Bale wrapping device
The bale wrapping device uses an electromagnet to adjust the restraining effect based on movement state, addressing false triggering issues and ensuring safe and reliable operation.
Patent Information
- Application Number
- DE102023135243
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-14
- Publication Date
- 2025-06-18
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
The present invention relates to a bale wrapping device according to the preamble of claim 1 and to a method according to the preamble of claim 15.Bale wrapping devices are used to wrap bales of crop material such as grass, straw, hay, corn or the like with a wrapping material. According to a functional principle known in the prior art, the bale wrapping device has a wrapping unit which can be driven to rotate about a wrapping axis and applies the wrapping material to the bale of crop in a rotational movement guided circumferentially around the bale of crop material. A switching unit leading the winding unit serves to prevent injuries to humans and animals and / or damage to the winding arm and / or the bale-winding device. Upon contact with an obstacle, the switching unit initiates a safety measure which is provided to stop the winding unit in its rotational movement before it reaches the obstacle. The safety standard DIN EN ISO 4254-14:2016 proposes that a pulse energy for triggering the switching unit must not exceed a value of 20 Joules. The standard defines this triggering energy for a stationary operation. However, it has been found in practice that with the suggested triggering energy of 20 joules, false triggerings can occur during a driving operation. The false triggerings often result in undesired interruptions of the winding process during field operation.It is an object of the invention to provide a bale wrapping apparatus which offers both increased reliability and safety during the wrapping of crop bales.The object is achieved with a bale wrapping device having the features of independent claim 1, with a bale wrapping device having the features of independent claim 8, and with a method having the features of independent claim 15.For this purpose, a bale wrapping device for wrapping a crop bale with a wrapping material is provided. The bale wrapping device has a frame, at least one wrapping unit, which can be driven to rotate about a wrapping axis in a rotational direction relative to the frame, for delivering the wrapping material to the crop bale, at least one switching unit, which leads the wrapping unit in the rotational direction and is provided for detecting an obstacle, and a holding device, which is configured to hold the switching unit in a basic position, wherein the switching unit can be deflected from the basic position into a triggering position by overcoming a restraining effect of the holding device relative to the wrapping unit, whereby a safety measure of the bale wrapping device can be triggered.The bale wrapping device serves to wrap bales of crop material. Various embodiments of the bale wrapping device can be used. In one embodiment, the bale wrapping device is designed as a self-propelled working machine with its own travel drive and chassis. In another embodiment, the bale wrapping device is designed as a towed working machine, which does not have its own travel drive and is instead towed by a towing vehicle such as a tractor. This also includes, for example, the option that the bale wrapping device is attached to a baler which is in turn pulled by the tractor. In yet another embodiment, the bale wrapping device is designed as an attachment that does not have its own chassis and can be attached to a vehicle in order to be carried by the latter. For example, the attachment can be attached to a towing vehicle on the front and / or rear side, in particular by means of a three-point hydraulic system. There is also the possibility of being mounted on other vehicles, such as a front loader, a telescopic loader or an excavator, just to name a few examples.The invention is furthermore not restricted to machine types which are provided exclusively for wrapping bales of crop material, but it also extends to agricultural working machines in which such a bale wrapping device is integrated. Thus, the bale wrapping device can be part of a baler, for example a so-called press-wrapping combination, which has at least one pressing device for pressing the bale of crop material and a transfer device for transferring the bale of crop material from the pressing device to the bale wrapping device. The pressing device and the bale wrapping device can be connected via a common frame in this embodiment. It is also conceivable for the crop bale to be wound around at the same location at which it was also pressed, so that the pressing device and the bale winding device are not clearly separated from one another in space, and a transfer device is omitted.Wrapping the crop bale can be useful for various reasons. Thus, the wrapping can serve to protect the crop bale from weather influences such as rain. The wrapping can also serve to keep the shape of the crop bale by preventing the crop bale from breaking down as a result of the wrapping. Furthermore, the wrapping can serve to promote fermentation processes in the crop bale, such as during the production of silage. Depending on the intended use, different requirements can be imposed on the winding material. Accordingly, the winding material can have different properties and / or characteristics. The winding material is preferably configured in the form of a web, for example in the manner of a film, a cloth and / or a net. The winding material can, however, also be configured in the form of a thread or yarn and / or wire or in the form of a band, for example as a plastic band.The frame is to be considered a supporting structure which can support and / or hold together various devices and / or assemblies of the bale wrapping apparatus. If the bale wrapping device has a chassis, this can be suspended from the frame. The frame is advantageously formed rigid in itself. It can be formed in one piece or have a plurality of components which can be joined together, for example, by welding and / or screwing. It will be appreciated that the exact composition and construction of the frame may vary depending on the embodiment of the bale wrapper. The winding unit can be driven to rotate relative to the frame. In particular, it can be supported directly or indirectly by the frame. In this case, the weight force of the winding unit and the resulting torques are absorbed by the frame.The rotational movement of the winding unit serves to wind the crop bale with the winding material. It is defined by the winding axis. The winding axis can be arranged in particular in such a way that it passes through a central region of the same when the crop bale is picked up. Although other orientations are possible, the winding axis preferably extends in an approximately vertical direction, i.e. it extends parallel to a vertical axis of the bale winding device or at an angle of at most 30° thereto. The rotational movement of the winding unit serves to deliver the winding material to the crop bale. During the rotational movement, the winding material is guided at least in regions circumferentially around the crop bale and applied to the latter.The winding material can be arranged at a storage location separate from the winding unit, from which it can be drawn off by the winding unit. However, it is preferred that the winding unit is designed to support the winding material. In this embodiment, the winding material is usually arranged on the winding unit at a height with respect to the vertical axis which corresponds at least partially to a position of the crop bale.The winding material can be provided in various ways depending on the configuration. It is preferred that the winding material is provided rolled up on a roll. By the rotational movement of the winding unit relative to the crop bale, to which a partial section of the winding material already adheres, the winding material is drawn off and / or unrolled. The winding unit can additionally be equipped with a prestretching system which is provided to subject the winding material to a prestress during the pulling and / or unrolling. As a result, the winding material can be stretched, as a result of which, for example, an adhesive applied to the winding material can be activated. Also, by the prestretching, a constant contact pressure of the winding material on the crop bale can be achieved.The crop bale to be wrapped is a bale of crop material pressed by a suitable pressing device. The invention is in principle not restricted to a size and / or shape of the crop bale. Accordingly, it can be in particular a cylindrical round bale, but also, for example, a cuboidal crop bale.The bale wrapping device usually has a wrapping table which is provided to pick up the bale of crop material at least during the wrapping process. The bale wrapping device can have a lifting device which makes it possible to lift the crop bale approximately from the ground and transfer it to the wrapping table. It is also conceivable for the crop bale to be picked up from the ground directly by the winding table. In the case of a press-winding combination, the crop bale can also be transferred to the winding table by the above-mentioned transfer device. The winding table can have at least one drive means in order to set the crop bale in motion at least during the winding process. In particular, the drive means can be provided to set the crop bale in rotation about an axis deviating from the winding axis. The axis about which the crop bale can be rotated can be an axis of symmetry of the crop bale. As a result, the winding unit can advantageously wind around the crop bale with differently oriented tracks of the winding material. This drive means can be formed, for example, from a roller and / or a belt which are in contact with the crop bale during the winding process in order to set it in rotation.In principle, it is possible to distinguish between two winding processes. Thus, the pulling off of the winding material and the discharge to the crop bale can be carried out on the one hand by means of a rotational movement of the crop bale and on the other hand by means of a rotational movement of the winding unit about the winding axis with an optional additional rotational movement of the crop bale. The bale wrapping device of the generic type is designed in particular for carrying out the latter of the two mentioned wrapping processes.The switching unit serves to detect an obstacle that is located in a movement range of the winding unit, in particular before a collision with the winding unit takes place. Therefore, it is arranged on the bale wrapping device in front of the wrapping unit. The obstacle can be a person or an animal who enter the movement range of the winding unit. It can also be an object by which there is a risk of collision. It can also be, for example, the bale of crop material if it unintentionally moves away from the winding table during the winding process.The switching unit can be deflected from the basic position into the release position, wherein the deflection takes place relative to the winding unit. The basic and release positions are therefore to be regarded as positions which the switching unit can assume relative to the winding unit. For the deflection, the switching unit is mounted rotatably and / or displaceably and / or is formed in a flexible manner. This property of the switching unit serves to protect the obstacle as well as the switching unit even upon contact by yielding return. The deflectable nature of the switching unit is also used to trigger the safety measure. The safety measure is intended to avoid and / or at least limit injury and / or damage risks due to a collision with the winding unit.The holding device serves to hold the switching unit in the basic position as long as no appreciable external forces or torques act on the switching unit. This holding function is carried out at least by the exertion of the restraining action on the switching unit, since the deflection out of the basic position takes place counter to the restraining action of the holding device. The restraining effect can also be understood in this context as a resistance which opposes the deflection. For example, the restraining effect may be based at least in part on a resistance to elastic deformation. However, it can also be a resistance to a translatory and / or rotatory movement of the switching unit. The restraining effect is generally based at least on a restraining force and / or a restraining torque. The restraining force and / or the restraining torque is in particular a sum of forces and / or torques which are exerted by the holding device on the shift unit. If the deflection of the switching unit is realized by elastic deformation, the restraining effect is also based at least on an elastic restoring force and / or an elastic restoring moment.The restraining effect acts on the switching unit at least during the deflection from the basic position into the triggering position. In particular, the retaining effect can act on the switching unit in the basic position, in the triggering position and / or in any desired position between the basic position and the triggering position. Likewise, the restraining effect can also only act during the deflection into the release position. It can also act only initially, i.e. for a virtually infinitely small deflection travel and / or for a virtually infinitely short deflection time, during the deflection. It can also act on the switching unit only in sections or continuously during the deflection.The bale wrapping device is characterized in that the holding device has at least one electromagnet which is designed to at least influence the restraining effect.The electromagnet is designed to generate a magnetic field. A magnetic force effect of the magnetic field allows the restraining effect to be influenced. For this purpose, only one component has to be designed to react to the magnetic field. Advantageously, such a component can be at least partially ferromagnetic. In particular, the distance of the component from the electromagnet in the release position can differ from the distance in the base position. The electromagnet can be arranged, for example, stationary with respect to the winding unit, while the said component is arranged stationary with respect to the switching unit and forms, for example, at least a part of the switching unit. Conversely, however, the component could also be arranged stationary with respect to the winding unit and the electromagnet could be arranged stationary with respect to the switching unit. Other possibilities are also available. For example, the electromagnet can magnetize two ferromagnetic components, so that they attract one another and thus contribute to the restraining effect.The restraining effect can be influenced in various ways by the electromagnet. Thus, it can be provided that the electromagnet constantly influences the restraining effect over a longer period of time. Accordingly, the electromagnet can be used as a quasi-permanent magnet. However, the use of the electromagnet is preferably effected in a dynamic manner. That is, the generated magnetic field is adjusted over an operating period. The adjustability of the magnetic field can be used for adjusting the restraining effect. In general, the magnetic field generated by the electromagnet, in particular a strength of the magnetic field, is dependent on an electric current flowing through the electromagnet. An effect of the electromagnet is therefore variable by a change in the electric current.The restraining effect to be adjusted can be useful or advantageous for several reasons. This applies in particular to changing operating and / or ambient conditions of the bale wrapping device. The restraining effect can accordingly be adjustable, or even optimized, on the basis of various conditions and / or goals. Thus, on the one hand, the restraining effect can be adjusted with a view to ensuring the highest possible safety during the winding process. This can be realized, for example, by a sensitive and / or rapid triggering of the switching unit. The sensitivity of the release depends on the restraining action. The lower the restraining effect, the higher the sensitivity of the switching unit. As a result, the sensitivity can be adjusted by adjusting the restraining effect. However, with too high a sensitivity, false triggerings can increasingly occur. False triggerings are to be understood in this context as unintentional triggerings of the switching unit, that is to say in particular triggerings without obstacle contact. In an advantageous embodiment, the restraining effect for the gentle obstacle contact is set sufficiently low and at the same time sufficiently high to reliably prevent false triggerings.The electromagnet can optionally be designed to increase and / or reduce the restraining effect. It can furthermore be provided that the restraining effect is applied exclusively by the electromagnet. In this case, the restraining effect by switching off the electromagnet can also be completely omitted. Furthermore, it can be provided to use a plurality of such electromagnets for influencing the restraining effect.The use of the electromagnet generally offers many further advantages. In particular, in comparison with a motor solution, a number of movable parts, a required installation space and a maintenance outlay are very low. In addition, the electromagnet has a long service life and low sensitivity to interference, so that the holding function of the holding device is reliably ensured.In a preferred embodiment, the electromagnet is designed to generate an electromagnetic force acting on the switching unit relative to the winding unit, which can be varied in order to at least influence the restraining effect. Depending on the direction of force of the electromagnetic force, this can contribute to increasing or decreasing the restraining effect. That is, the electromagnetic force may contribute negatively or positively to the restraining effect. Furthermore, it is possible that the restraining effect is based exclusively on the electromagnetic force. The electromagnetic force acts on the switching unit relative to the winding unit. It can, for example, generate an attraction of the switching unit to the winding unit or a repulsion from the winding unit. Strictly speaking, due to the principle "actio=reactio" the electromagnet generates a couple of forces, wherein a force acts on the switching unit and an equally large opposing force acts directly or indirectly on the winding unit. It can also be said that the electromagnetic force acts between the switching unit and the winding unit. The electromagnet can be connected at least indirectly to the winding unit or else to the switching unit. It can also be integrated into one of the units. The electromagnetic force may be based on a magnetic interaction with the respective other unit or with a component connected thereto. The electromagnetic force can be changed, as a result of which the restraining effect can also be influenced and changed. More specifically, the electromagnetic force is variable with the position of the switching unit remaining the same. In particular, it can be variable while the switching unit is in the basic position. Depending on the structural design, the electromagnetic force can act on the switching unit in an attracting or repulsive manner. It can likewise act on the winding unit in an attracting or repulsive manner.The electromagnetic force can be connectable by switching on the electromagnet. In this embodiment, the electromagnet exerts the electromagnetic force in the ON state, while it exerts no force in the OFF state. In addition or as an alternative to the pure switching on and / or off, an adjustment of the electromagnetic force is also possible, so that different values of the electromagnetic force that differ from zero can be adjusted. The electromagnetic force can be adjustable continuously and / or stepwise. For this purpose, only the current flow through the electromagnet has to be adapted. By reversing the polarity of the current flow, it is also possible to change the direction of force of the electromagnetic force. Accordingly, the electromagnetic force of the electromagnet can act selectively attracting or repelling between the winding unit and the switching unit in order to influence the restraining effect. In order for the electromagnetic force to act in a repulsive manner, the electromagnet must cooperate with a further magnet, wherein the two magnets face poles of the same name.The influence of the retaining action by the electromagnet can, as already described, be achieved in principle by an attracting or repulsive action. In this case, the electromagnet can be configured in particular to have an attracting and / or repulsive effect on the winding unit or the switching unit.Depending on the design, different local arrangements of the electromagnet are possible. Thus, in an advantageous embodiment, the electromagnet can be arranged on the switching unit. In this embodiment, it can be configured to exert the electromagnetic force on the winding unit. In an equally advantageous embodiment, the electromagnet can be arranged on the winding unit. In this embodiment, the electromagnet is preferably designed to exert the electromagnetic force on the switching unit. The electromagnet can also act on a component which is not surrounded by the switching unit or the winding unit or can be arranged on the latter. This can be in particular a component which is rigidly or flexibly connected to the switching unit or the winding unit. A mechanical force transmission can be effected between the component and the switching unit or winding unit by means of the connection, as a result of which the electromagnetic force also acts on this unit.It is also preferred that the holding device comprises, in addition to at least one electromagnet, a force means which is designed to generate an additional force acting on the switching unit relative to the winding unit, wherein the additional force at least influences the restraining effect. The force means is provided in addition to at least one electromagnet, which, however, does not exclude it also being formed as an additional electromagnet. The electromagnetic force and the supplemental force represent different forces in this respect, although the supplemental force may also be based on a magnetic interaction. The force means can be arranged, for example, on the winding unit and / or on the switching unit. It can be formed in one part or in multiple parts. In the latter case, it can be arranged partly on the winding unit and partly on the switching unit.Depending on the structural design, it is preferred that the additional force of the force means is oriented at least partially in the force direction of the electromagnet force of the electromagnet or acting against the force direction. Accordingly, the additional force can be provided to assist the action of the electromagnet by acting in the direction of force of the electromagnet force or to reduce it by acting counter to the direction of force of the electromagnet force. In the event of a provided change in direction of the electromagnet force, by polarity reversal of the electromagnet, the additional force can act temporarily in the direction of force and temporarily counter to the direction of force.Both the electromagnetic force and the additional force can be provided to subject the shift unit to a torque. The restraining effect can be based in particular exclusively on the torque introduced by the electromagnetic force and the additional force. The electromagnetic force and the additional force can also have different force application points.It is preferred that the influence of the force means on the restraining effect is independent of the influence of the electromagnet. In particular, the force means can operate independently of the electromagnet. The electromagnet requires a current flow for operation in order to apply the electromagnetic force. Advantageously, even in the event of a power supply to the electromagnet being omitted, the restraining effect can be at least partially maintained by the force means.It is also preferred that the force means is designed to influence the restraining effect independently of an operating state of the bale wrapping device, and / or that the force means is designed as a passive force means. Passive in this context means that it can be operated without an, in particular permanent, energy supply. The switching unit can accordingly be acted upon with the additional force independently of current operating and / or environmental conditions. As a result, the influence of the force means on the restraining effect remains unchanged at least during the winding process. This means that, in the case of a positive contribution of the force means to the restraining effect, said force means is permanently present at least to the extent brought about by the additional force even in the case of changing operating conditions.Various embodiments of the force means can be used within the scope of the invention. It is preferred that the force means has at least one spring, a magnet and / or a mechanical lock. The force means can in particular have exactly one spring, one magnet or one mechanical lock. In addition, a combination of spring, magnet and / or mechanical locking in any number is possible.The spring can be designed as a compression spring or as a tension spring. The spring can likewise be designed as a torsion spring. In this embodiment, the additional force is based at least on a spring restoring force and / or a spring restoring moment of the spring and serves to influence the restraining effect.The magnet can be designed as an additional electromagnet. Preferably, however, it is designed as a permanent magnet, so that it operates independently of a power supply. The restraining effect can be influenced by the magnet by applying a magnetic force to the switching unit.Preferably, the mechanical locking device has at least two latching elements which are provided for the purpose of being connected in a locking manner by latching. The latching serves to hold the switching unit in the basic position. The latching elements are unlocked when the switching unit is deflected from the basic position into the release position. The unlocking is effected against a locking force of the latching elements. In this embodiment, the additional force is based at least in part on the locking force of the mechanical lock.Spring, magnet and / or mechanical locking are provided to at least influence the restraining effect by exerting the additional force. In the case of a combination and / or a plurality of spring, magnet and / or mechanical locking, the additional force can also be considered as a sum of the forces of the spring, of the magnet and / or of the mechanical locking. In all of the above-mentioned embodiments, the force means is capable of at least influencing the restraining action independently of the electromagnet.According to an advantageous embodiment, the bale wrapping device has an adjusting device which is configured to automatically adjust the restraining effect depending on a movement state of the frame relative to a ground. In particular, the actuating device can actuate the electromagnet depending on the state of movement. The automatic setting can comprise the simple switching on and / or switching off of the electromagnet as a function of the state of movement. Additionally or alternatively, the adjusting device can bring about an automatic adjustment of the strength and / or the direction of force of the electromagnetic force.Depending on the local arrangement and / or mode of action of the electromagnet, a different setting of the restraining effect can be expedient. That is to say that the automatic setting of the restraining effect can be dependent on whether the electromagnet is arranged on the switching unit, winding unit or another component and / or whether the electromagnet acts in an attracting or repulsive manner.It is considered in this connection to be a self-contained invention to provide a bale wrapping apparatus according to the preamble of claim 1, which comprises an adjusting device adapted to automatically adjust the restraining effect depending on the state of movement of the frame relative to the ground.In embodiments of the bale wrapping device which have their own chassis for supporting with respect to the ground, the state of movement is preferably a driving state of the bale wrapping device. In embodiments which do not have their own chassis but are carried by the towing vehicle, the movement state can be determined by a driving state of the towing vehicle.The bale wrapping device can have one or more control units which are configured to process signals and to output commands to actuators and / or motors. In this case, the actuating device can have, for example, at least one control unit or can be formed by at least one control unit.Due to the dependence on the movement state, the restraining effect in a moved state differs from a non-moved state of the frame. The moved state describes a state in which the frame has a relative speed with respect to the underlying surface. In the non-moving state, the frame does not have a relative speed with respect to the underlying surface. The relative speed can be, in particular, a travel speed of the bale wrapping device and / or of the tractor.In addition to the automatic setting as a function of whether a relative speed of the frame different from zero is present, the setting can also be effected as a function of the relative speed, in particular an absolute value of the relative speed. That is, the adjusting device can be configured to set different restraining effects for different relative speeds different from zero. In particular, it can be configured to set different restraining effects for different absolute amounts.As already described, the restraining effect is optimally dimensioned such that the obstacle contact is gentle, the safety measure is safely triggered and, at the same time, false triggerings are avoided. The operating and / or ambient conditions differ substantially in the moving and non-moving state. In the non-moved state, persons who may inadvertently move into the movement range of the winding unit are to be expected, for example. When the machine is moving, it is again more likely that the crop bale unintentionally releases from the bale wrapping device. Furthermore, when the machine is moving, false triggerings can occur more frequently, in particular when irregularities in the ground are traveled over and / or the bale wrapping device is moved in a slope position. It is therefore expedient to automatically adapt the restraining effect to the setting which is optimum for the current state of movement.The automatic setting also has the advantage of relieving the operator of the bale wrapping device. As soon as the corresponding movement state is detected, the automatic adaptation of the restraining effect takes place. The state of movement can in principle be detectable in different ways. For example, a rotational speed sensor may be provided on a traction drive, a wheel or a transmission in order to detect the movement state. For detecting the state of movement, a GPS sensor and / or an acceleration sensor can also be provided. One or more such sensors may be present. A sensor can be associated with the bale wrapping device and / or the towing vehicle.The automatic setting of the restraining effect can be effected according to predetermined values. The values can be stored and readable, for example, in a memory. Alternatively or additionally, they can also be input by the operator of the bale wrapping device and / or can be called up by a remote data center.In order to deflect the switching unit from the basic position into the triggering position, a triggering energy is necessary. Since the restraining effect is to be overcome for triggering, there is in principle a connection between the restraining effect and the triggering energy. The higher the restraining effect, the higher the required release energy. As a rule, the triggering energy is a pulse energy which is transmitted to the switching unit on contact with the obstacle in order to deflect the switching unit into the triggering position. It is advantageous to set the triggering energy in the non-moving state to a standard-compliant measure. In particular, the restraining effect can be set such that the triggering energy is not more than 20 J. For the moved state, however, the restraining effect can be adapted to the currently prevailing operating conditions.It is particularly preferred that the restraining effect in a moved state of the frame is increased compared to an unmoved state of the frame. In the non-moved state, the restraining effect is accordingly lower than in the moved state. The resistance is thereby increased in the moved state and the switching unit is set to be less sensitive. As a result, the number of false triggerings in the moved state can be reduced, wherein at the same time high safety is produced in the non-moved state by the sensitive triggering.In principle, it would be possible to change the basic position in order to adapt the sensitivity of the triggering and / or the triggering energy. However, it is preferred that the restraining effect is adjustable independently of the basic position of the switching unit and / or with the basic position remaining the same. This can bring about a change in the sensitivity and / or the triggering energy without having to accept a change in the basic position.It is furthermore preferred that the restraining effect is adjustable as a function of at least one additional parameter. By using the additional parameter, the triggering behavior of the switching unit can be further optimized. This can further increase the reliability and / or the safety. For example, a ground inclination can be used as an additional parameter. In particular also in combination with the setting as a function of the relative speed of the frame, a finer and / or more optimum setting of the restraining effect can thereby be effected. When driving over ground waves at a high travel speed and / or when driving over a steep slope, false triggerings can be better avoided with the aid of this adjustment possibility.It is preferred that the switching unit has a switching arm pivotable about a pivot axis between the basic position and the release position. In particular, the switching arm can form the switching unit. Preferably, the winding unit also has a winding arm which can be driven about the winding axis. In particular, the winding arm can form the winding unit. The winding arm and / or the switching arm extend in particular at least in sections radially outwards from the winding axis and / or are oriented at least in sections parallel to the winding axis.In operation, the switching unit leads the winding unit in the rotational direction. For this purpose, it is preferred that the switching arm is arranged so as to lead the winding arm in the rotational direction. The switching arm is also preferably mounted such that it can be pivoted about the pivot axis relative to the winding arm. In the release position, the switching arm can be arranged in particular closer to the winding arm than in the basic position.In an advantageous embodiment, the bale wrapping device can have a plurality of wrapping units and / or switching units. It is particularly preferred that exactly one switching unit is provided for each winding unit. In the embodiment as a winding arm and switching arm, the switching arm is arranged in front of and / or pivotably mounted with respect to the winding arm assigned to it.It is preferred that a restraining torque is introduced about the pivot axis by the electromagnetic force and / or the additional force, wherein the restraining torque acts in the opposite direction to the pivoting of the shift arm from the basic position into the triggering position. The switching arm can thereby retract upon contact with the obstacle by overcoming the restraining moment by pivoting about the pivot axis. In this embodiment, the restraining effect is based at least partially, in particular exclusively, on the restraining torque which is introduced by the electromagnetic force and / or the additional force.The safety measure may include various operations. Thus, the safety measure can be provided to emit a warning signal to the operator of the bale wrapping device and / or to bring about a control of the bale wrapping device and / or of the towing vehicle. It is particularly preferred that the safety measure is provided at least for at least braking the winding unit. The braking of the winding unit preferably takes place until the winding unit is at a standstill. In particular, it can be provided to stop the winding unit before reaching a contact point of the switching unit with the obstacle in order to prevent injuries and / or damage.In the aforementioned embodiment, the triggering of the safety measure takes place by deflecting the switching arm into the triggering position. The triggering position can be an end position in a pivot range of the switching arm or any position between the base position and the end position.The deflection into the triggering position can be detected by mechanical and / or electronic means. Accordingly, the bale wrapping device can have a release mechanism, wherein the release mechanism can be actuated by adjusting the switching arm into the release position. The mechanism can comprise, for example, one or more levers which, when actuated, bring about the braking of the winding unit. For this purpose, the levers can activate a valve and / or a brake, for example.Alternatively or additionally, the bale wrapping device can have a sensor which is provided to detect a position of the switching arm relative to the wrapping arm and, in particular electronically, to output a sensor signal to the actuating device as a function of the detected position. In this embodiment, the actuating device is configured to process the sensor signal and to bring about the execution of the safety measure by outputting control commands.The position detection by the sensor can be effected contactless, in particular inductively and / or capacitively. Likewise preferably, the sensor can have an actuating means which can be actuated by the switching unit when it is adjusted from the basic position into the triggering position, wherein the safety measure can be triggered upon actuation, in particular by outputting the sensor signal. The actuating means can be designed in particular as a lever, slide or the like for this purpose.The actuating device of the bale wrapping device can be configured to process the signal and to bring about the execution of the safety measure by outputting control commands.The invention also provides a method of operating a bale wrapper. The bale wrapping apparatus has the features of the preamble of claim 1, which will not be discussed repeatedly herein.In the method according to the invention, it is provided that the restraining effect of the holding device is automatically adjusted depending on a movement state of the frame of the bale wrapping device. The automatic setting is preferably carried out by means of an adjusting device. The adjusting device can be assigned to the bale wrapping device. It can also be arranged separately from the bale wrapping device. In this case, in an embodiment of the bale wrapping device as an attachment or a towed machine, it can be assigned to a towing vehicle to which the bale wrapping device is attached or suspended.In the method, in particular the crop bale is wound around by the winding unit of the bale winding device during a winding process. During the winding process, the winding unit is driven to rotate about the winding axis in the rotational direction. In addition, during the winding process, the switching unit is held in the basic position by the holding device. The switching unit leads the winding unit in the rotational direction. It is thus likewise driven to rotate about the winding axis.As soon as an obstacle is detected by the switching unit during the winding process, the steps described below are carried out in particular in the method:• the switching unit is deflected from the basic position into the triggering position;• the restraining effect of the holding device is overcome when the switching unit is deflected; and• The safety measure of the bale wrapping device is triggered by the deflection of the switching unit into the release position.The method advantageously optimizes the restraining effect as a function of the state of movement. The switching unit can have a sensitive triggering in order to achieve a high level of safety in a non-moving state. For this purpose, the restraining effect in the stationary state is reduced. Furthermore, the reliability can be increased by increasing the restraining effect in a moved state in order to avoid false triggerings.The terms mentioned have already been explained above with reference to the bale wrapping device according to the invention. Advantageous embodiments of the method according to the invention correspond to those of the bale wrapping device according to the invention.The invention is described below with reference to figures. The figures are merely exemplary and do not limit the general inventive concept. They show FIG. 1 is a perspective view of a first embodiment of a bale wrapping device according to the invention; FIG. 2 is a partial perspective view of the bale wrapping device of FIG. 1; FIG. 3 is a partial perspective view of a second embodiment of a bale wrapping device according to the invention; FIG. 4 is a partial perspective view of a third embodiment of a bale wrapping device according to the invention; and FIG. 5 is a perspective partial view of a fourth embodiment of a bale wrapping device according to the invention.FIG. 1 shows a first embodiment of a bale wrapping device 1 according to the invention for wrapping a crop bale 2 with a wrapping material 41.The bale wrapping device 1 is in this case designed in the manner of a towed working machine. It has a frame 11 which is supported on a floor or subgrade 8 by means of wheels of a chassis 14. The bale wrapping device 1 has a hitching device 13 in the form of a drawbar, which is arranged on the front side of the frame 11 with respect to the longitudinal axis X and by means of which it can be suspended to a towing vehicle in order to be pulled by the latter.The bale wrapping apparatus 1 further comprises a lifting device 15 which is configured to lift the crop bale 2 from the ground 8 and to place it on a wrapping table 12.At least one winding unit 4 is provided for winding the crop bale 2. In this embodiment, the bale wrapping device 1 has two wrapping units 4, each of which is designed as a wrapping arm 42. Each of the winding arms 42 carries a roll with the web-shaped winding material 41 approximately at a height of the crop bale 2 arranged on the winding table 12. During the winding process, the winding arms 42 rotate about a winding axis W in a rotational movement which at least in regions rotates about the crop bale 2. When the winding arms 42 rotate, the winding material 41 is pulled off the rollers and applied to the crop bale 2, so that the latter is applied with the winding material 41.In order to grasp the entire surface of the crop bale 2 with the wrapping material 41, the crop bale 2 is additionally set in rotation about an axis of symmetry of the crop bale 2 during the wrapping process. In this example, the crop bale 2 is designed as a round bale and is oriented on the winding table 12 in such a way that its axis of symmetry extends approximately parallel to the transverse axis Y. For rotating the crop bale 2, the winding table 12 has a plurality of belts 122, which are driven by means of at least one drivable roller 121. By rotating the winding arms 42 about the winding axis W and rotating the crop bale 2 about the bale axis, the crop bale 2 is wound on all sides with the winding material 41. The winding axis W extends through a central region of the crop bale 2 and extends parallel to the vertical axis Z in this example.The bale wrapping device 1 has a wrapping drive 7 which is configured to drive the wrapping arms 42 in a rotational direction R. In the embodiment shown, the energy required for the drive is provided as a towed working machine by the towing vehicle, for example via a hydraulic supply.The rotational movement of the winding arms 42 defines a movement range of the bale wrapping device 1. Since the wrapping material 41 usually has a high intrinsic weight, there is a risk of damage and / or injury in the event of the winding arm 42 colliding with an obstacle that reaches the movement range. The bale wrapping device 1 has a switching unit 5 for each of the wrapping units 4, which is provided to detect the obstacle immediately before or as soon as it reaches the movement range of the associated wrapping unit 4.In this case, the two switching units 5 are each designed as a switching arm 53. Each of the switching arms 53 leads the winding arm 42 assigned to it in the rotational direction R. For this purpose, it is likewise driven by the winding drive 7 in the rotational direction R about the winding axis W.Since each of the switch arms 53 leads the associated winding arm 42, it can detect the obstacle before the winding arm 42 reaches it. Upon detection of the obstacle, a safety measure is triggered which is at least provided to brake the winding arms 42. A braking delay of the winding arms 42 is generally dimensioned such that the winding arms 42 stop before they reach a contact point of the switching arm 53 with the obstacle. The safety measure therefore prevents injuries and / or damage due to a collision of the obstacle with the winding arm 42. The switch arms 53 are also resiliently mounted to retract upon contact with the obstacle.The winding arms 42 and switching arms 53 each extend radially outwards in a horizontal section starting from the winding drive 7 and in a vertical section approximately parallel to the winding axis W and to the vertical axis Z in the direction of the base 8.The bale wrapping device 1 has a holding device 6, which is designed to hold the switching arm 53 in a basic position. The holding function of the holding device 6 is carried out by exerting a restraining effect on the switching arm 53 and serves in particular to fix it securely in the basic position when the bale wrapping apparatus 1 is approaching, accelerating and / or operating. The restraining action constitutes a resistance which opposes a deflection of the switching arm 53 out of the basic position. By overcoming the restraining effect, the switching arm 53 is moved from the basic position into a release position. To overcome the restraining effect, a triggering energy is required. The triggering energy required for triggering is determined by the restraining effect. In order that the impact of the switching arm 53 on an obstacle is gentle, the triggering energy should be as low as possible. For example, the triggering energy, as proposed by the safety standard DIN EN ISO 4254-14:2016, should not exceed a value of 20 J.Upon deflection of the switching arm into the triggering position, the safety measure is automatically triggered. For this purpose, a sensor signal is output by the switching unit 5 to an actuating device 3. The actuator 3 processes the sensor signal and outputs a control command to stop the winding unit 4. In this exemplary embodiment, the actuating device 3 is connected to the winding drive 7 by signal technology in order to actuate the latter.The adjusting device 3 is shown here in a simplified illustration alongside the bale wrapping apparatus 1, which, however, does not necessarily represent the actual arrangement. The adjusting device 3 can be arranged, for example, on the bale wrapping apparatus 1 or integrated therein. Alternatively, it can also be comprised, for example, by the towing vehicle and / or a remote computer system.The mode of operation of the holding device 6 is explained in more detail below with reference to FIG. 2. Figure 2 shows an enlarged partial view of the first embodiment of the bale wrapping apparatus 1 shown in Figure 1, the view being directed towards the holding device 6 and the wrapping drive 7. The winding arms 42 and switching arms 53 are shown here merely in a projection. In addition, a cover of the winding drive 7 is hidden from view in comparison with FIG. 1 in order to allow a better view of elements of the holding device 6 and the winding drive 7.Here, the switching arm 53 is shown in the basic position. The adjustment of the switching arm 53 from the basic position into the release position takes place by a pivoting movement about a pivot axis S, which in this example runs parallel to the vertical axis Z. The pivoting movement of the switching arm 53 takes place in each case relative to the winding arm 42 assigned to it. In the basic position, the switching arm 53 is spaced further from the winding arm 42 than in the release position.The holding device 6 has an electromagnet 61 which is provided to influence the restraining action. The electromagnet 61 is designed to apply an electromagnetic force to the switching arm 53 which at least contributes to the restraining effect. In the exemplary embodiment shown in FIG. 2, the restraining effect is even produced exclusively by the electromagnet 61. In detail, the electromagnetic force initiates a restraining torque with respect to the pivot axis S, which counteracts the pivoting from the basic position into the release position.The electromagnetic force of the electromagnet 61 can be variably adjusted. The adjustment is effected by controlling a current flowing through the electromagnet 61 by means of the actuating device 3.The adjusting device 3 is configured to adjust the electromagnetic force depending on a state of movement. In particular, it is configured to increase the electromagnetic force in a moved state in which the frame 11 of the bale wrapping device 1 has a relative speed with respect to a base 8, compared to a non-moved state in which the frame 11 does not have a relative speed with respect to the base 8. In the moved state, the current flow of the electromagnet 61 is increased for this purpose. In this case, it is ensured that the triggering energy for triggering the safety measure does not exceed a defined value in the non-moving state. In particular, it is ensured that the triggering energy does not exceed the above-mentioned value of 20 Joules. In the stationary state, the current flow in the electromagnet 61 is increased to a defined value, which is oriented in particular to the operating and / or ambient conditions.The state of movement can be detected sensorially in a manner known per se. Thus, a GPS sensor, an acceleration sensor and / or a rotational speed sensor for detecting the relative speed can be present on the bale wrapping device 1 and / or on the towing vehicle. The adjustment of the restraining effect is effected automatically as a function of the movement state detected by the sensor.The triggering of the safety measure likewise takes place automatically as soon as the switching arm 53 is pivoted into the triggering position. The switching unit 5 is assigned a sensor 51 which is provided for detecting the position of the switching arm 53. The sensor 51 detects the displacement of the switching arm 53 into the triggering position and sends a sensor signal to the actuating device 3. To detect the triggering position, the sensor 51 has an actuating means 54 (see FIGS. 4 and 5 ) which can be actuated by the pivoting movement of the switching arm into the triggering position. The actuating means 54 is designed here as a lever. The actuating device 3 processes the sensor signal and outputs a control command for carrying out the safety measure. The safety measure comprises at least the stopping of the bale wrapper arms 42. The safety measure optionally comprises further processes, such as, for example, the outputting of a warning signal to an operator of the bale wrapper 1 via an operator interface, the storing and / or sending of an accident log, the activation of the wrapping table 12 and / or a further device of the bale wrapper 1.The winding drive 7 has a hydraulic motor 71 which can be controlled via a valve block 74. The hydraulic motor 71 is supplied with energy via a hydraulic pressure which is provided by the towing vehicle via a supply line, not shown. The braking and / or stopping of the hydraulic motor 71 takes place via the control of the valve block 74 The valve block 74 is configured to process the control command of the actuating device 3 electronically. Alternatively, it can also be connected directly to the sensor 51 of the switching unit 5 in order to receive and process the sensor signal of the sensor 51 directly, i.e. independently of the actuating device 3.Furthermore, the winding drive 7 comprises a gear 72 which is drivingly connected to the hydraulic motor 71. A drive element 75 is coupled to the output of the transmission 72, which can be driven by the transmission 72 and on which the winding arms 42 and switching arms 53 are arranged. Each of the winding arms 42 is mounted in a fixed position on the drive element 75. The drive element 75 is therefore rigidly connected to each winding arm 42. Each of the switching arms 53 is in turn mounted on the drive element 75 such that it can rotate about the pivot axis S. Since the winding arm 42 is mounted in a fixed position on the drive element 75, the switching arm 53 is also rotatable relative to the winding arm 42. The winding axis W is defined by a drive axis of the drive element 75. The pivot axis S of the switching arm 53 is arranged in the first section of the switching arm 53 and extends parallel to the winding axis W in this example.The winding drive 7 also comprises a rotary feedthrough 73, The rotary feedthrough 73 has an electric slip ring in order to enable a power supply of the electromagnet 61 and a signal transmission at least between the actuating device 3, the valve block 74 and the sensor 51 of the switching unit 5. A rotation angle sensor (not shown) can also be integrated in the slip ring.As will be explained below with reference to the exemplary embodiments illustrated in FIGS. 3-5, the holding device 6 can have, in addition to the electromagnet 61, a force means 62, 63, 64, which is provided to influence the restraining effect. The force means 62, 63, 64 is designed to exert an additional force on the switching arm 53. The additional force contributes at least to the restraining effect of the holding device 6. The force means 62, 63, 64 acts independently of the electromagnet 61, and as a result, even when the electromagnet 61 is switched off, the switching arm 53 is held in the basic position by the force means 62, 63, 64, and the restraining effect is applied as a resistance to the pivoting into the release position.FIG. 3 shows a perspective partial view of a second embodiment of the bale wrapping device 1. the second embodiment differs from the first embodiment only in the holding device 6. The winding drive 7, the winding arms 42 and the switching arms 53 are only shown in a projection in this partial view.In this exemplary embodiment, the force means is designed as a spring 62. Specifically, the spring 62 is a tension spring. The spring 62 engages with a first end on the drive element 75 and with a second end on the switching arm 53. The spring 62 is designed to exert the additional force. The additional force corresponds in this embodiment to a restoring force of the spring 62, and the additional force contributes at least to the restraining effect, by which the switching arm 53 is held in the basic position and a resistance is applied to the pivoting from the basic position into the triggering position. If the above-mentioned triggering energy of 20 J is to be exactly maintained, the restoring force of the spring 62 can be adjustable in a manner not shown here, for example by setting a prestress.Fig. 4 shows a partial perspective view of a third embodiment of the bale wrapping device 1, which differs from the second embodiment in terms of the force means. Again, therefore, the remaining reference numerals will not be explained again.The force means is in this case designed as a magnet 63. The magnet 63 is provided in addition to the electromagnet 61. The magnet 63 is configured to exert the additional force that contributes at least to the restraining action. The additional force corresponds in this embodiment to a magnetic attractive force of the magnet 63. the magnet 63 can be designed as a permanent magnet or as an additional electromagnet.FIG. 5 shows a perspective partial view of a fourth embodiment of the bale wrapping device 1, which differs from the second embodiment also only in terms of the force means. The remaining reference numerals will not be explained again for this reason.In this embodiment, the force means is designed as a mechanical lock 64. The latch 64 includes a first latch 641 and a second latch 642. The first engaging member 641 is configured to receive and lock the second engaging member 642 by engaging. By the latching function, the switching arm 53 is held in the basic position by the mechanical lock 64.Unlocking is effected by pulling apart the latching elements 641, 642, at least one of the latching elements being elastically deformed. The latch 64 is configured to resist pulling apart by applying a latching force necessary for elastic deformation. The locking force contributes at least to the retaining effect. In this embodiment, the additional force of the force means corresponds to the locking force.Although only a single embodiment of the force means is always shown in FIGS. 3-5, a combination of spring 62, magnet 62 and / or locking mechanism 62 can be used as force means.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Cited Non-Patent LiteratureDIN EN ISO 4254-14:2016 [0002, 0081]
Claims
Bale-winding device (1) for winding a crop bale (2) with a winding material (41), wherein the bale-winding device (1) has a frame (11), at least one winding unit (4) which can be driven in rotation about a winding axis (W) in a rotational direction (R) relative to the frame (11) for discharging the winding material (41) to the crop bale (2), at least one switching unit (5) which leads the winding unit (4) in the rotational direction (R) and is provided for detecting an obstacle, and a holding device (6) which is configured to hold the switching unit (5) in a basic position, wherein the switching unit (5) can be deflected from the basic position into a release position by overcoming a restraining effect of the holding device (6) relative to the winding unit (4), whereby a safety measure of the bale wrapping device (1) can be triggered, characterized in that the holding device (6) comprises at least one electromagnet (61), which is designed to at least influence the restraining effect.Bale wrapping device (1) according to claim 1, characterized in that the electromagnet (61) is designed to generate an electromagnetic force acting on the switching unit (5) relative to the wrapping unit (4) which can be changed in order to at least influence the restraining effect.Bale wrapping apparatus (1) according to one of the preceding claims, characterized in that the holding device (6) comprises, in addition to at least one electromagnet (61), a force means (62, 63, 64) which is designed to generate an additional force acting on the switching unit (5) relative to the wrapping unit (4), wherein the additional force at least influences the restraining effect.Bale wrapping device (1) according to one of the preceding claims, characterized in that the additional force is oriented at least partially in a force direction of the electromagnetic force of the electromagnet (61) or acting against the force direction.Bale wrapping device (1) according to one of the preceding claims, characterized in that the influence of the force means (62, 63, 64) on the restraining effect is independent of the influence of the electromagnet (61).Bale wrapping device (1) according to one of the preceding claims, characterized in that the influence of the force means (62, 63, 64) on the restraining effect is independent of an operating state of the bale wrapping device (1), and / or the force means (62, 63, 64) is designed as a passive force means (62, 63, 64).Bale wrapping device according to one of the preceding claims, characterized in that the force means (62, 63, 64) has at least one spring (62), a magnet (63) and / or a mechanical locking mechanism (64).Bale wrapping apparatus (1) according to the preamble of claim 1 or according to one of the preceding claims, characterized in that the bale wrapping apparatus (1) comprises an adjusting device (3) which is configured to automatically adjust the restraining effect depending on a state of movement of the frame (11) relative to a base (8).Bale wrapping device (1) according to one of the preceding claims, characterized in that the restraining effect is increased in a moved state of the frame (11) compared to an unmoved state of the frame (11).Bale wrapping device (1) according to one of the preceding claims, characterized in that the restraining effect can be adjusted independently of the basic position of the switching unit (5) and / or with the basic position of the switching unit (5) remaining the same.Bale wrapping device (1) according to one of the preceding claims, characterized in that the switching unit (5) has a switching arm (53) which can be pivoted about a pivot axis (S) between the basic position and the release position.Bale wrapping device (1) according to one of the preceding claims, characterized in that a restraining moment about the pivot axis (S) is introduced by the electromagnetic force and / or the additional force, wherein the restraining moment acts in the opposite direction to the pivoting of the switching arm (53) from the basic position into the release position.Bale wrapping device (1) according to one of the preceding claims, characterized in that the bale wrapping device (1) comprises a sensor (51), which is provided to detect a position of the switching arm (53) relative to the wrapping arm (42), wherein the safety measure can be triggered depending on the detected position.Bale wrapping device (1) according to one of the preceding claims, characterized in that the safety measure is provided at least to at least brake the wrapping unit (4).Method for operating a bale wrapping device (1) for wrapping a crop bale (2) with a wrapping material (41), wherein the bale wrapping device (1) comprises a frame (11), at least one wrapping unit (4) that can be driven in rotation about a wrapping axis (W) in a rotational direction (R) relative to the frame (11) for delivering the wrapping material (41) to the crop bale (2), at least one switching unit (5) that leads the wrapping unit (4) in the rotational direction (R) and is provided for detecting an obstacle, and a holding device (6) that is configured to hold the switching unit (5) in a basic position, wherein the switching unit (5) can be deflected from the basic position into a triggering position by overcoming a restraining effect of the holding device (6) relative to the wrapping unit (4), whereby a safety measure of the bale wrapping device (1) can be triggered, characterized in that the restraining effect is automatically adjusted depending on a state of movement of the frame (11) relative to a base (8).