of which against the action of the pressing springs 86 allows you to move the second roller 80 away from the first roller 40, which is necessary for threading the rope 7 into the device 10.

[42] The first and second gears 47 and 87 (FIGS. 2, 4, 6), which are engaged with each other, are rigidly connected to the first and second rollers 40 and 80, respectively, due to which the torque from the first roller 40 is transmitted to the second roller 80 by reversing its direction. When the rope 7 passes between the first and second rollers 40 and 80, from the side of each of them, the rolling friction force acts on the rope 7, which is directed in the direction opposite to the side of the drum 6. Thus, when the rope 7 is released, each of the first and second rollers 40 and 80 exerts a pulling force on the rope 7, which provides tension to the rope 7.

[43] The outer circumferential surface of the second roller 80 has a second groove 88 similar to the first groove 48 of the first roller 40, whereby the first and second rollers 40 and 80 surround the rope 7 so as to fix the rope 7 in the axial direction and increase the contact area. Thus, the rope 7 is only able to move relative to the first and second rollers 40 and 80 in their tangential direction. The shape and dimensions of the first and second grooves 48 and 88 are calculated so that when the first and second gears 47 and 48 rotate, the first and second rollers 40 and 80 have the same linear speed in their contact areas with the rope 7.

[44] With respect to the first gear 47, note that it is integral with the second shaft member 31 as a single piece.

[45] It should be noted that the transmission of torque to the second roller 80 is not necessary, and a sufficient level of pulling force on the rope 7 can be provided due to the torque from the first roller 40 and the elastic force of the pressing springs 86 acting on the first and second rollers. 40 and 80 towards each other.

[46] Further, the rope 7 is laid on the drum in 6 layers, each of which is a horizontal row of coils, located side by side with each other. The gear ratio of the planetary gearbox 60 is chosen so that, with a hypothetically rigid transmission of torque along the kinematic chain between the electric motor 63 and the first roller 40, the linear speed of the first and second rollers 40 and 80 would be greater than the speed of the rope 7 descending from the topmost layer when fully laid rope 7 on the drum 6. In addition, the release of the rope 7 is accompanied by a decrease in the number of its layers on the drum 6, as a result of which, at a constant speed of the drum 6, with an increase in the length of the released part of the rope 7, its speed relative to the first and second rollers 40 and 80 decreases.

[47] Thus, in the case of a rigid connection between the motor 63 and the first roller 40, this circumstance would cause the first and second rollers 40, 80 to slip along the rope 7 and the resulting undesirable effects that were described above. However, this problem is solved by including a torque limit clutch in the kinematic chain between the motor and the first roller 40, which limits the torque transmitted from the motor 63 side to the first roller 40 side to a predetermined value. Essentially, the set torque value is the limit torque value that can be transmitted through the friction connection between the transmission section 51 and the main spring 70.

[48] Further, the predetermined amount of torque transmitted by the frictional connection between the transmission section 51 and the main spring 70 is set so that the interaction of the first and second rollers 40 and 80 with the rope 7 occurs without slipping. In other words, the first and second rollers 40 and 80 receive a torque that is less than the torque necessary to overcome the static friction force between the rope 7 and the rollers 40 and 80. All excess torque coming from the planetary gear 60 is utilized when the main gear slips. spring 70 along the transfer section 51. It should be noted that in the context of this presentation, an assumption is made in which the friction force that prevents the rope from slipping along the roller rolling on it is equated to the static friction force between the rope and the stationary roller.

[49] Thus, in order to equalize the speed of the rope 7 and the linear speed of the first and second rollers 40 and 80, the mainspring 70 continuously slides over the transfer section 51 during the entire time of the rope 7 extension. However, this does not lead to noticeable wear of the mainspring 70 or transfer section 51, since these elements are made of hard wear-resistant steel, and their surfaces are treated to a minimum coefficient of friction. The predetermined amount of torque transmitted by the friction connection between the transfer section 51 and the main spring 70 is provided by a properly selected elastic force of the main spring 70, which arises, for example, as a result of the preliminary unwinding of the main spring 70 before it is installed on the transfer section 51. These factors ensure a trouble-free operation of the limiting torque clutch during the entire service life of the device 10.

[50] Device 10 operates as follows.

The control unit 65 starts the electric motor 63 at the moment the drum 6 begins to rotate to release the rope 7, which eliminates the sagging of the rope 7, even if there is no load on it. The planetary gearbox 60 transmits torque from the electric motor 63 to the torque limit clutch, which includes the drive shaft 50, the main spring 70 and the driven shaft 45. The drive shaft 50 then rotates in the direction indicated by the arrow 55, and its transmission section 51 through the above-described the main spring 70 carries the frictional connection with it. Through its first end section 72, the main spring 70 transmits torque to the driven shaft 45 connected to the first roller 40.

[51] However, the torque limit clutch transmits to the first roller 40 only that part of the torque from the planetary gear 60, in which the interaction of the first and second rollers 40 and 80 with the rope 7 occurs without slipping. Excess torque is utilized in the torque limit clutch when the main spring 70 slips along the transmission section 51.

[52] As a result, when the rope 7 leaves the drum 6, the first and second rollers 40 and 80 essentially roll over the rope 7, creating a pulling force on it due to the rolling friction force between the rollers 40, 80 and the rope 7. Due to the guaranteed absence of mutual slippage, the first and second rollers 40 and 80, as well as the rope 7, are not subject to wear for a long time.

[53] When the drum 6 rotates to clean the rope 7, the control unit 65 turns off the electric motor 63, which allows the drive shaft 50, and with it the rollers 40, 80, to rotate freely. In this mode, the pulling force required to tension the rope 7 is created by the drum 6, and the counteracting force is provided by the first and second rollers 40 and 80 due to the rolling friction force resulting from the compression of the rope 7 by them. In addition, when cleaning the rope 7, the device 10 performs a lightweight (i.e. by rolling) introduction of the rope 7 into the working compartment 1 and prevents a sharp throw of the rope 7 into the working compartment 1 in the event of an emergency situation associated with the detachment of the load.

[54] In the above-described configuration of the device 10, the drive shaft 50 is located inside the driven shaft 45, while the main spring 70 through its inner circumferential surface 71 has a frictional connection with the outer surface 52 of the drive shaft 50. However, this is not necessary, for example, the driven shaft can be located inside the drive shaft, and the frictional connection of the spring with the drive shaft can be provided through the outer circumferential surface of the spring and the inner surface of the drive shaft.

[55] In the configuration described above, the axis of rotation of the first roller 40 coincides with the axis of the drive shaft 50, and the axis of rotation of the second roller 80 coincides with the axis of the pin 81. As such, in the area of its simultaneous contact with the first and second rollers 40 and 80, the rope 7 passes perpendicular to the plane in which the axes of the first and second rollers 40 and 80 lie. However, this is not mandatory, in order to fix the rope 7, a scheme of many rollers known to a person skilled in the art can be used, which ensures the fixation of the rope by repeatedly changing the direction of its movement and increase the area of its contact with the rollers. At least part of this set may be rollers driven by an electric motor.

Claims (14)

1. A device for tensioning a rope descending from a remotely located drum, containing first and second rollers in contact with the rope and located on both sides of it, and an electric motor that, when the rope leaves the drum, is capable of driving the first roller into rotation in the direction in which the direction of the velocity vector of the first roller at the site of its contact with the rope coincides with the direction of the rope movement, while a clutch is included in the kinematic chain between the electric motor and the first roller, capable of transmitting a torque limited to such a given value at which the interaction of the first roller with the rope occurs without slipping, and the clutch contains a driving and a driven shaft, as well as a spring, which has a friction connection with one and contacts its end section with another of the specified shafts, while the end section of the spring is able to perceive the force in that circumferential direction in which the said friction connection is weakened. 2. The device according to claim. 1, in which the first and second rollers are located relative to the rope so that the plane in which the axes of rotation of the first and second rollers lie is perpendicular to the axis of the rope. 3. The device according to claim. 2, which contains an elastic element acting on the first and second rollers in the direction of each other. 4. The device according to claim 1, in which the drive shaft of the coupling is located inside the driven shaft, while the spring through its inner circumferential surface has a frictional connection with the outer surface of the drive shaft and through its end section has engagement with the driven shaft. 5. The device according to claim 4, in which the driven shaft is provided with a protrusion that creates a stop for the end section of the spring, while the force from the side of the protrusion acts on the spring in the direction of its unwinding. 6. The device according to claim. 1 or 5, in which the said end section of the spring is the first end section, while the second end section of the spring is made similar to the first end section. 7. The apparatus of claim. 1, in which when cleaning the rope on the drum, the motor is capable of being transferred to a state that allows free rotation of the first roller. 8. The device according to claim. 1, in which the first roller and the driven shaft of the clutch are rigidly connected or integral with each other. 9. Apparatus according to claim 1, wherein the second roller is driven by an electric motor. 10. The device according to claim. 1, in which the rope, when passing over the first roller, changes direction at a right angle.

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