JP2011057047A - Hydraulic system switching traction system and traction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that a worker erroneously releases a different valve and a working time is required for seeking a suitable valve in order to release differential pressure between a pressure oil feeding side to a hydraulic motor and a pressure oil discharge side since a large number of valves are arranged on a hydraulic traveling vehicle. <P>SOLUTION: The traction device for releasing an oil pressure of the hydraulic motor when the hydraulic traveling vehicle is towed by the towing vehicle includes a throttle valve capable of performing switching to the closed state that it is fluidly connected between a pressure oil feeding side conduit of the hydraulic motor and a pressure oil discharge side conduit and a pressure oil flow is not generated between the pressure oil feeding side conduit and the pressure oil discharge side conduit and the opened state that the pressure oil flow is generated between the pressure oil feeding side conduit and the pressure oil discharge side conduit; a towing bar connected for traction of the towing vehicle and the hydraulic traveling vehicle; and a switching head for switching the throttle valve from the closed state to the opened state. The problem is solved by the above traction device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a traction system and a traction device that, when towing a hydraulic traveling vehicle with another vehicle, releases the hydraulic pressure to the hydraulic motor in conjunction with the traction operation and allows the hydraulic motor to freely rotate and tow.

  As shown in FIG. 6, the hydraulic traveling vehicle that is self-propelled by driving of the hydraulic motor 18 has a hydraulic circuit unit 10. The hydraulic circuit unit 10 includes a pressure oil conduit that supplies pressure oil to the hydraulic motor 18 for traveling, and a hydraulic safety circuit 11. The pressure oil line of the hydraulic circuit unit 10 is connected to a hydraulic pressure supply pump 14 driven by a motor 15 via a travel direction switching valve 16. The hydraulic supply pump 14 supplies the hydraulic motor 18 with pressure oil necessary for traveling (forward and backward). By switching the traveling direction switching valve 16, the direction of pressure oil supply in the hydraulic circuit unit 10 can be changed by changing the direction of pressure oil supply in the hydraulic circuit unit 10. As a result, the hydraulic traveling vehicle 21 can move forward and backward. By switching the traveling direction switching valve 16 to neutral and shutting off the supply of pressure oil to the hydraulic circuit unit 10, the supply of pressure oil to the hydraulic motor 18 can be stopped while the hydraulic supply pump 14 is driven. When the supply of pressure oil stops, the hydraulic motor 18 stops and the hydraulic vehicle stops.

  When the traveling direction switching valve 16 is switched to neutral and the supply of pressure oil to the hydraulic circuit unit 10 is shut off, the hydraulic motor 18 continues to rotate due to inertia. When the hydraulic motor 18 rotates due to inertia in a state where no pressure oil is supplied, the upstream side where the pressure oil was supplied is depressurized and the downstream side is increased in pressure, which is dangerous. Therefore, the hydraulic safety circuit 11 prevents excessive pressure increase and pressure decrease in the pressure oil pipeline. Further, since the load on the hydraulic pressure supply pump 14 is generated by switching the traveling direction switching valve 16 to neutral, the relief valve 17 is arranged to reduce this load.

  When such a hydraulic traveling vehicle is towed by, for example, a towing vehicle, the hydraulic circuit unit 10 needs to release the hydraulic pressure applied to the hydraulic motor 18 so that the hydraulic motor 18 can freely rotate. In the conventional hydraulic circuit unit 10, a short circuit line 19 a that is fluidly connected to a pressure oil supply side pipe line to the hydraulic motor 18 and a short circuit that is fluidly connected to a pressure oil discharge side pipe line from the hydraulic motor 18. A conduit 19b is provided. If the throttle valve 19 is disposed between the short-circuit line 19a and the short-circuit line 19b and the throttle valve 19 is closed and pressure oil is supplied, the pressure-oil supply side line to the hydraulic motor 18 and the hydraulic motor 18 The hydraulic motor 18 can be driven by applying hydraulic pressure to the pressure oil discharge side pipe line from the pipe. On the other hand, if the supply of pressure oil is stopped and the throttle valve 19 is opened, the differential pressure between the pressure oil supply side pipe line to the hydraulic motor 18 and the pressure oil discharge side pipe line from the hydraulic motor 18 is released. The free rotation of the hydraulic motor 18 becomes possible. Conventionally, the throttle valve 19 is arranged as a valve that is manually opened and closed, or a valve that is operated via a manual hydraulic pump, as disclosed in, for example, Patent Document 1.

Japanese Utility Model Publication No. 5-51893

  Since the conventional throttle valve 19 is a manual type, it is necessary to open the throttle valve 19 in a preparatory work as a pre-stage of the pulling work of the hydraulic traveling vehicle. In addition, the towing operation of the hydraulic traveling vehicle is not a universal operation that is always performed, but is a temporary operation in an emergency or the like, and it is difficult to prepare a worker skilled in this operation.

  In general, not only the throttle valve 19 but many valves are arranged in the hydraulic traveling vehicle. Therefore, in order to release the differential pressure between the pressure oil supply side pipe line to the hydraulic motor 18 and the pressure oil discharge side pipe line from the hydraulic motor 18, an operator accidentally opens a valve different from the throttle valve 19. There is a problem that it takes a long time for an unskilled worker to search for the throttle valve 19 and becomes an obstacle in emergency work. Therefore, it is convenient if the towing operation of the hydraulic traveling vehicle leads to the opening of the throttle valve 19.

  When the towing vehicle pulls the hydraulic traveling vehicle, the towing vehicle is towed by a towbar or a rope. This is solved by a towing device configured to release the hydraulic pressure that is automatically applied to the hydraulic motor when the tow bar or the rope is pulled by the towing vehicle and is urged by the tober operation or the posture of the tober.

  According to the present invention, when towing a hydraulic traveling vehicle with a towing vehicle, if the towing work is performed, the worker can automatically open the throttle valve without being aware of the opening of the throttle valve, The throttle valve can be easily opened even in an emergency operation by an unfamiliar worker.

It is the figure which showed the hydraulic circuit unit of this invention. It is the figure which showed the hydraulic traveling vehicle of the traction state using the traction system of 1st Embodiment. It is a traction system of a 1st embodiment, and is a figure showing the state where a throttle valve is closed. It is a traction system of a 1st embodiment, and is a figure showing the state where a throttle valve is opened. It is the figure which showed the hydraulic traveling vehicle of the traction state using the traction system of 2nd Embodiment. It is a traction system of a 2nd embodiment, and is a figure showing the state where a throttle valve is closed. It is a traction system of a 2nd embodiment, and is a figure showing the state where a throttle valve is opened. It is the figure which showed the hydraulic circuit unit of the prior art.

Hereinafter, a traction system and a traction device according to a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3A and 3B.
(First embodiment)
FIG. 1 is a view showing a hydraulic circuit unit 10 used in a traction system and a traction device of the present invention. FIG. 2 is a view showing a towing vehicle 20 and a hydraulic traveling vehicle 21 in a towing state using the towing system of the present embodiment. 3A and 3B show the traction system of this embodiment, FIG. 3A shows a state in which the throttle valve 9 is closed, and FIG. 3B shows a state in which the throttle valve 9 is opened. It is.

  As shown in FIG. 2, in this embodiment, the towing vehicle 20 is used to pull the hydraulic traveling vehicle 21 by the rotating rigid towbar 4. The tow vehicle 20 and the hydraulic traveling vehicle 21 can be connected by the tow bar 4. The hydraulic circuit unit 10 is mounted on the hydraulic traveling vehicle 21. As shown in FIGS. 1 and 2, the traction system of the present invention includes a traction device 1 and a hydraulic circuit unit 10. Further, the traction device 1 of the present invention includes a tober 4, a short-circuit line 10a, a short-circuit line 10b, a throttle valve 9, and a switching head 9a that switches the throttle valve 9 from a closed state to an open state.

  As shown in FIG. 1, the hydraulic circuit unit 10 of the traction system of the present invention includes a hydraulic motor 18 as a power source for traveling and a pressure oil pipe for supplying pressure oil to the hydraulic motor 18, as in the conventional system. And a hydraulic safety circuit 11. In the hydraulic circuit unit 10, the pipe line is connected to a hydraulic pressure supply pump 14 driven by a motor 15 via a travel direction switching valve 16. Supply of the pressure oil for traveling and the pressure oil for stopping is performed from the hydraulic supply pump 14, and the direction of the pressure oil supply in the hydraulic circuit unit 10 can be switched by switching the traveling direction switching valve 16. It is possible to move forward and backward. If the supply of pressure oil to the hydraulic circuit unit 10 is interrupted by switching the traveling direction switching valve 16, it is possible to stop the pressure oil to the hydraulic motor 18 while driving the hydraulic supply pump 14. In order to reduce the load on the hydraulic pressure supply pump 14 in this case, a relief valve 17 is arranged. These points are the same as those of the conventional apparatus.

  In the traction device 1 of the present invention, the short circuit line 10a and the short circuit line 10b are fluidly connected to the lines for supplying or discharging the pressure oil to the hydraulic motor 18 of the hydraulic circuit unit 10, respectively. Yes. For example, the short circuit conduit 10 a is fluidly connected to the pressure oil supply side conduit of the hydraulic motor 18, and the short circuit conduit 10 b is fluidly connected to the pressure oil discharge side conduit from the hydraulic motor 18. If the recirculation direction of the pressure oil is reversed by switching the traveling direction switching valve 16, the conduit to the hydraulic motor 18 to which the short circuit conduit 10a is fluidly connected becomes the pressure oil discharge side conduit, and the short circuit conduit The pipe to the hydraulic motor 18 to which the fluid 10b is fluidly connected is changed to become a pressure oil supply side pipe, and the rotation of the hydraulic motor 18 can be changed.

  The short-circuit line 10 a and the short-circuit line 10 b are fluidly connected to each other via the mechanical throttle valve 9. The mechanical throttle valve 9 is normally in a closed state. In the closed state, no pressure oil flow is generated between the short-circuit line 10a and the short-circuit line 10b, and a hydraulic pressure is applied to the hydraulic motor 18. The hydraulic motor 18 does not rotate freely when the hydraulic motor 18 is under hydraulic pressure. When the switching head 9a of the mechanical throttle valve 9 is pushed, the mechanical throttle valve 9 is opened. In the open state, a pressure oil flow is generated between the short circuit line 10a and the short circuit line 10b, and the pressure difference between the pressure oil supply side line and the pressure oil supply side line to the hydraulic motor 18 is released, and the hydraulic motor The hydraulic pressure is released at 18. If the differential pressure between the pressure oil supply side pipe line and the pressure oil supply side pipe line to the hydraulic motor 18 is released, the hydraulic motor 18 can freely rotate.

  In the present invention, as shown in FIG. 2, the short circuit line 10 a and the short circuit line 10 b are extended from the hydraulic circuit unit 10 to the traction side (traction vehicle 20 side) of the hydraulic traveling vehicle 21. Then, the mechanical throttle valve 9 is disposed in the vicinity of the tow bar 4. The mechanical throttle valve 9 is arranged so that the switching head 9a of the mechanical throttle valve 9 extends from the hydraulic traveling vehicle 21 toward the towing vehicle 20 side.

  The tober 4 is a rigid bar. A pushing member 2 is attached to one end side of the tow bar 4. A push plate 2 a is attached to one end of the push member 2.

  When the hydraulic traveling vehicle 21 is not towed, one end of the tow bar 4 is disposed away from the switching head 9 a of the mechanical throttle valve 9. The other end of the tow bar 4 can be connected to the towing vehicle 20. When the tow vehicle 20 pulls the hydraulic traveling vehicle 21, the towing vehicle 20 and the hydraulic traveling vehicle 21 are connected by the tow bar 4. In the connected state, one end of the tow bar 4 operates so as to approach the switching head 9a of the mechanical throttle valve 9, and the push plate 2a of the pushing member 2 pushes the switching head 9a of the mechanical throttle valve 9 to move the machine. The hydraulic throttle valve 9 is opened and a pressure oil flow is generated between the short circuit line 10a and the short circuit line 10b, and the pressure difference between the pressure oil supply side line and the pressure oil supply side line to the hydraulic motor 18 is reduced. Canceled.

  The tow bar 4 may be fixed to the hydraulic traveling vehicle 21 or to the towing vehicle 20. Alternatively, a method may be used in which attachment is performed during towing without being fixed to either the towing vehicle 20 or the hydraulic traveling vehicle 21. In a state in which the tow vehicle 20 and the hydraulic traveling vehicle 21 are connected by the tow bar 4, one end of the tow bar 4 pushes the switching head 9a of the mechanical throttle valve 9 to open the mechanical throttle valve 9 to open the short circuit line 10a. It is only necessary to generate a pressure oil flow between the pipe 10b and the short circuit pipe 10b. This will be described below.

  As an example of fixing one end of the tow bar 4 to the hydraulic traveling vehicle 21, for example, a configuration as shown in FIG. 3A can be considered. FIG. 3A shows the tow bar 4 that is pivotably mounted around the pivot shaft 5 and is not pulled. That is, one end of the tow bar 4. The hydraulic traveling vehicle 21 is fixed so as to be rotatable around a rotation shaft 5 disposed on the pulling side. The other end of the tow bar 4 can be connected to the towing vehicle 20. The rotating shaft 5 is preferably arranged in the vicinity of the switching head 9 a of the mechanical throttle valve 9 of the hydraulic traveling vehicle 21.

  When the hydraulic traveling vehicle 21 is towed by the tow vehicle 20, the tow bar 4 in the non-towed state illustrated in FIG. 3A is rotated so that the other end of the tow bar 4 approaches the towed vehicle 20. In response to the rotational movement of the tow bar 4, one end of the tow bar 4 moves so as to approach the switching head 9 a of the mechanical throttle valve 9. As one end of the tow bar 4 approaches the switching head 9 a of the mechanical throttle valve 9, the pushing plate 2 a of the pushing member 2 comes into contact with the switching head 9 a of the mechanical throttle valve 9 by the rotating operation of the tow bar 4. At this time, the switching head 9a of the mechanical throttle valve 9 is preferably a rotating roller, and the surface shape of the push plate 2a is preferably a curved surface. As a result, a further rotating operation of the tow bar 4 is aroused, and the push plate 2a gradually and smoothly pushes the switching head 9a of the mechanical throttle valve 9 so as to rub the rotating roller of the switching head 9a. Open the type switching valve. In this way, the operation of the tow bar 4 urges the movement of the switching head 9a via the push member 2, whereby the mechanical throttle valve 9 is switched from the closed state to the open state.

  Note that the switching head 9a of the mechanical throttle valve 9 has already been completely pushed in the middle of the rotational operation of the tow bar 4 before the other end of the tow bar 4 is connected to the towing vehicle 20, so that the mechanical throttle valve 9 is completely Sometimes it is opened. In this case, it is conceivable that an excessive load is applied to the tow bar 4 or the switching head 9a. Therefore, the pressing member 2 is attached so that one end of the spring 3 is fixed to the pressing member 2 and the other end of the spring 3 is fixed to the torbar 4 via the spring 3. As a result, when the switching head 9a of the mechanical throttle valve 9 is completely pushed in and the mechanical throttle valve 9 is completely opened, an unreasonable load is applied even if the rotation operation of the tow bar 4 is not completed. It does not take.

  FIG. 3B shows a state in which the tow bar 4 finishes the pivoting operation and the other end of the tow bar 4 can be connected to the towing vehicle 20. In a state where the tow bar 4 finishes the turning operation until one end of the tow bar 4 is positioned at a predetermined position of the hydraulic traveling vehicle 21 and can be connected to the towing vehicle 20, the push plate 2 a is the switching head 9 a of the mechanical throttle valve 9. Is completely pushed in, and the mechanical throttle valve 9 is opened. Then, a pressure oil flow is generated between the short circuit line 10a and the short circuit line 10b, and the differential pressure between the pressure oil supply side line and the pressure oil supply side line to the hydraulic motor 18 is released. The hydraulic traveling vehicle 21 can be pulled. In the claims and specification of the present application, the predetermined position means that the tow bar 4 that is scheduled from the beginning with respect to the hydraulic traveling vehicle 21 in a state in which the hydraulic traveling vehicle 21 can be towed by the towing vehicle 20. It is the position of one end. In the first embodiment, one end of the tow bar 4 is connected to the rotating shaft 5 of the hydraulic traveling vehicle 21, and the other end of the tow bar 4 is connected to the hydraulic traveling vehicle 21.

Note that, as in the case described above, one end of the tow bar 4 may be fixed to the hydraulic traveling vehicle 21 so as to be pivotable to the hydraulic traveling vehicle 21 in a state in which it is not detachable from the pivot shaft 5. It is also possible to attach it and allow it to function in the same manner as above (not shown). That is, one end of the tow bar 4 may be configured to be engageable with the rotating shaft 5, and the one end of the tow bar 4 may be rotated around the rotating shaft 5 after being engaged. For example, a configuration in which a notch is provided at one end of the tow bar 4 or the axial direction of the rotating shaft 5 in order to lock the one end of the tow bar 4 to the hydraulic traveling vehicle 21 so as to be rotatable on the rotating shaft 5. It can be considered that one end is fitted.
Furthermore, the towbar 4 does not necessarily have to be rotated. It is conceivable that one end of the tow bar 4 is detachably locked to the hydraulic traveling vehicle 21 for attachment. In this case, the locking portion is arranged in advance on the hydraulic traveling vehicle 21. One end of the tow bar 4 has an attachment portion that can be engaged with the locking portion. Then, the attachment portion at one end of the tow bar 4 is locked to the locking portion. When the one end of the tow bar 4 is engaged with the engaging portion, the posture of the tow bar 4 is urged, and the push plate 2a of the push member 2 comes into contact with the switching head 9a of the mechanical throttle valve 9, and gradually the mechanical throttle valve 9 The switching head 9a is pushed in. When one end of the tow bar 4 is positioned at a predetermined position of the hydraulic traveling vehicle 21 necessary for the connection, the switching head 9a of the mechanical throttle valve 9 is pushed in to be opened. In this way, the posture of the tow bar 4 urges the movement of the switching head 9a via the push member 2, whereby the mechanical throttle valve 9 is switched from the closed state to the opened state, and the tow bar 4 is hydraulically driven. It functions similarly to the case where it is attached to the vehicle 21 so as to be rotatable.

  On the other hand, contrary to the above case, the tow bar 4 can be fixed to the towing vehicle 20 and functions in the same manner (not shown). At this time, it is also preferable that the switching head 9a of the mechanical throttle valve 9 is a rotating roller and the surface shape of the push plate 2a is a curved surface. Similarly, the pressing member 2 is attached so that one end of the spring 3 is fixed to the pressing member 2 and the other end of the spring 3 is fixed to the torbar 4 via the spring 3.

  In this case, one end of the tow bar 4 can be connected to the hydraulic traveling vehicle 21. The pivot shaft is disposed on the towing vehicle 20. The other end of the tow bar 4 is attached so as to be rotatable around a rotation axis disposed on the towing vehicle 20. When the hydraulic traveling vehicle 21 is towed by the towing vehicle 20, the towbar in the retracted state is rotated around the rotation shaft on the other end side of the towbar 4 so that one end of the towbar 4 approaches the hydraulic traveling vehicle 21. 4 is rotated. In accordance with the rotation operation of the tow bar 4, one end of the tow bar 4 moves so as to approach the switching head 9 a of the mechanical throttle valve 9 of the hydraulic traveling vehicle 21. As one end of the tow bar 4 approaches the switching head 9a of the mechanical throttle valve 9, the tow bar 4 is urged to rotate, and the push plate 2a of the pushing member 2 contacts the switching head 9a of the mechanical throttle valve 9. Then, the switching head 9a of the mechanical throttle valve 9 is gradually pushed in to open the mechanical throttle valve 9. In a state where the toe bar 4 has finished the pivoting operation until one end of the toe bar 4 is positioned at a predetermined position of the hydraulic traveling vehicle 21 required for connection with the hydraulic traveling vehicle 21, the mechanical switching valve 9 is opened. . In this way, the operation of the tow bar 4 urges the movement of the switching head 9a via the push member 2, whereby the mechanical throttle valve 9 is switched from the closed state to the open state.

Note that, as in the case described above, the other end of the towbar 4 may be configured to be pivotably fixed to the towing vehicle 20 in a state in which the towbar 4 cannot be detached from the pivot shaft. It is also possible to attach it to function as described above (not shown). In other words, the other end of the tow bar 4 may be configured to be engageable with the rotation shaft, and the other end of the tow bar 4 may be rotated around the rotation shaft after the engagement. For example, a configuration in which a notch is provided in the other end of the tow bar 4 in order to lock the other end of the tow bar 4 to the rotation shaft of the towing vehicle 20 or the other of the tow bar 4 from the axial direction of the rotation shaft. It can be considered that the end is fitted.
Furthermore, the towbar 4 does not necessarily have to be rotated. It is also conceivable that the other end of the tow bar 4 is detachably locked to the towing vehicle 20 and attached. In this case, the locking portion is arranged on the towing vehicle 20 in advance. The other end of the tow bar 4 has an attachment portion that can be engaged with the locking portion. Then, the attachment portion at the other end of the tow bar 4 is locked to the locking portion. At that time, the posture of one end of the tow bar 4 on the hydraulic traveling vehicle 21 side is aroused, the push plate 2a of the push member 2 contacts the switching head 9a of the mechanical throttle valve 9, and gradually the switching head of the mechanical throttle valve 9 Push 9a. When one end of the tow bar 4 is positioned at a predetermined position of the hydraulic traveling vehicle 21 necessary for the connection, the switching head 9a of the mechanical throttle valve 9 is pushed in to be opened. In this way, the posture of the tow bar 4 urges the movement of the switching head 9a via the push member 2, whereby the mechanical throttle valve 9 is switched from the closed state to the open state. As a result, it functions in the same manner as when the tow bar 4 is pivotally attached to the towing vehicle 20.

(Second Embodiment)
Next, a second embodiment of the traction system and traction device of the present invention will be described with reference to FIGS. 1, 4, 5A and 5B. FIG. 4 is a diagram showing a tow vehicle 20 and a hydraulic traveling vehicle 21 in a towing state using the tow system 1 of the present embodiment. 5A and 5B show the traction system 1 of the present embodiment, FIG. 5A is a diagram showing a non-traction state in which the throttle valve 9 is closed, and FIG. 5B is a diagram showing that the throttle valve 9 is opened. It is the figure which showed the state at the time of towing. As shown in FIG. 4, the traction system or traction device of the present embodiment is used when the hydraulic traveling vehicle 21 is towed using the rigid towbar 7 that translates in the axial direction of the towbar 7. Different from one embodiment.

  The traction system according to the second embodiment also includes a traction device 1 and a hydraulic circuit unit 10. The hydraulic circuit unit 10 is mounted on a hydraulic traveling vehicle 21. The hydraulic circuit unit 10 (FIG. 1) in the second embodiment is the same as that in the first embodiment.

  In addition, the traction device 1 of the present invention includes a tow bar 7, a short circuit line 10 a, a short circuit line 10 b, and a throttle valve 9. Hereinafter, the description of the same parts as those of the first embodiment will be omitted, and the parts different from those of the first embodiment will be particularly described. Similarly to the first embodiment, in the hydraulic circuit unit 10, in the closed state, no pressure oil flow is generated between the short-circuit pipe line 10 a and the short-circuit pipe line 10 b, and the oil pressure is applied to the hydraulic motor 18. It is. The hydraulic motor 18 does not rotate freely when the hydraulic motor 18 is under hydraulic pressure. When the switching head 9a of the mechanical throttle valve 9 is pushed, the mechanical throttle valve 9 is opened. In the open state, a pressure oil flow is generated between the short circuit line 10a and the short circuit line 10b, and the pressure difference between the pressure oil supply side line and the pressure oil supply side line to the hydraulic motor 18 is released, and the hydraulic motor The hydraulic pressure is released at 18. If the differential pressure between the pressure oil supply side pipe line and the pressure oil supply side pipe line to the hydraulic motor 18 is released, the hydraulic motor 18 can freely rotate.

  In the present embodiment, the configurations of the short-circuit conduit 10a and the short-circuit conduit 10b of the traction device 1 and the switching head 9a of the mechanical throttle valve 9 are the same as those of the first embodiment, as with the hydraulic circuit unit 10. . Also in the present embodiment, as shown in FIG. 4, the short circuit line 10 a and the short circuit line 10 b are extended from the hydraulic circuit unit 10 to the traction side (traction vehicle 20 side) of the hydraulic traveling vehicle 21. The mechanical throttle valve 9 is disposed in the vicinity of the tow bar 7. The mechanical throttle valve 9 is arranged so that the switching head 9a of the mechanical throttle valve 9 extends from the hydraulic traveling vehicle 21 toward the side opposite to the towing vehicle 20.

  The tow bar 7 is a rigid bar. The tow bar 7 is attached to a frame member 21 a fixed to the hydraulic traveling vehicle 21 so that a connection point with the towing vehicle 20 is located on an extension line of the longitudinal axis of the tow bar 7. The tow bar 7 is slidable with respect to the frame member 21 a by a force (traction force) that pulls the hydraulic traveling vehicle 21 by the towing vehicle 20. An attachment plate 6 is attached to one end side of the tow bar 7. A push member 2 is attached to the attachment plate 6 so that the longitudinal axis thereof extends in parallel with the sliding direction of the tow bar 7. A push plate 2 a is attached to one end of the push member 2. The mounting plate 6 is urged by a return spring 23 in a direction (the direction of the arrow in FIGS. 5A and 5B) opposite to the direction in which the tow bar 7 slides when receiving the traction force (the direction in which the traction force is generated). .

  FIG. 5A shows the tow bar 7 in which the tow vehicle 20 is not towed. When the hydraulic traveling vehicle 21 is not towed, the mounting plate 6 disposed on one end side of the tow bar 7 is positioned away from the switching head 9 a of the mechanical throttle valve 9. The other end of the towbar 7 can be connected to the towing vehicle 20 directly or via a rope 22. In the connected state, the mounting plate 6 on one end side of the tow bar 7 operates so as to approach the switching head 9 a of the mechanical throttle valve 9, and the pressing plate 2 a of the pressing member 2 switches the mechanical throttle valve 9. The mechanical throttle valve 9 is opened by pushing the head 9a and a pressure oil flow is generated between the short circuit line 10a and the short circuit line 10b, and the pressure oil supply side line and the pressure oil supply side line to the hydraulic motor 18 are generated. Is released. The following is a case where the vehicle is connected to the towing vehicle 20 via the rope 22.

  When the hydraulic traveling vehicle 21 is towed by the tow vehicle 20, the other end of the tow bar 7 is connected to the rope 22 that is connected to the tow vehicle 20 at one end. In this state, it is preferable that almost no tension is applied to the rope 22. Subsequently, the tow vehicle 20 travels, tension is generated on the rope 22, and the tow of the hydraulic traveling vehicle 21 is started. The towbar 7 in the non-traction state shown in FIG. 5A starts to slide toward the traction vehicle 20 with respect to the frame member 21 a fixed to the hydraulic traveling vehicle 21. As the tow bar 7 slides toward the tow vehicle 20, the mounting plate 6 attached to one end of the tow bar 7 also moves toward the tow vehicle 20 side. Further, as the mounting plate 6 moves toward the towing vehicle 20, the push plate 2 a of the push member 2 approaches the switching head 9 a of the mechanical throttle valve 9, and eventually the push plate 2 a of the push member 2 is moved to the mechanical throttle valve 9. Contact the switching head 9a. From here, the tow bar 7 slides and the push plate 2a gradually pushes the switching head 9a. When the tow bar 7 slides and one end of the tow bar 7 is positioned at a predetermined position, the push plate 2a gradually pushes the switching head 9a and opens the mechanical throttle valve 9. Thus, the sliding operation of the tow bar 7 urges the movement of the switching head 9a via the push member 2, whereby the mechanical throttle valve 9 is switched from the closed state to the open state. The predetermined position is a position of one end of the tow bar 7 scheduled from the beginning with respect to the hydraulic traveling vehicle 21 in a state where the hydraulic traveling vehicle 21 can be towed by the towing vehicle 20. In the second embodiment, the tow bar 7 is loaded with a traction force and slid in the direction in which the traction force is loaded.

  In some cases, the sliding of the tow bar 7 may still continue even after the switching head 9a of the mechanical throttle valve 9 is completely pushed and the mechanical throttle valve 9 is completely opened. In this case, since it is considered that an excessive load is applied to the tow bar 7 or the switching head 9a, the pushing member 2 has one end of the spring 3 to the pushing member 2 and the other end of the spring 3 to the tow bar 7. It is attached so as to be fixed to the tow bar 7 via the spring 3. As a result, when the switching head 9a of the mechanical throttle valve 9 is completely pushed in and the mechanical throttle valve 9 is completely opened, even if the sliding operation of the tow bar 7 is not finished, an unreasonable load is applied. It does not take.

  As long as the tow vehicle 20 travels forward and tension is generated in the rope 22, sliding of the tow bar 7 in the arrow direction is completed as shown in FIG. 5B, and the switching head 9a of the mechanical throttle valve 9 is moved. Fully pushed in, the mechanical throttle valve 9 is fully opened. When the mechanical throttle valve 9 is opened, a pressure oil flow is generated between the short circuit line 10a and the short circuit line 10b, and the pressure difference between the pressure oil supply side line and the pressure oil supply side line to the hydraulic motor 18 is generated. Is released. Even if the tow bar 7 is directly connected to the towing vehicle 20 without using the rope 22, the switching head 9a of the mechanical throttle valve 9 is pushed by the sliding of the tow bar 7, so that the mechanical throttle valve 9 is completely The same effect is produced in that it is released. When the towing vehicle 20 is towing the hydraulic traveling vehicle 21, the mechanical throttle valve 9 is kept open.

  Even when the tow bar 7 receives the traction force by the return spring 23 and the mounting plate 6 moves thereby, the tow vehicle 20 decelerates or stops, the traction rope 22 is loosened, and the traction force is no longer applied to the tow bar 7. The mounting plate 6 can return to the position before the traction force is applied. Thus, the state can be accurately switched so that the throttle valve 9 is completely opened during traction and the throttle valve 9 is immediately closed during non-traction when the traction force is not applied. As a result, the tow vehicle 20 can prevent the towed hydraulic traveling vehicle 21 from continuing to travel due to inertia and colliding with the towing vehicle 20 when the towing vehicle 20 decelerates or stops. Further, a damper (not shown) can be used instead of the return spring 23. The damper is attached so that the attachment plate 6 is biased in a direction away from the frame member 21 a fixed to the hydraulic traveling vehicle 21. Thereby, the same effect as the return spring 23 is produced.

  The throttle valve 9 can be not only a mechanical type but also a solenoid valve (electromagnetic throttle valve 9). When the switching head 9a is pushed, the switch of the electromagnetic throttle valve 9 is turned on, and when the switching head 9a is pushed, the switch of the electromagnetic throttle valve 9 is turned off. If the switch of the electromagnetic throttle valve 9 is turned on and off, the present invention can be applied to both cases of the first embodiment and the second embodiment.

DESCRIPTION OF SYMBOLS 1 Pulling device 2 Pushing member 3 Spring 4 Tober (1st Embodiment)
5 Rotating shaft 6 Mounting plate 7 Tober (second embodiment)
9 Mechanical throttle valve 10 Hydraulic circuit units 10a, 10b Short circuit 18 Hydraulic motor

Claims (11)

A traction device that releases hydraulic pressure of the hydraulic motor when the hydraulic traveling vehicle that is self-propelled by driving of the hydraulic motor is towed by the towing vehicle,
The hydraulic motor is fluidly connected between a pressure oil supply side pipe and a pressure oil discharge side pipe, and a pressure oil flow between the pressure oil supply side pipe and the pressure oil discharge side pipe A throttle valve that can be switched between a closed state that does not occur and an open state that generates a pressure oil flow between the pressure oil supply side pipe and the pressure oil discharge side pipe,
A tow bar having one end connected to the towing vehicle and the other end connected to the hydraulic traveling vehicle;
A traction device comprising a switching head for switching the throttle valve from the closed state to the open state,
When one end of the tow bar is positioned at a predetermined position of one end of the tow bar that is initially planned for the hydraulic traveling vehicle in a state where the hydraulic traveling vehicle is capable of being pulled by the tow vehicle, one end of the tow bar Pushes the switching head to bring the throttle valve into the open state. The traction device according to claim 1,
The towbar is rotatably attached to the hydraulic vehicle,
The operation of pushing the switching head by one end of the towbar is caused by arousing the movement of the switching head by the rotation of the tober, whereby the throttle valve is changed from the closed state to the open state. Traction device. The traction device according to claim 1,
The towbar is pivotally attached to the tow vehicle,
The operation of pushing the switching head by one end of the towbar is caused by arousing the movement of the switching head by the rotation of the tober, whereby the throttle valve is changed from the closed state to the open state. Traction device. The traction device according to claim 1,
The towbar is detachable from the tow vehicle and the hydraulic vehicle,
The action of one end of the towbar pushing the switching head is caused by arousing the movement of the switching head by the attitude of the towbar when the one end of the towbar is connected to the hydraulic vehicle. A traction device that is changed from a closed state to an open state. The traction device according to claim 1,
The towbar is slidable on the hydraulic traveling vehicle by a force with which the towing vehicle pulls the hydraulic traveling vehicle;
The operation of one end of the tow bar pushing the switching head occurs when the tow bar is slid by the pulling force to urge the movement of the switching head, whereby the throttle valve is moved from the closed state to the opened state. A traction device characterized by being switched. The traction device according to claim 5,
When the towing vehicle is towing the hydraulic traveling vehicle, the throttle valve is in the open state. A traction device according to claim 5 or 6,
When the pulling force is no longer applied, the tow bar returns to its original position, and the throttle valve returns to the closed state. The traction device according to any one of claims 1 to 4,
The traction device, wherein the throttle valve is a mechanical switching valve from the closed state to the open state. The traction device according to any one of claims 1 to 4,
The throttle valve is a solenoid valve, and the switching head urges the switch of the solenoid valve to be turned on and off to switch from the closed state to the open state. A traction system that releases hydraulic pressure of the hydraulic motor when the hydraulic traveling vehicle that is self-propelled by driving of the hydraulic motor is towed by the towing vehicle,
A traction device according to any one of claims 1 to 4;
A traction system including a hydraulic circuit including the hydraulic motor. A traction system that releases hydraulic pressure of the hydraulic motor when the hydraulic traveling vehicle that is self-propelled by driving of the hydraulic motor is towed by the towing vehicle,
A traction device according to claim 5 or 6,
A traction system including a hydraulic circuit including the hydraulic motor.

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