Winch for providing a part of unwound cable with a predetermined length

Abstract

A winch comprises a cable roll; a cable having one end fixed to the cable roll and another end configured to electrically connect an electric device to the cable, wherein the cable is further configured to provide the electric device with electric power and/or with data; a framework to which the cable roll is mounted; measuring means connected to the framework and configured to provide data related to the length of an unwound part of the cable; and processing means configured to control winding and unwinding of the cable based on data provided by the measuring means. The cable has a predetermined reference state at which a predetermined fixed reference point is at a reference position in relation to a coordinate system, wherein the length of unwound cable is defined as the distance measured along the cable, between the location of the predetermined fixed reference point and the reference position.

Claims

1. A winch comprising: a cable roll configured to wind and unwind a cable; a cable having one end that is fixed to the cable roll, and another end that is configured to electrically connect an electric device to the cable, wherein the cable is further configured to provide the electric device with instruction data; a framework to which the cable roll is mounted; measuring means connected to the framework and configured to provide data related to the length of an unwound part of the cable; and processing means configured to control winding and unwinding of the cable based on the data provided by the measuring means, the processing means comprising a microprocessor and a storage with movement control software that enables the microprocessor to control movement of the cable roll, wherein the microprocessor is mounted within the framework; wherein there is a predetermined fixed reference point on the cable, and there is a predetermined reference state of the cable, at which the predetermined fixed reference point is at a reference position in relation to a coordinate system, and wherein the length of unwound cable is defined as the distance measured along the cable, between the location of the predetermined fixed reference point and the reference position wherein the electric device is a light emitting device, and the storage comprises light control software that enables the processing means to control the light-emitting device by issuing and forwarding the instruction data to the light emitting device via the cable.

2. The winch according to claim 1 wherein the cable is a reinforced signal cable.

3. The winch according to claim 1 further comprising an electric motor, which is configured to set the cable roll into rotation, and wherein the processing means is configured to control the electric motor.

4. The winch according to claim 1 wherein the measuring means is configured to provide data related to the length of the unwound part of the cable based on the amount of cable which is wound around the cable roll.

5. The winch according to claim 1 wherein the measuring means comprise an encoder which is configured to provide data related to an angle by which the cable roll has rotated, with respect to the position of the cable roll corresponding to the reference state of the cable, and/or an angle which indicates the position of the cable roll.

6. The winch according to claim 1 wherein the processing means is configured to control the angular velocity of the cable roll, by taking into account data related to the length of the unwound part of the cable, and causing the predetermined fixed reference point on the cable to move with a predetermined linear velocity and/or acceleration.

7. The winch according to claim 1 wherein the winch further comprises a magnet which is attached to the cable and a magnet sensor which is configured to sense the magnetic field of the magnet.

8. The winch according to claim 7 wherein the processing means are configured to provide an auto setup function performable to bring the cable into the reference state.

9. The winch according to claim 1 further comprising an electric device which is pinned on the cable.

10. The winch according to claim 1 further comprising an interface configured to receive electric power and/or data from an external controller.

11. The winch according to claim 1 wherein the electric device comprising an interactivity sensor is electrically connected to the cable, and wherein the interactivity sensor is configured to forward data to the cable.

12. A system, comprising: a plurality of winches according to claim 1; and a system controller configured to issue instructions to be executed by a winch to at least one of the plurality of winches, and/or to provide data and/or electric power to at least one electric device that is electrically connectable to the cable of a winch from the plurality of winches.

13. The system according to claim 12 further comprising data connection means, wherein the system controller is configured to use the data connection means to select at least one of the plurality of winches for communication, and to issue instructions to the at least one selected winch.

14. The system according to claim 12 further comprising an electric device that is electrically connected to the cables of at least two of the plurality of winches, wherein each of the at least two winches comprises a motor for driving the respective cable roll.

15. The winch according to claim 9 wherein the electric device comprises a light emitting device, a sound emitting device, a sensor, an actuator, or a motor.

16. The winch according to claim 11 wherein the data comprise instructions.

17. The winch according to claim 1 wherein the framework has an opening through which the cable may exit the framework, and wherein the reference position is located in the opening.

18. The winch according to claim 1 wherein the measuring means comprises a length tracking means that engages an outer circumference of the cable roll.

19. The winch according to claim 1 wherein the cable is further configured to provide the electric device with electric power.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further aspects of the invention will be described below with reference to the attached figures

(2) FIG. 1 illustrates an example of a winch according to the present invention.

(3) FIG. 2 illustrates an example of a system according to the invention where a system controller is used to control a plurality of winches.

(4) FIG. 3 illustrates an arrangement of components in an exemplary embodiment of a winch according to the invention.

(5) FIG. 4 illustrates an exemplary embodiment of a cable roll and a slip ring in a winch according to the invention.

(6) FIG. 5 illustrates, for a particular embodiment, electronic components connected to a circuit board in a winch according to the invention.

(7) FIG. 6 illustrates a view onto the bottom of an exemplary embodiment of a winch according to the invention.

(8) FIG. 7 illustrates an example of an embodiment of a winch with an electrically connected electric device according to the invention.

(9) FIG. 8 illustrates a particular embodiment of a system of winches according to the invention.

DETAILED DESCRIPTION

(10) Exemplary embodiments of the invention are described in the following. However, the invention is not limited to the described examples.

(11) FIG. 1 illustrates an exemplary embodiment of a winch in accordance with the invention. The winch comprises a framework 190. Attached to the framework 190 is a cable roll 140, where a cable 111 is wound up. The cable 111 comprises a sheathing 110 and at least two wires 120 inside the sheathing 110. The cable carries, at its end hanging down from the winch, a pull relief 115. The pull relief 115 is formed such that an electric device can be pinned on. In this way, the cable can carry the weight of the electric device. The wires 120 inside the sheathing 110 of the cable 111 have a plug 125 at their ends, where the electric device can be electrically connected to the wires. A cable guide roll 105 may be provided to guide unwound cable from the cable roll 140 through an opening 195 in the framework 190 of the winch.

(12) An electric device may be pinned on the pull relief 115. The electric device may also be electrically connected to the plug 125. The plug may be positioned near the pull relief 115 in a distance such that an electric device pinned on the pull relief 115 can be plugged to the plug 125. A magnet 135 is attached to the sheathing 110 of the cable 111. The magnet may be attached to the sheathing near the pull relief 115. The magnet 135 may be attached to the sheathing 110 near the end of the cable 111 which is hanging down from the winch.

(13) A part of the cable 111 is wound around the cable roll 140. In its center, the cable roll has a slip ring 128. The slip ring 128 is used to lead electric current from outside the cable roll 140 into the wires 120 inside the sheathing 110 of the cable. The slip ring is electrically connected to a microprocessor 160. The slip ring may optionally be electrically connected to the interface 180. An external controller, i.e. a controller which is not part of the winch, may be attached to the interface 180. The interface 180 may be configured to forward instructions from an external controller to the slip ring 128. The forwarded instructions may be provided, using the slip ring 128 and the wires 120, to an electric device which may be attached to the plug 125. Alternatively or in addition, the interface is configured to forward instructions from an external controller to the microprocessor 160.

(14) The microprocessor 160 is electrically connected to an electric motor 170. The microprocessor 160 controls the motion of the electric motor. The microprocessor 160 may provide control signals to the electric motor 170, and/or the microprocessor 160 may provide the electric motor 170 with current driving the electric motor. The electric motor 170 is configured to drive the cable roll 140 such that it rotates. The cable roll 140 may be configured to rotate in clockwise and in counterclockwise direction. Dependent on the direction of rotation of the cable roll 140, the cable is wound or unwound. A gear may be used to adapt the rotational speed of the electric motor 170 to a desired rotational speed of the cable roll 140. Alternatively or in addition, a gear may be used to change the rotation of the cable roll 140 from one direction to the reversed direction.

(15) In particular embodiments, the measuring means comprise length tracking means 155 and a magnet sensor 130. The measuring means also comprises a measuring controller 150. The measuring controller 150 may be electrically connected to the microprocessor 160. In particular embodiments, the microprocessor 160 may assume the functionality of the measuring controller 150 besides other tasks. The measuring controller 150 receives data from the length tracking means 155 with respect to the rotational motion which the cable roll 140 performs. The length tracking means 155 may also provide data to the measuring controller 150 about the radius of the coil formed by that part of the cable which is still wound around the cable roll 140.

(16) In an embodiment, the measuring controller 150 is also electrically connected to the magnet sensor 130. The magnet sensor is configured to send a signal to the measuring controller if the magnet 135 attached to the cable is sensed by the magnet sensor 130. The measuring controller is be configured to take the position of the cable roll at the moment when it receives a signal, in particular from the magnet sensor, that the magnet is sensed by the magnet sensor, as a predetermined starting position of the cable roll.

(17) The measuring controller 150 is configured to forward data to the microprocessor 160 specifying whether the magnet 135 is sensed by the magnet sensor 130. The microprocessor 160 may be configured to stop the electric motor 170, for example, by sending a corresponding control instruction to the electric motor 170, if the microprocessor 160 receives data from the measuring controller 150 specifying that the magnet is sensed by the magnetic sensor 130. In this way, the winch can be stopped from winding too much of the cable 111 onto the cable roll 140, and/or to touch the framework 190 with an electric device attached to the pull relief 115.

(18) In a particular embodiment, the length tracking means 155 comprise a rotary encoder which issues signals indicating an angle and/or the amount of rotations by which the cable roll 140 has rotated. The signals are issued to the measuring controller 150. The angle may be measured with respect to the above-mentioned predetermined starting position of the cable roll. In particular, the rotary encoder may issue a signal each time when the cable roll is rotated, starting from the predetermined starting position, by a multiple of a fixed angle. The fixed angle may be 7 degrees.

(19) In an embodiment, the length tracking means comprise a potentiometer. The potentiometer is configured to provide a value, in particular, a resistance value, which indicates an absolute position of the cable roll, to the measuring controller 150. The absolute position may be measured with respect to the above-mentioned predetermined starting position. In this way, the measuring controller 150 can determine the absolute position of the cable roll 140 without winding the cable roll to the predetermined starting position.

(20) Based on the data provided by the length tracking means 155, the measuring controller 150 is configured to keep track of the length of that part of the cable 111 which is wound around the cable roll 140. In particular, the measuring controller may be configured to keep track of the number of rotations which the cable roll has been performed beginning with a predetermined starting position. The measuring controller 150 is configured to provide data to the microprocessor 150. In particular, the measuring controller 150 may provide data to the microprocessor 160 referring to the rotational motion of the cable roll and/or referring to the amount of wound and/or unwound cable.

(21) The measuring controller 150 may also be configured to provide data to the microprocessor 160 specifying at least one of: the length of the part of the cable which has been wound or unwound from the cable roll, the rotational speed of the cable roll, the radius of the coil formed by that part of the cable which is still wound around the cable roll 140.

(22) The interface 180 of an embodiment of the winch is configured to permit forwarding digital and/or analog data. Data can be forwarded from the interface 180 into the winch and can be forwarded from the winch to its outside, for example, to an external controller. Data can be forwarded into the winch from the interface 180 to the microprocessor 160 and to the slip ring 128. The interface 180 may be configured to have an address. The interface 180 may be configured to accept data according to the DMX protocol. The interface 180 may be configured to select, from all the data forwarded to the interface from outside the winch, those data which correspond to the address of the interface.

(23) A predetermined fixed reference point 117 is defined on the cable. In a particular embodiment, the predetermined fixed reference point is located at the position where the magnet 135 is attached to the cable 111. The predetermined reference state of the cable is defined by the spatial arrangement of the cable 111 when the cable is wound around the cable roll 140 such that the predetermined fixed reference point 117 is located at a reference position 118. The position of the predetermined fixed reference point is specified in the same coordinate system as the reference position 118. In particular, the reference position may be in the center of an opening 195 in the framework 190. The length L of unwound cable is given by the length of cable between the reference position 118 and the predetermined fixed reference point 117. In a particular embodiment, the origin of the coordinate system used to specify the reference position may be in the axis of the cable roll.

(24) FIG. 2 presents an example of a system for controlling a plurality of winches according to the invention by means of a system controller 210. The winches 220, 230 and 240 are connected to the system controller 210 by a network 250. The network 250 may be a wired and/or wireless network, and the network members may be connected by means of electric cables and/or glass fiber cables. In one embodiment, the winches 220, 230 and 240 are connected to the system controller 210 by a bus system. The network may have, in particular, a bus topology or a star-like topology or a ring topology. In a system with bus-type network, the winches and the system controller may be daisy-chained. For at least a part of the winches, there may be a dedicated connection between the system controller 210 and a particular winch.

(25) In the presented embodiment, a network cable 250 connecting the system controller and the winches 220, 230 and 240 is attached to the interfaces 225, 235 and 245 of the winches. In the presented embodiment, each of the winches 220, 230 and 240 has a respective light emitting device 222, 232 and 242 electrically connected to its cable. A light emitting device may be attached to a pull relief connected to the cable of the respective winch. The cable of each of the winches comprises a sheathing which is wrapped around wires in the inside of the sheathing. The light emitting devices are provided with electricity using the wires inside the sheathing of the cable where a light emitting device is electrically connected to. Each light emitting device is electrically connected to the wires inside the sheathing of a cable by means of a plug attached to the wires. The system controller is configured to issue instructions to each particular winch to control winding or unwinding the cable of the winch. Those instructions may be executed by a microprocessor in the winch. The system controller may also be configured to issue instructions which are directed to the light emitting device electrically connected to a particular winch.

(26) In other embodiments, an electric device which generates an output signal, like a light sensitive device and/or a microphone, may be electrically connected to the cable of at least one of the winches. The output signal from such a device may be transmitted, using the wires in the sheathing of the cable and in the interface of the winch, to the system controller. The system controller may be configured to issue instructions to a winch or to issue instructions to an electric device, in particular, to a light emitting device, electrically connected to the cable of a winch, in response to the output signal of an electric device electrically connected to the cable of a winch. In particular embodiments, the electric device which generates an output signal is a microphone.

(27) In some embodiments, the system controller 210 has stored, for at least one of the plurality of winches 220, 230, 240 which it is enabled to communicate to, a length value specifying a length of cable which has to be unwound by the at least one of the plurality of winches. By having stored length values for each of a plurality of winches, the controller may send instructions to the winches such that the devices, for example, light emitting devices, electrically connected to the winches, form a spatial pattern. In particular embodiments, the length values may be based on function values of a function of one or two variables.

(28) Alternatively or in addition, the system controller may issue instructions to the electric devices electrically connected to the winches. In particular, the system controller may cause electric devices which are light emitting devices to change the brightness of the emitted light. The light emitting devices may comprise light sources with different colors. The system controller may cause the light source to change its color and/or to change its brightness. The external controller may coordinate changes in a light source electrically connected to the cable of a winch with the motion of the winch. By issuing corresponding instructions to a winch as well as instructions to the device electrically connected to the cable of the winch, the system controller may adjust electric devices electrically connected to the cables of a plurality of the winches individually in height. Hence, the external controller may be prepared to provide a spatial pattern of light sources changing their position as well as the emitted light in a coordinated way.

(29) Each winch may be fastened to a ceiling at a predetermined fastening location. The winches may be fastened to a truss system. The truss system may be incorporated into an interior which can be used for installing works of art and/or is intended to comprise some kind of eye-catcher. In particular, such interior may be a trade fair booth ceiling, a show window, a hall in a museum, an environment of a stage, a building at an airport, an atrium of a building or a staircase.

(30) For each winch, a required length value of unwound cable may be derived, by the system controller, from the value of a function having the predetermined fastening location of the winch at the ceiling as input. The system controller may issue one or more instructions to a winch specifying the length of unwound cable to be provided by the winch. By issuing at least one instruction to each of the winches specifying a length of unwound cable based on the length value derived for that winch, the system controller may control the winches such that the electric devices electrically connected to the cables of the winches form a spatial pattern which corresponds to a graph of the function. The length value specified by the system controller 210 in the instructions addressed to a particular winch may vary with time.

(31) In other embodiments, there is at least one electrical device which is connected to more than one of the plurality of winches 220, 230, 240. In particular cases, there is a plurality of attachment points on an electrical device, each of which is pinned on the cable of one of a plurality of winches. Each of the attachment points may be electrically connected to the electrical device. On at least one of the attachment points, the electrical device may be plugged to wires inside the sheathing of the cable of one of the plurality of winches to be electrically connected. The electrical device may be provided with electric power and/or with digital data, such as instructions, by means of the wires inside the sheathing of the cable of at least one of the winches. Instructions to the electric device may be provided from the processing means, in particular, from a microprocessor comprised in at least one of the winches whose cable is pinned on one of the attachment points. Alternatively or in addition, instructions to the electrical device may be provided from the system controller.

(32) The instructions issued by the system controller 210 to the plurality of winches may cause the winches which the electrical device is electrically connected to and/or pinned to wind or unwind their cables. In this way, the attachment points of the electrical device electrically connected to the cables of more than one winch are moved in a coordinated way. In this way, the system controller may cause the electrical device, for example, a large and/or heavy one, to be moved up and down by more than one plurality of winches simultaneously. The motion of the winches may be controlled by the system controller such that an electrical device is tilted and/or inclined and/or turned in a particular way by causing the winches winding or unwinding their cables with different speed. If several electrical devices are electrically connected and/or pinned to more than one winch and are moved in this way, a moving pattern may be created by making the devices move in a similar or identical way. A similar or identical motion of one of the devices may be deferred with respect to the motion of another one of the devices so as to simulate a spatial progress of the motion of a device. A winch may wind/unwind its cable with a linear speed which does not depend on the length of the cable which is wound or unwound. Hence, the motion of a device may not depend on the distance between an electrical device and the ceiling or the ground.

(33) In particular, the electrical devices may be fluorescent tubes. The fluorescent tubes may be linear tubes. A fluorescent tube may be attached, in particular, electrically connected and/or pinned at each of its ends to a different winch of a plurality of winches. A fluorescent tube may have, in particular, a color of red, green or blue. The external controller may be configured to issue instructions to a winch where one end of a fluorescent tube is attached so as to shorten the unwound part of the cable, and may be configured to issue instructions to a winch where the other end of the fluorescent tube is attached to so as to lengthen the part of unwound cable. Alternatively, the system controller can issue instructions to winches where a fluorescent tube is attached so as to lengthen their cable or to shorten their cable. Shortening or lengthening of the cables may be carried out with different velocities and/or accelerations of the cable or of the cable roll. In this way, the system controller may be prepared to cause a rocking motion of the fluorescent tube. The rocking motion may be combined with an up or down movement of the fluorescent tube.

(34) In yet another embodiment of a system according to the invention, a plurality of winches is attached to a floor. The winches may be attached to the floor in a rectangular pattern. At each of the winches, a container comprising an illumination is attached to the cable of the winch. The container may be filled with a gas which is lighter than the air surrounding the container. For example, the container may be a balloon. The balloon may be filled with helium, or the balloon may be filled with heated air. By winding or unwinding the cable of the winch which the balloon is attached to, the balloon can be moved up or down.

(35) In an embodiment, the system controller may be prepared to control the motion of each of the plurality of winches, and may create a spatial pattern formed by balloons, each balloon attached to a winch, each balloon comprising a light source, the balloons floating in the air. The system controller may coordinate the motion of the balloons in the air with changes of the light emitted by a light source in each balloon. A particular kind of motion may be accompanied by a particular kind of light emission. For example, moving the balloon up or down may be accompanied by emitting green light which increases with brightness dependent on the height of the balloon over the floor. The light source in a balloon may be a dimmable LED. The movement of a balloon may be accompanied by sonic events. The sonic events may be sound emissions from at least one loudspeaker arranged in a room where the winches are attached to the floor. The at least one loudspeaker may be located inside at least one balloons.

(36) FIG. 3 illustrates an arrangement of components in an exemplary embodiment of a winch according to the invention. FIGS. 3a and 3b show the winch as seen from two opposite sides.

(37) FIG. 3a illustrates that attached to a framework 310 is an interface which has two separate portions, a power portion 341 which is used to supply electric power to the winch, and a data portion 342 which is used to provide data to the winch. In a particular embodiment, the data portion comprises a plug and a socket as used for a DMX bus. Further mounted on the framework is a circuit board 360 carrying electronic components configured to enable operation of the winch.

(38) In particular, the circuit board 360 comprises at least one microprocessor and has attached conducting wires connecting the circuit board with electric components of the winch. The circuit board 360 further carries dials 364. With the dials 364, an address can be set for the winch which can be used to address the interface of the winch. Data which are intended to be used by the winch or by an electric device electrically connected to the cable 370 of the winch can be sent to the address set with the dials 364. The circuit board 360 also carries dip switches 362. The dip switches 362 may be used to select an operation mode for the winch. In particular, the dip switches 362 may be used to set the winch into an adjustment mode, or into a play mode. In adjustment mode, the winch may be configured to carry out particular actions. In play mode, the winch actually may carry out actions which it has been configured to carry out.

(39) The embodiment further comprises a transformer 350. The transformer 350 is configured to provide power to the circuit board 360 and to an electric motor 320 which is mounted on the opposite side of the framework 310 and which is configured to drive the cable roll 330. A cable 370 with a sheathing having a rectangular cross section with rounded-down corners, which surrounds electric wires, is wound around the cable roll 330. The electric wires leading through the cable 370 are connected to wires from a slip ring 380 whose axis coincides with the axis of the cable roll 330.

(40) On top of the framework 310, a clip 315 is attached to the framework 310. The clip 315 is used to attach the framework 310 of a winch to some kind of truss or other supporting device.

(41) FIG. 3b illustrates the arrangement of components of a winch according to the invention from the side opposed to that shown in FIG. 3a. Mounted on the framework 310 is an electric motor 320 which is configured to drive the cable roll 330 of the winch. Attached to the electric motor 320 is a gear 392 which adapts the rotational velocity of the electric motor 320 to the rotational velocity of the cable roll 330. Further attached to the electric motor 320 is an encoder 390 which is configured to provide data to a circuit on the circuit board 360 indicating a rotational motion of the cable roll 330. Mounted to the framework is a potentiometer 395 which provides information about the position of the cable roll 330 relative to a start position to circuitry on the circuit board 360. The potentiometer 395 is driven using a belt 396 which connects a roll 397 attached to the axis of the potentiometer 395 with a second roll 398 which is driven by the motor 320 by means of gear 392. In an embodiment, the rolls 397, 398 as well as the belt 396 may be toothed so as to avoid slipping of the belt 396.

(42) FIGS. 4a and 4b illustrate an example of an arrangement of the cable roll 330 and a slip ring 380 as included in a particular embodiment of the winch. A cable 370 with a sheathing having a rectangular cross section with smoothed-down corners and which encloses wires is wound around the cable roll 330. On one side of the cable roll 330, centered on the axis of the cable roll, is an axis stub 410. The axis stub 410 is prepared to be inserted into a bearing which is attached to the framework 310 of the winch.

(43) The cable 370 is attached with a screw 421 to the cable roll 430 near one of its end points.

(44) The wires inside the sheathing of the cable 370 are led from an end point of the sheathing into a socket 488 embedded into a side portion 440 of the cable roll 330. The socket 488 is configured to be connected to a plug 487. A plug 487 is attached to the end of the cables 486 which are led out of the movable part 482 of the slip ring. The plug 487 may be sunk in an opening in the side portion 440 of the cable roll 330 when it is connected to the socket 488. In one embodiment, the opening in the side portion 440 of the cable roll is centered on the axis of the cable roll 330.

(45) A connector element 450 is fixed to the movable part 482 of a slip ring 380. The slip ring 380 is prepared to be mounted to the framework 310 of the winch such that the axis of its movable part 482 coincides with the axis of the cable roll 330. The connector element 450 and the movable part 482 of the slip ring 380 are rigidly coupled. A pin 442, which is attached to the side portion 440 of the cable roll 430, extends into an opening of the connector element 450. Hence, if the cable roll 330 rotates, the connector element 450 as well as the movable part 482 of the slip ring 380 rotate together with the cable roll 330. As the axis of the slip ring 380 coincides with that of the cable roll 330, the movable part 482 of the slip ring 380 can follow the rotation of the cable roll 330.

(46) In this way, the wires coming out of the cable roll 330 and leading into the movable part 482 of the slip ring 380 are not subjected to forces caused by the rotation of the cable roll 330. An electric signal which is to be led into the wires inside the sheathing of the cable is led into the fixed part 484 of the slip ring, from there into the movable part 482 of the slip ring, and from there through the wires 486 coming out of the movable part 482 of the slip ring into the plug 487, from there into the socket 488, where the plug 487 is inserted, and then into the wires inside the sheathing of the cable 370, which are attached to the socket 488.

(47) The cable 370 is guided by the cable guide rolls 420 and 425. The roll 425 is arranged such that a portion of the cable 370 which is unwound from the cable roll 330 is guided between the side portions of the roll 420 and the roll 425. In this way, the cable can be lead out of the winch without passing sharp edges. In addition, the friction force exerted on the cable 370 is kept low.

(48) Attached to the cable is a magnet 490. In addition, a magnet sensor 495, in particular, a hall sensor, or a reed sensor, is attached to the framework 310 of the winch. The magnet sensor is attached at a location of the framework 310 of the winch where the cable 370, in particular the magnet 490 attached to the cable 370, comes close enough to the magnet sensor 495 that the magnet sensor 495 can sense the magnet 490 attached to the cable 370 if the magnet 490 is moved close to the magnet sensor 495 by winding or unwinding the cable 370.

(49) FIG. 4c illustrates a cross-section of an exemplary cable 370 of a winch according to the invention. The cable comprises a sheathing 472, where electrically conducting wires 474, surrounded by an isolating material 476, are embedded. The cross section of the sheathing 472 is rectangular in shape, with rounded-down corners. In the illustrated embodiment, six electrically conducting wires are embedded in the sheathing, wherein the six wires are arranged in two groups of three wires each. The two groups of wires are located in a left and a right portion of the sheathing 472. At or near the center of the sheathing, a thread 478 made of resilient material is embedded to support a high weight attached to the cable. In particular, the central thread 478 may be made of non-stretchable material so as to prevent an extension of the cable if a high weight is attached to the cable 370. In an embodiment, the central thread 478 may be made from aramide yarn.

(50) FIG. 5 illustrates an example of a circuit board 360 in a winch according to the invention and components of the winch which are electrically connected to the circuit board. The circuit board 360 carries at least one microprocessor which is configured to process data provided from the devices connected to the circuit board. The microprocessor may further be configured to cause signals to be sent to at least one of the devices connected to the circuit board.

(51) There is an electrical connection 521 from the circuit board 360 to the electric motor 320. In this way, the electric motor 320 is supplied with electric power, and/or with control data. Moreover, an electric wiring 591 exists between the encoder 390, which is configured to provide data referring to the rotational motion of the cable roll to the circuit board. Using this electric wiring 591, data provided by the encoder 390 can be received by circuitry on the circuit board 360. Further, there is an electric connection 551 between the circuit board 360 and the potentiometer 395 to obtain data provided by the potentiometer 395, in particular data specifying the position of the cable roll 330 of the winch relative to a start position.

(52) An electric connection 581 is provided between the circuit board 360 and the slip ring 380. This electric connection 581 comprises wires for electric power and/or data which are provided to an electric device which is attached to the cable 370 of the winch using the clip ring 380. Power and/or data to be sent to an electric device attached to the cable of the winch is provided by circuitry on the circuit board via electric wires to the slip ring 380. Furthermore, there is an electric connection 556 to a sensor 495 in the winch, in particular, a magnet sensor. In this way, circuitry in the circuit board receives information if a magnet, in particular, a magnet attached to a particular location on the cable, is sensed by the sensor 495. In this way, circuitry on the circuit board 360 may be enabled to stop operation of the motor 320, in particular, stop its power supply, if a particular location of the cable marked by the attached magnet is sensed by the sensor 495. There is also an electric connection 558 to a light source 557, in particular, to a LED (light emitting diode), which is controlled by circuitry on the circuit board 360 to provide information about a state of operation of the winch.

(53) The circuit board 360 also has electric connections 547, 548 to an interface 342, in particular, to the data portion 342 of an interface, in particular, to an interface to a DMX bus. Using these electric connections 547, 548, the circuitry on the circuit board is provided with instructions concerning the requested operation of the winch received by the data portion 342 of the interface, and/or instructions concerning the behavior of an electric device electrically connected to the cable of the winch. Alternatively or in addition, the winch may be supplied with electric power by the power portion 341 of the interface. The electric power received by the interface 341 may be used for the operation of the circuitry on the circuit board. Alternatively or in addition, the electric power may be used to permit operation of electric devices in the winch and/or of electric devices which are attached to the cable of the winch. An electric component in the winch may be provided with electric power via an electric connection between the electric component and the circuit board. Alternatively or in addition, a component of the winch, in particular, the electric motor 320 or the transformer 350, may be supplied with electric power from the power portion 341 of the interface.

(54) The data portion 342 of the interface comprises an incoming part 545 and an outgoing part 546. In this way, the interface may be connected to a bus system like a DMX bus. In particular, DMX data may be received by the incoming part 545 of data portion of the interface. Received DMX data may be forwarded by means of electric connections 547 from the incoming part of the interface 545 to circuitry on the circuit board 360. DMX data received at the incoming part 545 of the interface may be provided, using electric wiring 547, 548, from the incoming part 545 to the outgoing part 546 of the data portion 542 of the interface.

(55) The circuit board 360 further carries a set of dip switches 362 and dials 364. By setting the dip switches 362 in a particular way, the behavior of the circuitry mounted on the circuit board, in particular, of the microprocessor, can be controlled. The dials 364 can be set to particular values to specify the address of the winch on the bus system connected to the interface 342, in particular, the address of the winch on a DMX bus.

(56) FIG. 6 illustrates a view onto the bottom of an exemplary embodiment of a winch according to the invention. Here, the framework of the winch is surrounded by a solid protective shell 620. At the bottom of the protective shell 620, there is an opening 610. Through the opening 610, the cable 370 hangs out of the protective shell of the winch. Through the opening 610, the cable guide rolls 420 and 425 are visible. At a side of the opening 610, there is a status LED 557 which informs a user about the operational mode of the winch. Further, a magnet sensor 495 is mounted at one side of the opening 610. Moreover, a magnet 490 is attached to the cable 370. If the cable is wound into the protective shell 620 through the opening 610, the magnet 490 passes the magnet sensor 495. The magnet sensor 495 may then send a signal indicating that the magnet 490 is sensed to circuitry controlling the winch. In this way, the circuitry can ensure that the cable is not wound up such far that the attached magnet 490 is pulled into the winch.

(57) FIGS. 7 a-d illustrate views of an example of an embodiment of a winch according to the invention. As illustrated by FIG. 7a, the winch is covered by a protective shell 620. A clip 315 is mounted on top of the winch and serves to attach the winch to a kind of support. In the upper part of the winch, plugs 342 of an interface of the winch are lead out of the protective shell. In an embodiment, the interface 342 comprises two plugs designed for incoming and outgoing data of a DMX bus. At the bottom of the protective shell 620, the cable 370 of the winch hangs out of the protective shell 620 through an opening in the shell 620.

(58) As is also illustrated in FIGS. 7 b-d, which show an end portion of the cable 370, a magnet 490 is attached to the part of the cable 370 which hangs out of the protective shell 620. Near the magnet 490, a pull relief 740 is pinned on the cable 370. A plug 750 is fastened to the end of the cable 370. The plug 750 is configured to provide an electrical connection to wires inside the cable 370. The input lead 755 of a lamp 780 has a corresponding plug 756 at its end, and the plug 756 at the end of the input lead 755 can be plugged into the plug 750 at the end of the cable to establish an electric connection between the lamp and the wires inside the cable 370 of the winch. The lamp 780 may be mechanically attached to the pull relief 740 via a connection ring 745. The pull relief 740 permits passing on the weight force of the lamp 780 to the cable 370 without putting mechanical stress to the electrical connection between the plug 750 at the end of the cable 370 and the plug 756 at the end of the input lead 755 of the lamp 780. The pull relief 740 has the form of a ladder with a number of rungs, in particular, 4 rungs. To achieve the effect of passing on weight force of the lamp 780 from the connection ring 745 to the cable 770, the cable 770 is threaded through the rungs of the pull relief 740, in particular, first from one end of the pull relief 640 to the other, and then in opposite direction, as illustrated in FIGS. 7b-d.

(59) FIG. 8 illustrates a particular embodiment of a system of winches according to the invention. The winches 810, 811, 812, 813 and 814 are attached to a pole 840 by a clamp. The pole is connected to a truss 850 using clamps 851, 852. The winches 810, 811, 812, 813 and 814 are connected to a system controller, for example, a PC. Each of the winches has a DMX input plug and a DMX output plug. The system controller is electrically connected to the input plug of one of the winches, for example, of winch 810. The winches 810, 811, 812, 813 and 814 are daisy chained so that each winch has access to the DMX bus and thus, the possibility to receive data sent by the system controller. Each winch comprises dials where an address of the winch can be set. Each winch uses the address specified by its dials to determine which of the data on the DMX bus are directed to it.

(60) At the cables 820, 821, 822, 823, and 824 of the winches 810, 811, 812, 813 and 814, electric devices 830, 831, 832, 833 and 834 are electrically connected. In a particular embodiment, the system controller issues instructions to the winches which cause an addressed winches to wind or unwind its cable roll such that the respective connected electric device is at a distance from the winch which is different for each of the winches.

(61) In particular, the respective distance of the electric devices 830, 831, 832, 833 and 834 from the corresponding winches 810, 811, 812, 813 and 814 may be determined by the system controller as value of a chosen function of one variable. If the variable is the distance of the clamp which attaches the winch to the pole 840 from an end of the pole, then the system controller may send instructions to the winches wherein the requested distance between the connected electric device and the pole 840 is the value of the chosen function, wherein the distance of the clamp which attaches the respective winch on the pole from an end of the pole is taken as argument.

(62) In this way, the requested locations of the requested devices may mark points on a graph of the chosen function.

(63) For example, if the chosen function is the equation of a straight line, then the locations of the electric devices 830, 831, 832, 833 and 834 mark locations on a straight line. Such a situation is illustrated by the dashed lines in FIG. 8. In another example, if the chosen function is the square function, then the locations of the electric devices mark points on a parabolic curve. Other functions, in particular, functions with more than one argument, may be used. For example, if the winches fastened to a truss with a two- or three-dimensional distribution instead of being lined up along a pole 820, the chosen function may be a function of two or three arguments. In this case, the locations of the electric devices mark points on the graph of a two- or three-dimensional function.

(64) It is to be understood that the different parts and components of the winch and system described above can also be implemented independently of each other and can be combined in different form. Furthermore, the above described embodiments are to be construed as exemplary embodiments only.