FORT WINCH

Description

[0001] The invention relates to a forestry winch comprising a cable drum driven by a drive motor, on which a cable is wound, wherein the cable drum is operatively connected to a braking device, wherein the braking device is designed as a spring-applied brake, which is acted upon by a spring device in the direction of a braking position and by a hydraulic brake release pressure present in a brake release pressure line in the direction of a release position, wherein the drive motor is designed as a hydraulic motor, which is connected by means of a first pressure medium line and a second pressure medium line to a control directional control valve device controlling the drive motor, wherein a bypass valve device connecting the pressure medium lines is provided, which is arranged in a connecting line connecting the two pressure medium lines and which has a closed position and a flow position.wherein the bypass valve device is actuated by a hydraulic control pressure present in a control line in the direction of the closed position, wherein the spring-applied brake and the bypass valve device are jointly actuated by a control valve, wherein the control valve controls the control pressure actuating the bypass valve device in the direction of the closed position and the brake release pressure actuating the spring-applied brake in the direction of the release position, such that when the spring-applied brake is actuated in the release position, the bypass valve device is actuated in the closed position, and when the spring-applied brake is actuated in the brake position, the bypass valve device is actuated in the flow position.wherein in a first control position of the control valve the spring-applied brake is in the braking position and the bypass valve device is in the flow position, and in a second control position of the control valve the spring-applied brake is in the release position and the bypass valve device is in the blocking position.

[0002] From DE 10 2018 104 810 A1 a mobile forestry machine with a forestry winch is known, which is designed as a hydraulic motor, which is connected to a control directional control valve device that controls the drive motor by means of a first pressure medium line and a second pressure medium line.

[0003] It is also known to equip forestry winches with a braking device designed as a spring-applied brake, with which the cable drum is braked with a defined braking torque.

[0004] If a forestry winch equipped with a spring-applied brake is driven by a hydraulic motor, operating conditions can occur in which the cable drum is braked by a hydraulic braking torque in addition to the mechanical braking torque of the spring-applied brake. This can happen, for example, when the control directional control valve is in a locked position, in which both hydraulic lines are closed. If a tensile force is applied to the cable while the control directional control valve is in the locked position, for example, by a falling tree, braking pressure builds up in the closed hydraulic lines, which slows the cable drum. The sum of the braking torque of the spring-applied brake and the hydraulic braking torque can result in such a high total braking torque that a machine equipped with the forestry winch can no longer absorb the total braking torque and is damaged or destroyed.

[0005] From FR 2 547 569 A1 a hydraulic control device for a hydraulic motor is known, which drives a chain winch on board fishing boats.

[0006] US Patent 3,976,333 A discloses a winch with the features of the preamble of claim 1.

[0007] The present invention is based on the objective of providing a generic forestry winch that avoids the aforementioned disadvantages and enables safe operation.

[0008] This problem is solved according to the invention by first actuating the bypass valve device into the blocking position when the control valve is actuated into the second control position and then acting the spring brake into the release position.

[0009] The bypass valve creates a short circuit between the two hydraulic lines in the flow position. This prevents the build-up of hydraulic brake pressure that would otherwise slow the cable drum when the control valve is in the closed position (where both hydraulic lines are shut off). With such a bypass valve, it is ensured that the cable drum is only braked by the mechanical braking torque of the spring-applied brake in the flow position. This safely and easily protects a forestry winch-equipped machine from overload caused by excessive braking torque on the cable drum.A high level of functional and operational reliability can be easily achieved by using a control valve that controls the control pressure actuating the bypass valve device and the brake release pressure actuating the spring brake, thus jointly controlling the spring brake and the bypass valve device. This ensures that when the spring brake is actuated into the release position, the bypass valve device is in the closed position, and when the spring brake is actuated into the braking position, the bypass valve device is in the flow position.

[0010] According to the invention, in a first control position of the control valve, the spring-applied brake is in the braking position and the bypass valve assembly is in the flow position, and in a second control position of the control valve, the spring-applied brake is in the release position and the bypass valve assembly is in the closed position. This enables a high degree of functional and operational reliability in a simple manner, since in the first control position of the control valve the spring-applied brake is in the braking position and the bypass valve assembly is in the flow position, and in a second control position the spring-applied brake is in the release position and the bypass valve assembly is in the closed position.Unsafe operating conditions, such as a bypass valve device in the flow position with the spring brake applied in the release position, in which the cable drum can rotate uncontrollably when a force is applied to the cable, are thus safely avoided.

[0011] According to the invention, when the control valve is actuated to the second control position, the bypass valve assembly is actuated to the closed position first, followed immediately by the spring-applied brake being actuated to the release position. This ensures that, in the second control position, the bypass valve assembly is actuated to the closed position before the spring-applied brake is actuated to the release position. This further increases functional and operational reliability, as unsafe operating conditions, such as the bypass valve assembly still being in the flow position when the spring-applied brake is already actuated to the release position, in which the cable drum can rotate uncontrollably under force applied to the cable, are safely and easily avoided.

[0012] According to an advantageous embodiment of the invention, the bypass valve assembly is actuated by the control pressure present in the control line in the direction of the closed position. This enables a high level of functional and operational reliability, since in the absence of control pressure and brake release pressure, it is ensured that the spring-applied brake is actuated into the braking position by its spring mechanism and that the bypass valve assembly is actuated into the flow position, for example by a spring mechanism, and thus the cable drum is only braked by the mechanical braking torque of the spring-applied brake.

[0013] According to an advantageous embodiment of the invention, the bypass valve assembly is designed as a bypass valve directly actuated by the control valve, wherein in the first control position the control valve connects the brake release pressure line and the control line to a reservoir, and in the second control position connects the brake release pressure line and the control line to a control pressure source. The bypass valve is thus directly actuated and controlled by the control pressure generated by the control valve. If the control valve connects the brake release pressure line and the control line to a reservoir in the first control position, it is easily achieved and ensured that the spring-applied brake is in the braking position and the bypass valve assembly is in the flow position.If the control valve in the second control position connects the brake release pressure line and the control line to a control pressure source, it is easily achieved and ensured that the spring-applied brake is in the release position and the bypass valve device is in the locking position.

[0014] According to an alternative and equally advantageous embodiment of the invention, the bypass valve assembly is designed as a pilot-operated bypass valve controlled by the control valve, wherein the control valve actuates a pilot valve which, in the first switching position, connects the control line to a reservoir and, in the second control position, connects the control line to a control pressure source. In a first control position, the control valve connects the brake release pressure line and a pilot line leading to the pilot valve to a reservoir, and in a second control position, it connects the brake release pressure line and the pilot line to a control pressure source. The bypass valve is thus pilot-operated by the control pressure generated by the control valve, and the control pressure generated by the control valve actuates the pilot valve, which in turn actuates the bypass valve assembly.With such a pre-control of the bypass valve device, a reliable actuation of the bypass valve device into the closed position can be achieved, especially in the case of a bypass valve with a large nominal diameter.

[0015] Advantageously, the pilot valve is actuated by a spring in the direction of the first control position and by the pilot pressure present in the pilot line in the direction of the second control position. When the control valve is in the second control position, the spring-applied brake is thus actuated into the release position, and the pilot valve is actuated into the second control position by the pilot pressure present in the pilot line. In this second position, the connection of the control line of the bypass valve assembly to the control pressure source actuates the bypass valve assembly into the closed position. This simply achieves and ensures that the spring-applied brake is in the release position and the bypass valve assembly is in the closed position.With the control valve in the first control position, the spring-applied brake is actuated into the braking position and the pilot valve is actuated into the first control position by the relief of the pilot line from the spring, in which the bypass valve device is actuated into the flow position by the relief of the control line to the reservoir, thus achieving and ensuring in a simple way that the spring-applied brake is in the braking position and the bypass valve device is in the flow position.

[0016] According to a further development of the invention, the control line is connected to the control pressure source and the first pressure medium line by means of a changeover valve. The changeover valve selects either the control pressure present in the control line or the high pressure present in the first pressure medium line to actuate the bypass valve assembly into the closed position. If, upon appropriate actuation of the control directional control valve assembly, the drive motor of the cable drum is driven by a high pressure present in the first pressure medium line, the high pressure can be easily selected to actuate the bypass valve assembly by means of the changeover valve assembly, thus reliably holding the bypass valve assembly in the closed position when the cable drum drive motor is driven.

[0017] According to an advantageous embodiment of the invention, a freewheel valve is arranged in the control line. In a first control position, this valve opens the control line, and in a second control position, it relieves pressure on a section of the control line connected to the bypass valve assembly leading to a container. Thus, in its second control position, the freewheel valve, by relieving pressure on the section of the control line connected to the bypass valve leading to the container, allows the bypass valve assembly to be actuated into the flow position, for example, by a spring. With the spring-applied brake in the released position, the bypass valve assembly can therefore be easily actuated into the flow position by actuating the freewheel valve in the second control position. This makes it easy to rotate the cable drum by applying a tensile force to the cable when the spring-applied brake is in the released position.This allows, for example, the cable of a work machine equipped with a forestry winch to be attached to a tree, and, with the control directional control valve not activated, the cable to be unwound from the cable drum while the work machine is moving.

[0018] The freewheel valve is advantageously actuated by a spring in the direction of the first control position and by an electrical actuator, in particular a solenoid, in the direction of the second control position. This ensures a high level of safety, since when the actuator is not engaged, the freewheel valve is in the first control position, which opens the control line of the bypass valve assembly, and in this position the functions of the bypass valve assembly and the spring-applied brake assembly are controlled by the control valve.

[0019] According to an advantageous embodiment of the invention, the control valve can be actuated by a spring in the direction of the first control position and by an electrical actuating device, in particular a switching solenoid, in the direction of the second control position. This further increases functional and operational reliability, since the control valve is in the first control position when the actuating device is not engaged, in which the spring-applied brake is in the braking position and the bypass valve is in the flow position. The control valve can be easily actuated into the second control position using an electrical actuating device.

[0020] According to an advantageous embodiment of the invention, the control directional control valve assembly is actuated by hydraulic actuation pressures, wherein the control valve can be actuated by a spring in the direction of the first control position and by the hydraulic actuation pressures of the control directional control valve assembly in the direction of the second control position. This further increases functional and operational reliability, since, in the absence of actuation pressures from the control directional control valve assembly, the control valve is in the first control position, in which the spring-applied brake is in the braking position and the bypass valve assembly is in the flow position. Using the hydraulic actuation pressures of the control directional control valve assembly to actuate the control valve in the second control position enables simple actuation of the control valve without an additional electrical actuation device.

[0021] According to an advantageous embodiment, the spring assembly of the spring-applied brake and a spring assembly of the bypass valve assembly acting in the direction of the flow position, or the spring assembly of the pilot valve, are designed such that when the control valve is actuated to the second control position, the bypass valve assembly is actuated to the closed position first, and subsequently the spring-applied brake is actuated to the release position. By designing the preload of the respective spring assemblies, it can be easily ensured that, when the control valve is actuated to the second control position, the bypass valve assembly is actuated to the closed position before the spring-applied brake is actuated to the release position.

[0022] According to an alternative and equally advantageous embodiment, a spring-loaded check valve, in particular a non-return valve, opening towards the spring-applied brake, is arranged in the brake release pressure line. With such a spring-loaded check valve in the brake release pressure line of the spring-applied brake, the timing of the bypass valve's actuation into the locked position before the spring-applied brake's actuation into the release position can also be easily ensured when the control valve is actuated to the second control position.

[0023] A particular advantage here is the arrangement of an unpreloaded check valve, especially a non-preloaded check valve, in a bypass line that bypasses the spring-loaded check valve. This bypass line allows the brake release pressure in the brake release pressure line to dissipate quickly to the reservoir via the open, unpreloaded check valve, so that the spring-loaded check valve does not impede the engagement of the spring-applied brake.

[0024] According to a further development of the invention, a spring-loaded shut-off valve, in particular a check valve, opening towards the first pressure medium line, is arranged in a line connecting the first pressure medium line to the second pressure medium line. With such a spring-loaded shut-off valve opening from the second to the first pressure medium line, a back pressure can be generated from the second to the first pressure medium line. The shut-off valve makes it possible, for example, for the cable drum to be rotated by a tensile force applied to the cable when the spring-applied brake is in the release position. This makes it possible, for example, with a forestry winch-equipped machine, to attach the cable to a tree and, with the control directional control valve not activated, to unwind the cable from the cable drum while the machine is moving.

[0025] According to a further development of the invention, the forestry winch is equipped with an ejector roller for the rope driven by a further drive motor, wherein the further drive motor is designed as a hydraulic motor which is connected by means of a first connecting line and a second connecting line to a control directional control valve device that controls the further drive motor. With an ejector roller driven by the further drive motor, a desired rope tension can be applied to the rope when unwinding the rope from the rope drum as well as when winding the rope onto the rope drum, which enables safe and orderly unwinding of the rope from the rope drum and safe and orderly winding of the rope onto the rope drum during hoisting.The rope tension applied to the rope by the driven ejector roller allows for low operating forces to be achieved for an operator who has to pull the rope over a considerable distance of up to 100m when unwinding the rope from the rope drum.

[0026] According to an advantageous embodiment of the invention, a non-preloaded shut-off valve, in particular a check valve, opening towards the first pressure medium line, is arranged in a connecting line linking the first pressure medium line to the second pressure medium line. A valve controlled by the pressure in the first connecting line is arranged in the connecting line and has a closed position and a flow position. The pressure from the second to the first pressure medium line can be switched between a low pressure of the non-preloaded shut-off valve and a higher pressure of the spring-loaded shut-off valve by means of the valve controlled by the valve in the first connecting line.If the pressure in the first connecting line increases, the system can switch to the higher dynamic pressure, so that, with appropriate control of the directional control valve, the cable drum is driven by the drive motor in such a way that the ejector roller driven by the other drive motor is supported by the cable drum driven in the unwinding direction when the cable is unwound.

[0027] The valve is advantageously actuated by a spring in the direction of the flow position and by the pressure in the first connecting line in the direction of the closed position. If the pressure in the first connecting line increases, and thus the drive motor of the ejector roller requires high pressure to unwind the rope from the cable drum, actuating the shut-off valve to the closed position automatically switches to the higher back pressure of the spring-loaded shut-off valve, so that the drive motor of the cable drum also operates in the unwinding direction of the rope and assists the ejector roller in unwinding the rope from the cable drum.

[0028] The invention further relates to a mobile work machine, in particular a remote-controlled mobile work machine without a driver's workstation, with a forestry winch according to the invention. Remote-controlled mobile work machines without a driver's workstation have a compact and lightweight design. With a bypass valve device according to the invention, which ensures that the cable drum is only braked by the mechanical braking torque of the spring-applied brake, a lightweight and compact remote-controlled work machine can be protected safely and easily from overload caused by excessive braking torque at the cable drum.

[0029] Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiments shown in the schematic figures. Here, it is shown that Figure 1 shows a schematic representation of a forestry winch according to the invention, Figure 2 shows a first embodiment of a hydraulic circuit diagram of a forestry winch according to the invention, Figure 3 shows a second embodiment of a hydraulic circuit diagram of a forestry winch according to the invention, Figure 4 shows a further development of the Figures 2 and 3 Figure 5, a further development of Figures 2 to 4 Figure 6, a further development of Figures 2 to 5 and Figure 7 a third embodiment of a hydraulic circuit diagram of a forestry winch according to the invention,

[0030] In the Figure 1 A forestry winch 1 according to the invention is shown in a schematic representation. The left-hand representation of the Figure 1 Figure 1 shows a perspective view and the right-hand view shows a front view of the forestry winch according to the invention 1.

[0031] The forestry winch 1 has a cable drum 3 driven by a drive motor 2, on which a cable 4, for example a steel cable, is wound. The cable drum 3 is rotatably mounted about a pivot axis 5 and is driven by the drive motor 2, which is a hydraulic motor.

[0032] In the illustrated embodiment, the forestry winch 1 further comprises an ejector roller 7 for the cable 4, driven by a further drive motor 6. The ejector roller 7 is rotatably arranged about a pivot axis 8 and is driven by the drive motor 6, which is designed as a hydraulic motor.

[0033] In the illustrated embodiment, the rope 4 is guided from the rope drum 3 in a vertical direction V to the ejector roller 7, guided over the ejector roller 7 and deflected at the ejector roller 7 in such a way that the rope 4 is guided away from the ejector roller 7 in a horizontal direction H.

[0034] Rope 4 is connected by means of a - in the Figure 1 For the sake of clarity, the pressure device is not shown in detail and is pressed onto the ejector roller 7.

[0035] The rope drum 3 or the drive motor 2 remains in operative connection with a braking device 9.

[0036] In the Figures 2 to 7 Hydraulic circuit diagrams of the forestry winch 1 according to the invention are shown, wherein identical components are provided with the same reference numerals.

[0037] In the Figure 2The drive motor 2 of the cable drum, designed as a hydraulic motor, can be controlled by means of a control directional control valve 10. The control directional control valve 10 is connected to a delivery line 11 of a hydraulic pump 12, which draws hydraulic fluid from a reservoir 13, to a tank line 14 leading to the reservoir 13, and to a first hydraulic fluid line 15 connected to a port R of the drive motor 2, as well as to a second hydraulic fluid line 16 connected to a port L of the drive motor 2. A pressure relief valve 17, which safeguards against a maximum working pressure in the hydraulic fluid line 15, is connected to the first hydraulic fluid line 15. Similarly, a pressure relief valve 18, which safeguards against a maximum working pressure in the hydraulic fluid line 16, is connected to the second hydraulic fluid line 16.

[0038] The control directional control valve assembly 10 has a neutral position 10a in which the delivery line 11, the tank line 14, and the pressure medium lines 15 and 16 are closed. The control directional control valve assembly 10 has a first control position 10b in which the delivery line 11 is connected to the first pressure medium line 15, and the second pressure medium line 16 is connected to the tank line 14. In the first control position 10b, the drive motor 2 operates in the winding direction, in which the rope is wound onto the rope drum. The control directional control valve assembly 10 has a second control position 10c in which the delivery line 11 is connected to the second pressure medium line 16, and the first pressure medium line 15 is connected to the tank line 14. In the second control position 10c, the drive motor 2 operates in the unwinding direction, in which the rope is unwound from the rope drum.

[0039] The additional drive motor 6 of the ejector roller, designed as a hydraulic motor, can be controlled by means of a further control directional control valve 20. The control directional control valve 20 is connected to a delivery line 21 of another hydraulic pump 22, which draws hydraulic fluid from the reservoir 13, to a tank line 24 leading to the reservoir 13, and to a first connection line 25 connected to a first connection of the drive motor 6, as well as to a second connection line 26 connected to a second connection of the drive motor 6. A pressure relief valve 27, which protects against a maximum working pressure in the connection line 25, is connected to the first connection line 25. Similarly, a pressure relief valve 28, which protects against a maximum working pressure in the connection line 26, is connected to the second connection line 26.It is understood that, as an alternative to supplying both drive motors 2, 6, only one hydraulic pump 12 or 23 can be provided.

[0040] The control directional control valve assembly 20 has a closed position 20a in which the delivery line 21, the tank line 24, and the connecting lines 25 and 26 are closed. The control directional control valve assembly 20 has a first control position 20b in which the delivery line 21 is connected to the first connecting line 25, and the second connecting line 26 is connected to the tank line 24. In the first control position 20b, the drive motor 6 is operated in the unwinding direction, in which the rope is unwound from the rope drum. The control directional control valve assembly 20 has a second control position 20c in which the delivery line 21 is connected to the second connecting line 26, and the first connecting line 25 is connected to the tank line 24.

[0041] The control directional valves 10, 20 can be controlled to the control positions 10b, 10c, 20b, 20c by means of an electronic control unit 30.

[0042] The braking device 9, which is operatively connected to the rope drum 3 or the drive motor 2, is designed as a spring-applied brake, which is acted upon by a spring device 35 in the direction of a braking position and by a hydraulic brake release pressure in a brake release pressure line 36 in the direction of a release position.

[0043] A spring-loaded shut-off valve 41, opening towards the first pressure medium line 15, can be arranged in a line 40 connecting the first pressure medium line 15 with the second pressure medium line 16. In the illustrated embodiment, the shut-off valve 41 is designed as a check valve, which is held in a closed position by a spring.

[0044] According to the invention, a bypass valve device 45 connecting the two pressure medium lines 15, 16 is provided, which is arranged in a connecting line 46 connecting the two pressure medium lines 15, 16. The bypass valve device 45 is, in the illustrated embodiment, the Figure 2 designed as a switching valve, which has a blocking position 45a and a flow position 45b.

[0045] The bypass valve assembly 45 is actuated by a hydraulic control pressure present in a control line 50 in the direction of the closed position 45a. The bypass valve assembly 45 is actuated by a spring assembly 47 in the direction of the flow position 45b.

[0046] The spring-applied brake 9 and the bypass valve assembly 45 are jointly controlled by a control valve 55.

[0047] In the Figure 2The bypass valve assembly 45 is designed as a bypass valve directly controlled by the control valve 55. For this purpose, the control valve 55 is designed as a three-port, two-position valve, which is connected at a first port to the control line 55 and the brake release pressure line 36, at a second port to a control pressure source 56, and at a third port to a tank line 57 leading to the reservoir 13. In the illustrated embodiment, the control pressure source 56 is designed as a feed pump 58, which draws pressure medium from the reservoir 13 and delivers it to a delivery line 59 connected to the second port of the control valve 55.

[0048] The control valve 55 has a first control position 55a, in which the brake release pressure line 36 and the control line 50 are connected to the reservoir 13, and a second control position 55b, in which the brake release pressure line 36 and the control line 50 are connected to the delivery line 59 of the feed pump 58 and thus to the control pressure source 56. In the first control position 55a, the delivery line 59 remains closed. In the second control position 55b, the tank line 57 remains closed.

[0049] In the first control position 55a, the control valve 55 relieves the brake release pressure line 36 and the control line 50 to the reservoir 13, so that in the first control position 55, the spring-applied brake 9 is actuated by the spring assembly 35 into the braking position, and the bypass valve assembly 45 is actuated by the spring assembly 47 into the flow position 45b. In the second control position 55b, the control valve 55 connects the brake release pressure line 36 and the control line 50 to the delivery line 59 of the feed pump 58, so that in the second control position 55b, the spring-applied brake 9 is actuated by the delivery pressure provided by the feed pump 58 against the force of the spring assembly 35 into the release position, and the bypass valve assembly 45 is actuated by the delivery pressure provided by the feed pump 58 against the force of the spring assembly 47 into the closed position 45a.

[0050] The control valve 55 can be actuated by a spring 60 in the direction of the first control position 55a and by an electrical actuator 61, for example a solenoid, in the direction of the second control position 55b. The actuator 61 is connected to the electronic control unit 30 for control purposes.

[0051] A free-running valve 65 is arranged in the control line 50, which in a first control position 65a opens the control line 50 and in a second control position 65b relieves a section of the control line 50 connected to the bypass valve device 45 to the container 13.

[0052] The free-running valve 65 can be actuated by a spring 66 in the direction of the first control position 65a and by an electrical actuating device 67, for example a switching solenoid, in the direction of the second control position 65b. The actuating device 67 is connected to the electronic control unit 30 for control purposes.

[0053] To brake the cable drum using the spring-applied brake device 9, for example, when the control directional control valve 10 is not actuated and is in the neutral position 10a, the control valve 55 and the freewheel valve 65 are not actuated, so that the control valve 55 is in the first control position 55a and the freewheel valve 65 is in control position 65a. By relieving the brake release pressure line 36 and the control line 50 to the reservoir 13 in the first control position 55a of the control valve 55, the spring-applied brake 9 is actuated by the spring device 35 into the braking position, and the bypass valve 45 is actuated by the spring device 47 into the flow position 45b. The bypass valve 45, in the flow position 45b, ensures that the drive motor 2 or the cable drum is braked only by the mechanical braking torque of the spring-applied brake 9.

[0054] To release the spring-applied brake device 9 of the cable drum, for example when the control directional control valve device 10 for driving the drive motor 2 is actuated by the control device 30 to the control position 10b or 10c, the control device 30 actuates the actuating device 61, so that the control valve 55 is actuated to the second control position 55b, in which the brake release pressure line 36 and the control line 50 are connected to the delivery line 59 of the feed pump 58, so that the spring-applied brake 9 is actuated into the release position by the delivery pressure provided by the feed pump 58 against the force of the spring device 35 and the bypass valve device 45 is actuated into the closed position 45a by the delivery pressure provided by the feed pump 58 against the force of the spring device 47.The control of the control directional control valve assembly 10 and the control valve 55 is preferably carried out such that the spring-applied brake 9 is actuated into the release position and the bypass valve assembly 45 into the locking position 45a, before the control directional control valve assembly 10 connects the delivery line 11 with the pressure medium line 15 or 16 in the control position 10b or 10b.

[0055] If, with the spring-applied brake 9 in the release position and the control directional control valve 10 in the locked position 10a, it is necessary to allow the rope to be unwound from the rope drum, the control device 30, by actuating the actuating device 67, controls the freewheel valve 65 to the second control position 65b, in which the section of the control line 55 connected to the bypass valve 50 is relieved of pressure and thus the bypass valve 45 is actuated by the spring device 47 into the flow position 45b. With the spring-applied brake 9 in the release position and the bypass valve 45 in the flow position 45b, the rope drum can therefore be rotated and the rope unwound from the rope drum by applying a tensile force to the rope.This makes it possible, for example, in the case of a work machine equipped with a forestry winch, to attach the rope to a tree and, with the control directional control valve device 10 not activated, to unwind the rope from the rope drum by means of the hydraulic short circuit of the drive motor 2 produced in the flow position 45b of the bypass valve 45 while the work machine is moving.

[0056] The optionally present check valve 41 makes it possible to drive the drive motor 2 of the rope drum in the second control position 10c of the control directional control valve assembly 10 with a pressure in the unwinding direction limited by the preload of the spring of the check valve 41.

[0057] The control valve 55 is used to release the spring-applied brake device 9 in the second control position 55b by means of a signal (delivery pressure of the feed pump 58) at the first connection, to which the control line 55 and the brake release pressure line 36 are connected. This actuates the spring-applied brake device 9 into the release position and the bypass valve 45 into the locking position 45a. For high functional and operational reliability, it is designed that when the control valve 55 is actuated into the second control position 55b, the bypass valve 45 is actuated into the locking position 45a first, and subsequently the spring-applied brake 9 is actuated into the release position.

[0058] In the Figure 2For this temporal actuation of the bypass valve assembly 45 into the closed position 45a before the spring-applied brake 9 is actuated into the release position 13, the spring assembly 35 of the spring-applied brake 9 and the spring assembly 47 of the bypass valve assembly 45 are designed accordingly. Preferably, the preload of the spring assembly 47 of the bypass valve assembly 45 is selected to be lower than the preload of the spring assembly 35 of the spring-applied brake 9, for example, the preload of the spring assembly 47 of the bypass valve assembly 45 is set to approximately 2 bar and the preload of the spring assembly 35 of the spring-applied brake 9 to approximately 10 bar.set to 10 bar, so that when the brake release pressure line 36 and the control line 50 are connected to the delivery line 59 in the second control position 55b of the control valve 55, the bypass valve 45 is actuated into the closed position 45a before the spring brake device 9 is actuated into the release position against the preload of the spring device 35.

[0059] In the Figure 3 is a variant of Figure 2 shown, in which the temporal actuation of the bypass valve device 45 into the locking position 45a before the application of the spring-applied brake 9 into the release position 13 is implemented in an alternative manner.

[0060] In the Figure 3For this purpose, a spring-loaded shut-off valve 70, for example a check valve, opening towards the spring-applied brake 9, is arranged in the brake release pressure line 35. The spring-loaded shut-off valve 70 is preloaded such that, in the second control position 55b of the control valve 55, it is ensured that the bypass valve device 45 is actuated to the closed position 45a before the spring-applied brake 9 is actuated to the release position 13.

[0061] In a bypass line 71 bypassing the spring-loaded shut-off valve 70, an unloaded shut-off valve 72, for example a check valve, is arranged, opening towards the control valve 55. The shut-off valve 72 allows the brake release pressure present in the brake release pressure line 36 to be quickly reduced to the reservoir 13 via the opening shut-off valve 72 in the first control position 55a of the control valve 55.

[0062] The Figure 4shows a variant of the Figures 2 and 3 , in which the bypass valve 45 can additionally be actuated into the closed position 45a by the pressure present in the first pressure medium line 15.

[0063] For this purpose, the control line 50 is connected to the control pressure source 56 and the first pressure medium line 15 by means of a changeover valve 90. The changeover valve 90 is connected at one outlet to the section of the control line 50 leading to the bypass valve 45, at one first inlet to the section of the control line 50 connected to the control pressure source 56 via the free-running valve 65 and the control valve 55, and at another inlet to the first pressure medium line 15.

[0064] Provided that a corresponding pressure is present in the first pressure medium line 15, for example when the control directional control valve 10 is actuated to the first control position 10b, the bypass valve 45 is actuated and held in the closed position 45a by the pressure present in the first pressure medium line 15. This ensures that the bypass valve 45 closes reliably.

[0065] In the Figure 4 In the neutral position 10a of the control directional control valve assembly 10, the pressure medium lines 15, 16 to the container 13 are relieved of pressure. This allows the pressure medium line 15 to be relieved of pressure in the neutral position 10a of the control directional control valve assembly 10, so that the bypass valve 45 can be actuated by the spring assembly 47 into the flow position 45b.

[0066] In the Figures 2 to 4 The control valve 55 is electrically actuated by the electrical actuator 61. Figure 5 shows a variant of the Figures 2 to 4, in which the control valve 55 can be actuated into the second control position 55b without additional electrical actuating device 61.

[0067] In the Figure 5 The control directional control valve assembly 10 is electro-hydraulically actuated, whereby electrically actuated pilot valves 80a, 80b generate hydraulic actuation pressures that actuate the control directional control valve assembly 10 to the control positions 10b and 10c, respectively. The control valve 55 is in the Figure 4The control valve 55 can be actuated by spring 60 in the direction of the first control position 55a and by the hydraulic actuation pressures of the control directional control valve assembly 10 in the direction of the second control position 55b. A corresponding control surface of the control valve 55 is connected to a control pressure line 85, which selects the appropriate actuation pressure of the control directional control valve assembly 10 for actuating the control valve 55 via a changeover valve 86. The control directional control valve assembly 10 is further biased and centered in the neutral position 10a by springs 87a and 87b. Figure 5The preloads of springs 87a, 87b are higher than the preload of spring 60 of control valve 55. If one of the pilot valves 80a, 80b is actuated, the actuating pressure generated by the pilot valve 80a or 80b actuates the control valve 55 to the second control position 55b before the control directional control valve 10 moves to control position 10b or 10c, so that the spring-applied brake 9 is actuated to the release position and the bypass valve 45 to the closed position 45a, before the control directional control valve 10, in control position 10b or 10c, connects the delivery line 11 to the pressure medium line 15 or 16.

[0068] In the Figure 6 is a variant of Figures 2 to 5shown, in which a non-preloaded shut-off valve 101, for example a check valve, is arranged in a connecting line 100 connecting the first pressure medium line 15 with the second pressure medium line 16.

[0069] A valve 102, controlled by the pressure in the first connecting line 25, is also arranged in the connecting line 100. The valve 102 has a closed position 102a and a flow position 102b. A spring 103 actuates the valve 102 in the direction of the flow position 102b, and the pressure in the first connecting line 25 actuates it in the direction of the closed position 102a.

[0070] In the Figure 6Thus, two shut-off valves 41 and 101 are provided, connecting the second pressure medium line 16 to the first pressure medium line 15, with the spring-loaded shut-off valve 41 generating a higher back pressure from the second pressure medium line 16 to the first pressure medium line 15 than the unloaded shut-off valve 101. The back pressure from the second pressure medium line 16 to the first pressure medium line 15 can be switched between the low pressure of shut-off valve 101 and the increased pressure of shut-off valve 41 by means of valve 102, which is controlled by the pressure and thus the load of the drive motor 6 of the ejector roller.

[0071] The Figure 6 It enables the unwinding of the rope from the rope drum by the drive motor 6 of the ejector roller to be supported by the drive motor 2 depending on the load of the drive motor 6.

[0072] To unwind the rope from the rope drum, the control directional control valve 10 is actuated in the direction of the second control position 10c and the control directional control valve 20 is actuated in the direction of the control position 20b.

[0073] In control position 20b, the drive motor 6 of the ejector roller is driven in the unwinding direction by the flow of volume in the first connecting line 25, which is connected to the delivery line 21 of the hydraulic pump 22. If the pressure in the first connecting line 25 is sufficient to drive the drive motor 6 of the ejector roller, and this pressure is less than the preload of the spring 103 of the valve 102, which is, for example, 100 bar, the valve 102 is acted upon by the spring 103 in the flow position 102b.The flow of fluid entering the pressure medium line 16, which in control position 10c of the control directional control valve 10 is connected to the delivery line 11 of the hydraulic pump 12, can thus flow through the opening shut-off valve 101 at low back pressure into the pressure medium line 15, which in control position 10c of the control directional control valve 10 is connected to the reservoir 13, so that the drive motor 2 of the cable drum can rotate freely and the cable is unwound from the cable drum by means of the ejector roller driven by the drive motor 6. If the load on the drive motor 6 of the ejector roller increases and the drive motor 6 of the ejector roller requires a pressure in the first connecting line 25 for operation that is higher than the preload of the spring 103 of the valve 102, the valve 102 is acted upon by the pressure present in the first connecting line 25 in the closed position 102a.The shut-off valve 101 switches to the shut-off valve 41, which is set to a higher back pressure. This causes the drive motor 2 of the cable drum to be driven in the unwinding direction with the back pressure set at the shut-off valve 41. The cable drum driven by the drive motor 2 thus assists the drive motor 6 of the ejector roller in unwinding the cable from the cable drum.

[0074] In the Figures 2 to 6 The bypass valve device 45 is designed as a bypass valve directly controlled by the control valve 55.

[0075] The Figure 7 shows a variant of the Figures 2 to 7 with a bypass valve device 45, which is designed as a pilot-operated bypass valve 45.

[0076] The bypass valve 45 of the Figure 7 It is designed as a poppet valve. The poppet valve has a locking piston 110 which actuates a valve seat in the connecting line 46.

[0077] The locking piston 110 has a first control surface 110a, which acts in the direction of a flow position and is subjected to the pressure in the first pressure medium line 15; a second control surface 110b, which acts in the direction of a flow position and is subjected to the pressure in the second pressure medium line 16; and a third control surface 110c, which acts in the direction of a blocking position and is subjected to the pressure in the control line 50 and the pressure in the second pressure medium line 16. In the direction of the blocking position, the locking piston 110 is further acted upon by a spring 111.

[0078] The bypass valve 45 is pilot-operated by the control valve 55, the control valve 55 actuating a pilot valve 120, which in the first switching position 120a connects the section of the control line 50 connected to the bypass valve 45 to the container 13 and in the second control position 120b connects the control line 50 to the control pressure source 56.

[0079] The pilot valve 120 is actuated by a spring 121 in the direction of the first control position 120a and by a pilot pressure present in a pilot line 122 in the direction of the second control position 120b. The pilot line 122, together with the brake release pressure line 36, is connected to the first port of the control valve 55, which is designed as a three-port, two-position valve.

[0080] The design of the control valve 55 of the Figure 7 corresponds to the design of the control valve 55 of the Figures 2 to 6, so that in a first control position 55a the control valve 55 connects the brake release pressure line 36 and the pilot line 122 led to the pilot valve 120 with the reservoir 13 and in a second control position 55b connects the brake release pressure line 36 and the pilot line 122 with the control pressure source 56.

[0081] In the exemplary embodiment of the Figure 7 is analogous to the embodiment of the Figure 4 The bypass valve 45 can additionally be actuated into the closed position by the pressure present in the first pressure medium line 15.

[0082] For this purpose, the control line 50 is connected to the control pressure source 56 and the first pressure medium line 15 by means of the changeover valve 90. The changeover valve 90 is connected at one outlet to the section of the control line 50 leading to the pilot valve 120, at one inlet to the section of the control line 50 connected to the control pressure source 56, and at another inlet to the first pressure medium line 15. In the exemplary embodiment of the Figure 7 connected to the delivery line 59 of the control pressure pump 58, which leads to the control valve 55.

[0083] The freewheeling valve 65 is arranged in the section of the control line 50 leading from the pilot valve 120 to the bypass valve 45, the design of which corresponds to the freewheeling valve 65 of the Figures 2 to 6 corresponds.

[0084] To brake the cable drum by means of the spring-applied brake device 9, for example when the control directional control valve device 10 is not actuated and is in the neutral position 10a, the control valve 55 and the freewheel valve 65 are not actuated, so that the control valve 55 is in the first control position 55a and the freewheel valve 65 is in the control position 65a. By relieving the brake release pressure line 36 and the pilot line 122 to the reservoir 13 in the first control position 55a of the control valve 55, the spring-applied brake 9 is actuated into the braking position by the spring device 35 and the pilot valve 120 is actuated into the first control position 120a by the spring 121, so that the section of the control line 50 to the reservoir 13 connected to the control surface 110c of the bypass valve 45 is relieved and the bypass valve 45 is opened to the flow position 45b by a slight pressure on one of the control surfaces 110a or 110b.The bypass valve device 45, located in the flow position 45b, ensures that the drive motor 2 or the cable drum is only braked by the mechanical braking torque of the spring-applied brake 9.

[0085] To release the spring-loaded brake device 9 of the cable drum, in the Figure 7The control valve 55 is actuated into the second control position 55b, in which the brake release pressure line 36 and the pilot line 122 are connected to the delivery line 59 of the feed pump 58, so that the spring-applied brake 9 is actuated into the release position by the delivery pressure provided by the feed pump 58 against the force of the spring device 35, and the pilot valve 120 is actuated into the second control position 120b by the pilot pressure present in the pilot line 122, in which, controlled by the changeover valve 90, either the delivery pressure of the feed pump 58 or the high pressure of the first pressure medium line 15 is applied to the control surface 110c of the locking piston 110, thereby acting the bypass valve device 45 into the locking position.

[0086] For high functional and operational reliability, whereby, when the control valve 55 is actuated to the second control position 55b, the bypass valve device 45 is actuated to the blocking position 45a first and subsequently the spring brake 9 is actuated to the release position, the following can be achieved in the Figure 7 analogous to Figure 2 The spring preloads are selected accordingly or analogously to Figure 3 The combination of two shut-off valves 70 and 72 is used in the brake release pressure line 36.

[0087] The exemplary embodiment of the Figure 7 is particularly suitable for a bypass valve device 45 with a large nominal diameter and enables, in the case of such a bypass valve, a safe actuation into the blocking position for separating the two pressure medium lines 15, 16 when releasing the spring-applied brake 9.

[0088] The invention is not limited to the embodiment shown in the figures.

[0089] In the Figures 1 to 5 and 7 Line 40 with shut-off valve 41 can also be omitted.

[0090] The embodiments of Figures 2 and 3 can each be used with the changeover valve 90 of the Figure 4 and / or the hydraulic control of the control valve 55 according to the Figure 5 and / or the further shut-off valve 101 according to the Figure 6 can be combined.

[0091] It goes without saying that in the Figure 7 also a hydraulic actuation of the control valve 55 analogous to Figure 5 and / or another shut-off valve 101 according to the Figure 6 can be used.

Claims

1. Forestry rope winch (1) having a rope drum (3) which is driven by a drive motor (2) and on which a rope (4) is wound, wherein the rope drum is operatively connected to a brake device (9), wherein the brake device (9) is configured as a spring brake which is loaded in the direction of a braking position by a spring device (35) and in the direction of a release position by a hydraulic brake-release pressure prevailing in a brake-release-pressure line (36), wherein the drive motor (2) is configured as a hydraulic motor which is connected by means of a first pressure-medium line (15) and a second pressure-medium line (16) to a directional-control-valve device (10) that controls the drive motor (2), wherein provision is made of a bypass-valve device (45) which connects the pressure-medium lines (15, 16) and which is arranged in a connecting line (46) connecting the two pressure-medium lines (15, 16) and which has a blocking position (45a) and a throughflow position (45b), wherein the bypass-valve device (45) is actuated in the direction of the blocking position (45a) by a hydraulic control pressure prevailing in a control line (50), wherein the spring brake (9) and the bypass-valve device (45) are jointly actuated by a control valve (55), wherein the control valve (55) controls the control pressure actuating the bypass-valve device (45) in the direction of the blocking position (45a), and the brake-release pressure actuating the spring brake (9) in the direction of the release position, in such a way that, with the spring brake (9) actuated into the release position, the bypass-valve device (45) is in a state loaded into the blocking position (45a) and, with the spring brake (9) actuated into the braking position, the bypass-valve device (45) is in a state loaded into the throughflow position (45b), wherein, in a first control position (55a) of the control valve (55), the spring brake (9) is in a state loaded into the braking position and the bypass-valve device (45) is in a state loaded into the throughflow position (45b) and, in a second control position (55b) of the control valve (55), the spring brake (9) is in a state loaded into the release position and the bypass-valve device (45) is in a state loaded into the blocking position (45a), characterized in that, with the control valve (55) actuated into the second control position (55b), firstly, in terms of time, the bypass-valve device (45) is actuated into the blocking position (45a) and subsequently, in terms of time, the spring brake (9) is loaded into the release position.

2. Forestry rope winch according to Claim 1, characterized in that the bypass-valve device (45) is actuated in the direction of the blocking position (45a) by the control pressure prevailing in the control line (50).

3. Forestry rope winch according to Claim 1 or 2, characterized in that the bypass-valve device (45) is configured as a bypass valve which is actuated directly by the control valve (55), wherein the control valve (55), in the first control position (55a), connects the brake-release-pressure line (36) and the control line (50) to a container (13) and, in the second control position (55b), connects the brake-release-pressure line (36) and the control line (50) to a control-pressure source (56).

4. Forestry rope winch according to Claim 1 or 2, characterized in that the bypass-valve device (45) is configured as a bypass valve which is pilot-controlled by the control valve (55), wherein the control valve (55) actuates a pilot-control valve (120) which, in the first switching position (120a), connects the control line (50) to a container (13) and, in the second control position (120b), connects the control line (50) to a control-pressure source (56), wherein the control valve (55), in a first control position (55a), connects the brake-release-pressure line (36) and a pilot-control line (122), routed to the pilot-control valve (120), to a container (13), and, in a second control position (55b), connects the brake-release-pressure line (36) and the pilot-control line (122) to a control-pressure source (56).

5. Forestry rope winch according to Claim 4, characterized in that the pilot-control valve (120) is actuated in the direction of the first control position (120a) by a spring (121) and in the direction of the second control position (120b) by the pilot-control pressure prevailing in the pilot-control line (122).

6. Forestry rope winch according to one of Claims 1 to 5, characterized in that the control line (50) is connected to the control-pressure source (56) and the first pressure-medium line (15) by means of a shuttle valve (90).

7. Forestry rope winch according to one of Claims 1 to 6, characterized in that, in the control line (50), there is arranged a freewheeling valve (65) which, in a first control position (65a), opens the control line (50) and, in a second control position (65b), relieves pressure in a portion, connected to the bypass-valve device (45), of the control line (50) to a container (13).

8. Forestry rope winch according to Claim 7, characterized in that the freewheeling valve (65) is actuatable in the direction of the first control position (65a) by a spring (66) and is actuatable in the direction of the second control position (65b) by an electrical actuating device (67), in particular a switching magnet.

9. Forestry rope winch according to one of Claims 1 to 8, characterized in that the control valve (55) is actuatable in the direction of the first control position (55a) by a spring (60) and in the direction of the second control position (55b) by an electrical actuating device (61), in particular a switching magnet.

10. Forestry rope winch according to one of Claims 1 to 8, characterized in that the directional-control-valve device (10) is actuated by hydraulic actuation pressures, wherein the control valve (55) is actuatable in the direction of the first control position (55a) by a spring (60) and in the direction of the second control position (55b) by the hydraulic actuation pressures of the directional-control-valve device (10).

11. Forestry rope winch according to one of Claims 1 to 10, characterized in that the spring device (35) of the spring brake (9) and a spring device (47), acting in the direction of the throughflow position (45b), of the bypass-valve device (45) or the spring device (121) of the pilot-control valve (120) are designed in such a way that, with the control valve (55) actuated into the second control position (55b), firstly, in terms of time, the bypass-valve device (45) is actuated into the blocking position (45a) and subsequently, in terms of time, the spring brake (9) is loaded into the release position.

12. Forestry rope winch according to one of Claims 1 to 10, characterized in that a spring-preloaded shut-off valve (70), in particular check valve, that opens in the direction of the spring brake (9) is arranged in the brake-release-pressure line (36).

13. Forestry rope winch according to Claim 12, characterized in that a non-preloaded shut-off valve (72), in particular check valve, that opens in the direction of the control valve (55) is arranged in a bypass line (71) which bypasses the spring-preloaded shut-off valve (70).

14. Forestry rope winch according to one of Claims 1 to 13, characterized in that a spring-preloaded shut-off valve (41), in particular check valve, that opens in the direction of the first pressure-medium line (15) is arranged in a line (40) which connects the first pressure-medium line (15) to the second pressure-medium line (16).

15. Forestry rope winch according to one of Claims 1 to 14, characterized in that the forestry rope winch (1) is provided with an ejector roller (7) for the rope (4) that is driven by a further drive motor (6), wherein the further drive motor (6) is configured as a hydraulic motor which is connected by means of a first connection line (25) and a second connection line (26) to a directional-control-valve device (20) that controls the further drive motor (6).

16. Forestry rope winch according to Claim 15, characterized in that a non-preloaded shut-off valve (101), in particular check valve, that opens in the direction of the first pressure-medium line (15) is arranged in a connecting line (100) which connects the first pressure-medium line (15) to the second pressure-medium line (16), wherein, in the connecting line (100), there is arranged a valve (102) which is controlled by the pressure in the first connection line (25) and which has a blocking position (102a) and a throughflow position (102b).

17. Forestry rope winch according to Claim 16, characterized in that the valve (102) is actuated in the direction of the throughflow position (102b) by a spring (103) and in the direction of the blocking position (102a) by the pressure in the first connection line (25).

18. Mobile working machine, in particular a remote-controlled mobile working machine without a driver's workstation, having a forestry rope winch (1) according to one of the preceding claims.