Garbage collection vehicle

Abstract

To provide a garbage collection vehicle in which a discharge plate can be moved forward upon loading garbage.SOLUTION: A garbage collection vehicle comprises: a garbage storage box 23; a garbage input box 2; a discharge plate 24 provided within the garbage storage box 23; a discharge actuator 25 connected to the discharge plate 24; and a hydraulic circuit. The garbage storage box 23 comprises a discharge port 23A connected to the outside of the box. The garbage input box 2 comprises a loading device 27. The discharge plate 24 is provided reciprocatingly between the side of the discharge port 23A and the depth side of the garbage storage box 23 at the inside of the garbage storage box. The discharge actuator 25 is configurated to reciprocate the discharge plate 24. The hydraulic circuit includes a switching valve and an oil tank. The switching valve is provided at an oil path connecting the discharge actuator 25 and the oil tank, and is configured so that a connection state and a cut-off state are switched by pilot pressure. The pilot pressure is the hydraulic pressure that stands when the loading device 27 is driven.SELECTED DRAWING: Figure 15

Description

[Technical Field]

[0001] The present invention relates to a refuse collection vehicle. [Background technology]

[0002] The refuse collection vehicle is equipped with a refuse bin for throwing refuse into it, and a refuse storage box connected to the front of the refuse bin for storing the refuse thrown into the refuse bin. The refuse storage box has a discharge opening communicating with the outside of the box, a discharge plate that is movable in the front-rear direction, and a discharge actuator that moves the discharge plate. The refuse bin is movable relative to the refuse storage box to open and close the discharge opening, and is equipped with a loading device that moves the thrown-in refuse into the refuse storage box. The discharge actuator is then driven to move the discharge plate rearward, allowing the stored refuse to be discharged to the outside through the discharge opening of the refuse storage box (see, for example, Patent Document 1).

[0003] In the garbage collection vehicle, garbage placed in the garbage bin is moved to the garbage storage bin by driving the loading device, and then stored there. However, because the discharge plate cannot move forward as the garbage moves, the volume of the garbage storage space cannot be increased depending on the loading situation, making it difficult to use. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-52940 A (see Figures 3 and 4) Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a garbage collection vehicle in which the discharge plate can be moved forward when garbage is loaded. [Means for solving the problem]

[0006] The garbage collection vehicle of the present invention comprises a chassis, a garbage collection box fixed to the chassis, The device comprises a garbage receiving box connected to the garbage receiving box, a discharge plate provided in the garbage receiving box, a discharge actuator connected to the discharge plate, and a hydraulic circuit connected to the discharge actuator so that hydraulic oil can flow in and out, the garbage receiving box has a discharge port communicating with the outside of the box, the garbage receiving box is movable relative to the garbage receiving box to open and close the discharge port, and is equipped with a hydraulically driven loading device that moves garbage into the garbage receiving box, and the discharge plate is movable reciprocatingly within the garbage receiving box between the discharge port side and the back side of the garbage receiving box. The discharge actuator is hydraulically driven and connected to the discharge plate so as to move the discharge plate back and forth, the hydraulic circuit includes at least a switching valve and an oil tank, the switching valve is provided in an oil passage through which hydraulic oil flows to connect the discharge actuator and the oil tank when the discharge plate moves to the back side of the garbage storage box, and is configured to switch between a connected state and a cut-off state by a pilot pressure, and the pilot pressure for switching the switching valve is the hydraulic pressure that is generated when the loading device is operated.

[0007] According to the present invention, the switching valve can be switched to a communicating state by the pilot pressure, which is the pressure that is generated when the loading device is driven, so that the discharge plate can be moved in conjunction with the loading device.

[0008] Furthermore, in the garbage collection vehicle of the present invention, the loading device may be driven by a plurality of loading hydraulic actuators, and the detection position of the pilot pressure may be located closer to the hydraulic source than the plurality of loading hydraulic actuators.

[0009] According to the above configuration, while any one of the loading hydraulic actuators in the loading device is being driven, the switching valve can be switched to the communicating state.

[0010] Further, in the garbage collection vehicle of the present invention, the hydraulic circuit includes a relief valve, The switching valve and the relief valve may be connected in parallel to the oil tank.

[0011] As described above, if the hydraulic circuit receives an external impact while the garbage collection vehicle is traveling, the hydraulic oil can be released through the relief valve, thereby preventing buckling of the discharge actuator and damage to the discharge plate, thereby increasing safety. [Effects of the Invention]

[0012] The present invention can switch the switching valve to a communicating state using pilot pressure, which is the pressure that is generated when the loading device is driven, so that the discharge plate can be moved in conjunction with the loading device.This makes it possible to provide a garbage collection vehicle in which the discharge plate can be moved forward when loading garbage. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a side view of the rear of a garbage collection vehicle equipped with a garbage collection vehicle container lifting device of the present invention. [Figure 2] FIG. 2 is a rear view of the refuse collection vehicle as seen from the rear. [Figure 3] FIG. 2 is a perspective view of a container lifting device for a refuse collection vehicle. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5] FIG. 3 is a cross-sectional view taken along line VV in FIG. [Figure 6A] FIG. 10 is a view showing a state immediately before the container is held by the garbage collection vehicle container lifting device and lifted. [Figure 6B] 6B is a diagram showing the posture of the inverted link in the state of FIG. 6A. FIG. [Figure 7A] FIG. 10 is a view showing a state in which the lifting cylinder is actuated to the extension side to lift the container. [Figure 7B] 7B is a diagram showing the posture of the inverted link in the state of FIG. 7A. FIG. [Figure 8A] FIG. 7B is a diagram showing a state in which the container is further raised than in FIG. 7A. [Figure 8B]8B is a diagram showing the posture of the inverted link in the state of FIG. 8A. FIG. [Figure 9A] FIG. 8B is a diagram showing a state in which the container is further raised than in FIG. 8A. [Figure 9B] 9B is a diagram showing the posture of the inverted link in the state of FIG. 9A. FIG. [Figure 10A] 9B is a diagram showing a state in which the container is further raised from FIG. 9A and the reversing frame is positioned at the maximum raised position. [Figure 10B] 10B is a diagram showing the posture of the inverted link in the state of FIG. 10A. FIG. [Figure 11A] FIG. 10 is a diagram showing a state in which the inversion frame starts to rotate counterclockwise from the maximum raised position. [Figure 11B] 11B is a diagram showing the posture of the inverted link in the state of FIG. 11A. FIG. [Figure 11C] 11B is a diagram showing the attitude of the fall-off prevention member in the state of FIG. 11A. FIG. [Figure 12A] FIG. 11B is a diagram showing a state in which the inverted frame has further rotated counterclockwise from the state in FIG. 11A. [Figure 12B] 12B is a diagram showing the posture of the inverted link in the state of FIG. 12A. FIG. [Figure 12C] 12B is a diagram showing the attitude of the fall-off prevention member in the state of FIG. 12A. FIG. [Figure 13A] FIG. 12B is a diagram showing a state in which the inverted frame has been further rotated counterclockwise from the state in FIG. 12A. [Figure 13B] 13B is a diagram showing the posture of the inverted link in the state of FIG. 13A. FIG. [Figure 13C] 13B is a diagram showing the attitude of the fall-off prevention member in the state of FIG. 13A. FIG. [Figure 14A] This figure shows the state in which the inversion frame has rotated to the maximum rotation position and the garbage in the container can be thrown into the garbage inlet. [Figure 14B] 14B is a diagram showing the posture of the inverted link in the state of FIG. 14A. FIG. [Figure 14C] 14B is a diagram showing the attitude of the fall-off prevention member in the state of FIG. 14A. FIG. [Figure 15] FIG. 1 is an overall side view of a garbage collection vehicle. [Figure 16] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of a garbage collection vehicle will be described with reference to the drawings.

[0015] 1 and 2 show a garbage bin 2 provided at the rear of a garbage collection vehicle 1 that collects garbage such as trash from homes and businesses and transports it to a disposal facility. In the following description, the front-to-rear direction of the garbage collection vehicle 1 will be referred to as the front-to-rear direction, and the width direction of the garbage collection vehicle 1 will be referred to as the left-to-right direction.

[0016] At the rear of the refuse bin 2 of the refuse collection vehicle 1, a refuse collection vehicle container lifting device (hereinafter simply referred to as the lifting device) 3 is arranged, which lifts and lowers a container 6 (see FIG. 6A) described below.

[0017] The lifting device 3 comprises a base 4 arranged at the rear of the periphery of the garbage collection vehicle 1, multiple lifting mechanisms 5,5 (in this embodiment, a pair on the left and right) attached to the base 4 and configured so that their tips move up and down relative to the base end which is the end on the attached side, a container holding section 7 which holds a container 6 that temporarily stores garbage collected by the garbage collection vehicle 1 and is raised and lowered by the lifting mechanisms 5,5, and a container inversion mechanism 8 which tilts the container 6 held by the container holding section 7.

[0018] As described above, since the multiple lifting mechanisms 5, 5 are attached to the vehicle body via a single base 4 that serves as a reference, there is less chance of misalignment of the up-down, front-back, or left-right positions when facing the vehicle body during installation compared to when each of the multiple lifting mechanisms 5, 5 is attached directly to the vehicle body, which makes it easier to attach the container lifting device 3 to the vehicle body and improves workability during installation.

[0019] The base 4 has a cylindrical metal pipe 41 that serves as a horizontal axis extending (in this embodiment, in the left-right direction) along the body of the refuse collection vehicle 1, and this pipe 41 is fixed to the body (refuse bin 2) via two pairs of left and right fixing members 9, 9, which will be described later, and a pair of left and right pivot parts 53, 53, which will be described later. In this embodiment, the case where one base 4 is provided is shown, but it is also possible to provide a plurality of bases (any number of bases equal to or greater than two).

[0020] As described above, since the pivot portions 53, 53 are attached to the horizontal shaft (pipe 41), it is easy to form the base 4 that allows the container lifting device 3 to be easily attached to the vehicle body (garbage bin 2).

[0021] Each lifting mechanism 5 is composed of a quadruple parallel link mechanism and includes a pair of parallel upper and lower lifting arms 51, 52 that rise and fall relative to the vehicle body (garbage bin 2), a pivot part 53 that pivotally supports each of the pair of upper and lower lifting arms 51, 52 so that they can rotate about a horizontal axis at their base ends, and a lifting frame 54 to which the tips of the lifting arms 51, 52 are pivotally connected. The upper lifting arm 51 is composed of two arms 51A, 51A arranged at a distance in the left-right direction, and the lower lifting arm 52, like the upper lifting arm 51, is also composed of two arms 52A, 52A arranged at a distance in the left-right direction.

[0022] As shown in FIGS. 1 and 3, the pivotal support portions 53 are attached to both ends of the pipe 41 and fixed by welding to the left and right side walls 2A of the refuse bin 2 of the refuse collection vehicle 1. Specifically, each pivotal support portion 53 includes a pair of left and right pivotal support body portions 531 that are long in the vertical direction, and a fixed portion 532 that is connected to the pivotal support body portions 531 and fixed to the vehicle body (the refuse bin 2) by welding. The fixed portion 532 includes an inclined plate portion 532A that is positioned more outward toward the rear, and an elliptical through-hole 532K is formed in the inclined plate portion 532A. A support member 13 is welded to the upper end of the through-hole 532K for inserting and supporting a hydraulic hose (not shown) that supplies hydraulic oil from an oil tank located elsewhere to cylinders 25, 31, 32, and 33 (described below) provided inside the refuse collection vehicle 1. This support member 13 is made by bending a round bar with a circular cross section into an approximately circular shape so that it functions as a guide member to prevent the hydraulic hose from being worn down by sliding against the hydraulic hose that moves back and forth due to the extension and contraction of the cylinders 32, 31, 33, and 25.

[0023] As shown in FIG. 1, each pivot support body 531 has four circular through-holes 531A, 531B, 531C, and 531D formed at intervals in the vertical direction. The base end of the upper lifting arm 51 is pivotally connected to the first through-hole 531A (the first from the top) via a shaft 51a. The base end of the cylinder tube 16A of the telescopic cylinder 16 (described later) is pivotally connected to the second through-hole 531B (the second from the top) via a shaft 16C. One end of the pipe 41 is passed through the third through-hole 531C (the third from the top) and fixed by welding. The third through-hole 531C forms an abutment that abuts against the pipe 41 in a direction along a plane perpendicular to the central axis of the pipe 41. The base end of the lower lifting arm 52 is pivotally connected to the fourth through-hole 531D (the fourth from the top) via a shaft 52a.

[0024] As described above, the pivot portions 53, 53 can be positioned in the vertical and front-to-rear directions by the abutment between the abutment portion (the inner surface of the third through hole 531C) of the pivot portions 53, 53 and the horizontal axis (the outer surface of the pipe 41), but it is also possible to position the pivot portions 53, 53 only in the vertical direction or only in the front-to-rear direction.

[0025] As shown in Figures 2 and 3, two pairs of left and right fixing members 9, 9 are arranged between the left and right pivotal support members 53, 53 and fixed to the vehicle body (garbage bin 2) by welding. The pair of left and right fixing members 9, 9 are configured in a plate shape. As shown in Figure 4, each fixing member 9 has an upper end 9A, a middle portion 9B extending downward from the lower end of the upper end 9A, and a lower end 9C extending forward from the lower end of the middle portion 9B. Two connecting plates 10, 11 abut against the inner surface of the upper end 9A and are integrated with the left and right ends of the connecting plates 10, 11 by welding. A through hole 9K is formed in the lower end 9C, through which a pipe 41 passes and is fixed by welding. The pipe 41 is fixed to the vehicle body (garbage bin 2) via the two sets of fixing members 9, 9, 9, 9.

[0026] The upper end 9A is formed to protrude rearward in an arc shape, and the top 9a has a horizontal surface. The middle portion 9B is formed so that the front and rear end faces follow the vertical direction, and the front end face 9b is welded in a state of abutting against a rear plate portion 12B that follows the vertical direction of a horizontal frame 12 that is provided at the lower rear end of the garbage bin 2 and has a substantially pentagonal cross section extending in the left-right direction. The lower end 9C includes a front plate portion 9D located on the front side and abutting against and welded to a diagonal plate portion 12F at the lower front side of the horizontal frame 12, and a rear plate portion 9E that extends rearward from the rear end of the front plate portion 9D and abuts against and welded to a horizontal plate portion 12A at the lower rear side of the horizontal frame 12.

[0027] Of the two connecting plates 10, 11, one connecting plate 10 is composed of a horizontally oriented first connecting plate extending in the front-to-rear direction at the vertically intermediate portion of the upper end portion 9A, and the other connecting plate 11 is composed of a second connecting plate extending obliquely upward and forward from approximately the center in the front-to-rear direction of the first connecting plate 10. The first connecting plate 10 functions as a blocking member that blocks the movement of the inversion link 82, which will be described later, in the extension direction.

[0028] As will be described later, a guide member 15 is attached to the upper end of the fixed member 9 for guiding trash discharged from the opening 6A of the tilted container 6 to the drop-in opening 2K of the trash bin 2. The guide member 15 is made of metal and configured as a plate-shaped table. The guide member 15 has a substantially triangular upper end 15A that abuts against the upper end 9A of the fixed member 9 from above, and a lower end 15B that bends diagonally downward and forward from the front lower end of the upper end 15A and abuts against the horizontal frame 12. Therefore, trash discharged from the opening 6A of the tilted container 6 can be guided by the upper surface of the guide member 15 and reliably deposited into the trash bin 2.

[0029] 2 and 3, the lifting frame 54 is pivotally connected to the tip ends of a pair of upper and lower lifting arms 51, 52. Specifically, the lifting frame 54 includes a pair of left and right plate-shaped vertical members 541, 541 arranged at both left and right ends, a first pipe 542 that is long in the left-right direction and penetrates the upper ends of the vertical members 541, 541, a second pipe 543 that is long in the left-right direction and penetrates approximately the center of the vertical members 541, 541, a third pipe 544 that connects the lower ends of the vertical members 541, 541, and a plate-shaped connecting member 545 that is located inside the left-right direction of the vertical members 541, 541 and through which the first pipe 542 and the second pipe 543 pass and are fixed by welding. Each of the left and right ends of the first pipe 542 penetrates the outer vertical member 541 and protrudes outward, and the protruding portion penetrates the tip end of the upper lifting arm 51 and is rotatably connected thereto. Furthermore, both left and right ends of the third pipe 544 penetrate the outer vertical members 541 in the left-right direction and protrude outward, and the protruding portions penetrate the tip ends of the lower lifting arms 52 and are rotatably connected thereto. Therefore, as the lifting arms 51, 52 swing due to the extension and contraction of the telescopic cylinder 16 (described later), the lifting frames 54, 54 rise and fall while maintaining their up-and-down positions.

[0030] 1 and 3, the upper lifting arm 51 includes a first extension portion 511 that extends further toward the tip end from the portion where the tip end of the lifting arm 51 is pivotally supported by the vertical member 541, and a second extension portion 512 that extends 90° downward from the extension end of the first extension portion 511. Between the second extension portion 512 of the upper lifting arm 51 and approximately the center in the vertical direction of the pivot support portion 53, there is provided a telescopic cylinder 16 that serves as a drive source (actuator) that generates a drive force for swinging the upper lifting arm 51. By extending the telescopic cylinder 16, the lifting arms 51, 52 can be moved upward, and by shortening the telescopic cylinder 16, the lifting arms 51, 52 can be moved downward.

[0031] 6A, container 6 includes a cylindrical container body 61 that is generally rectangular in plan view and has an open upper end and a bottom, a flange portion 62 that extends forward from one side (front side) of the upper end of container body 61, and a hanging portion 63 that extends downward from the outer peripheral edge of flange portion 62 and can be engaged with and disengaged by claws 7A, which will be described later. Hanging portion 63 is formed in a stepped shape.

[0032] 3, the container holding portion 7 is composed of claws 7A provided at the rear end of a horizontal plate portion 811b of an inverting frame main body 811 of an inverting frame 81, which will be described later. The claws 7A are made up of a plurality (eight in this embodiment) of claws 7A extending upward at intervals in the left-right direction of the horizontal plate portion 811b, and each claw 7A is formed in the shape of a rectangular plate. The container 6 can be held by engaging the front hanging portion 63 of the container 6 inside these multiple claws 7A.

[0033] The container inverting mechanism 8 is a mechanism that changes the orientation of the opening 6A of the container 6 by tilting the container 6 held by the container holding part 7. Specifically, as shown in FIG. 3, the container inverting mechanism 8 includes a metal inverting frame 81 and a metal inverting link 82.

[0034] The inverting frame 81 is rotatably attached to the lifting frame 54 that constitutes the lifting mechanism 5, and rotates relative to the lifting mechanism 5 by receiving a driving force transmitted from the drive source (telescopic cylinder 16) of the lifting mechanism 5. Specifically, the inverting frame 81 includes an inverting frame main body 811 that is long in the left-right direction, and a pair of left and right vertical brackets 812, 812 that are long in the up-down direction and fixed by welding to both left and right end portions of the inverting frame main body 811. The inverting frame main body 811 is configured in a generally L-shape in side view, having a vertical plate portion 811a that extends in the up-down direction, and a horizontal plate portion 811b that is bent rearward from the lower end of the vertical plate portion 811a.

[0035] As described above, by providing the reversing frame 81 that rotates relative to the lifting mechanism 5 upon receiving a driving force transmitted from the driving source (telescopic cylinder 16) of the lifting mechanism 5, the driving source (telescopic cylinder 16) of the lifting mechanism 5 can also serve as the driving source for rotating the reversing frame 81, thereby eliminating the need for a dedicated driving source (actuator) for reversing.

[0036] As shown in FIG. 4, each vertical bracket 812 is supported by a first pipe 542 of the lifting frame 54 at a position slightly above the vertical center and toward the front so as to be rotatable about the left-right axis X1. Each vertical bracket 812 has an upper portion 812A that is larger in the front-to-rear direction than the other portions, and a lower portion 812B that has a cutout at the front end so that the front-to-rear direction dimension is smaller than that of the upper portion 812A. By providing this lower portion 812B, the lower portion 812B of the vertical bracket 812 supported by the first pipe 542 does not interfere with the second pipe 543 and the third pipe 544 of the lifting frame 54. Plate-shaped blocking members 811A (see FIG. 3) that are generally triangular in side view are fixed to both left and right ends of the reversing frame main body 811. For example, even if the container 6 unexpectedly moves left or right when being raised or lowered on a slope, the left and right ends of the container 6 abut against the blocking members 811A or 811A, thereby preventing further left or right movement of the container 6.

[0037] As shown in FIG. 3, the lower ends of the left and right vertical brackets 812, 812, 812, 812 are connected to a connecting pipe 813 by passing through it, and a cushion rubber 814 that is long in the left-right direction and acts as a buffer when the front surface of the container 6 abuts against it is attached to the rear surface of the connecting pipe 813 via an attachment member 815.

[0038] 2, 3, and 4, a pair of left and right inversion links 82 are provided, and one end of each inversion link 82 is rotatably connected to the fixed members 9, 9 of the base 4, and the other end is rotatably connected to the inversion frame 81. Specifically, each inversion link 82 is configured in an elongated plate shape and includes a pair of left and right first links 82A, 82A (see FIG. 2) pivotally connected between upper end portions 9A, 9A of the fixed members 9, 9, and a second link 82B pivotally connected while sandwiched between the tip ends of the first links 82A, 82A and having a dimension longer than the first link 82A. The tip end of the second link 82B is pivotally supported between left and right vertical brackets 812, 812 of the inversion frame 81. In this way, by constructing the inversion link 82 from the first links 82A, 82A and the second link 82B, the linear distance L (see Figure 4) between the connection position with the fixed member 9 at one end (base end) of the first links 82A, 82A and the connection position with the inversion frame 81 at the other end (tip end) of the second link 82B is configured to change, and rotation of the inversion frame 81 is restricted (not caused) or allowed depending on the change in the linear distance L.

[0039] As described above, the reversing frame 81 is attached to the lifting mechanisms 5, 5, and the reversing link 82 is connected to the base 4, so even if the reversing frame 81 and the reversing link 82 are provided, it is easy to attach the container lifting device 3 to the vehicle body. In addition, the reversing link 82 is configured to change between an extension / contraction stage (see FIGS. 6A to 9A) in which the linear distance L changes, and a maximum extension stage (see FIGS. 10A to 14A) in which the linear distance L is at its maximum. This allows the operation of the reversing frame 81 to be changed at each stage during the lifting / lowering of the lifting mechanisms 5, 5, that is, the reversing frame 81 can be changed from lifting / lowering to rotating.

[0040] Furthermore, when the lifting frame 54 rises from the lowest end of its movement range to an intermediate position (see FIGS. 6A to 9A), the inverting links 82 are in the extension / contraction stage, which limits (does not cause) the rotation of the inverting frame 81, thereby lifting the container 6 without rotating it, and when the lifting frame 54 rises above the intermediate position (see FIGS. 10A to 14A), the inverting links 82 transition to the maximum extension stage, thereby rotating the container 6. In this way, when the lifting frame 54 rises above the intermediate position, the inverting links 82 transition to the maximum extension stage, which changes the operation of the inverting frame 81 from lifting to rotating it.

[0041] The inversion frame 81 is also provided with a fall (detachment) prevention member 17 to prevent the hanging portion 63 of the container 6, which is engaged with the claws 7A of the inversion frame 81, from being released from the engagement and the container 6 from falling (detaching) from the claws 7A when the container 6 tilts.

[0042] 3 and 5, the fall-off prevention member 17 includes a contact portion 17A that is elongated in the left-right direction and contacts the flange portion 62 (see FIG. 6A) of the container 6, and a pair of left and right brackets 17B, 17B that are attached to two left and right locations of the contact portion 17A and extend diagonally downward and forward. Approximately the longitudinal center of each bracket 17B, 17B is attached to a plate-shaped support member 18 that is attached to the inversion frame 81 so as to extend diagonally upward and forward, so as to be rotatable about a left-right axis X2. The lower end of each bracket 17B, 17B is pivotally connected to a tongue 541A provided at the upper end of a vertical member 541 of the lifting frame 54 and extending forward, by a plate-shaped connecting member 19. When the lifting frame 54 rises above a predetermined raised position, the fall-off prevention member 17 rotates counterclockwise and contacts the flange portion 62 of the container 6.

[0043] The following describes the procedure for raising and lowering the container 6 using the lifting device 3 configured as described above, thereby dumping the garbage inside the container 6 into the garbage collection vehicle 1. Note that, because the movement (posture) of the reversing link 82 cannot be grasped from the side views of Figures 6A, 7A, 8A, 9A, and 10A, side views in which the lifting device 3 is cut at a position where the reversing link 82 can be seen have been added to Figures 6B, 7B, 8B, 9B, and 10B, respectively.

[0044] In Fig. 6A, the container 6 is set on the lifting device 3 by engaging the hanging portion 63 of the container 6 with the claws 7A of the lifting device 3 which is in the lowered position. In Fig. 6B, the container 6 is at the same height position as in Fig. 6A, and the postures of the first links 82A, 82A and the second link 82B change in accordance with the linear distance L between the connection position of one end (base end) of the first links 82A, 82A of the reversing link 82 with the base and the connection position of the other end (tip end) of the second link 82B of the reversing link 82 with the vertical bracket 812 of the reversing frame 81.

[0045] From the set state shown in Figure 6A, by operating a switch (not shown), the telescopic cylinder 16 is operated to the extension side. As a result, as shown in Figure 7A, the lifting mechanism 5 rises, and the container 6 rises. Figure 7B shows the same raised position as in Figure 7A. As the lifting mechanism 5 rises, the other end (tip) of the second link 82B of the reversing link 82 rises, and the connection position of the other end (tip) of the second link 82B with the vertical bracket 812 of the reversing frame 81 approaches the connection position of the base end of one end (base end) of the first links 82A, 82A of the reversing link 82. As a result, the linear distance L changes, and the posture of the second link 82B changes in accordance with this linear distance L.

[0046] FIG. 8A shows a state in which the lifting mechanism 5 is further elevated from the state shown in FIG. 7A due to the extension of the telescopic cylinder 16, and the container 6 is elevated. FIG. 8B shows the same elevated position as in FIG. 8A, and the postures of the first links 82A, 82A and the second link 82B change in accordance with the linear distance L.

[0047] FIG. 9A shows the state in which the lifting mechanism 5 is further elevated from the state in FIG. 8A due to the extension of the telescopic cylinder 16, and the container 6 is elevated. FIG. 9B shows the same elevated position as in FIG. 9A. As the lifting mechanism 5 is elevated, the connection position of the other end (tip) of the second link 82B of the reversing link 82 with the vertical bracket 812 of the reversing frame 81 moves away from the connection position of the base end (base end) of the first link 82A of the reversing link 82 with the base. This changes the linear distance L, and the postures of the first links 82A and the second link 82B change in accordance with this linear distance L. The first links 82A and 82A shown in FIG. 8B are pulled by the second link 82B and rotate counterclockwise, resulting in the first links 82A and the second link 82B taking the posture shown in FIG. 9B.

[0048] FIG. 10A shows a state in which the lifting mechanism 5 is further elevated from the state shown in FIG. 9A due to the extension of the telescopic cylinder 16, causing the container 6 to rise. FIG. 10B shows the same elevated position as in FIG. 10A. As the lifting mechanism 5 rises, the connection position between the other end (tip) of the second link 82B of the reversing link 82 and the vertical bracket 812 of the reversing frame 81 becomes further away from the connection position between the base end (base end) of one end of the first links 82A of the reversing link 82 and the base. This changes the linear distance L, and the postures of the first links 82A and the second link 82B change in accordance with this linear distance L. The first links 82A and 82A shown in FIG. 10B are pulled by the second link 82B and rotate counterclockwise, assuming the posture shown in FIG. 10B. At this time, the first links 82A, 82A abut against the horizontal plate portion 811b, restricting the counterclockwise rotation of the first links 82A, 82A, and therefore, when the lifting mechanism 5 rises further, the second link 82B rotates counterclockwise around the connection portion 20 with the first links 82A, 82A, and the vertical bracket 812 of the reversing frame 81 begins to tilt forward. As the vertical bracket 812 of the reversing frame 81 begins to tilt forward, the attitude of the fall-prevention member 17 also changes, and therefore side views in which the lifting device 3 is cut at a position where the fall-prevention member 17 can be seen have been added to each of Figures 11C, 12C, 13C, and 14C.

[0049] 10A and 10B, as described above, the first link 82A abuts against the connecting plate 10, restricting the counterclockwise rotation of the first links 82A, 82A, and therefore, when the lifting mechanism 5 further rises, the second link 82B rotates counterclockwise about the connecting portion 20 with the first links 82A, 82A, and the vertical bracket 812 of the reversing frame 81 and the container 6 held by the vertical bracket 812 start to assume a forward tilting position (see FIGS. 11A and 11B). At this time, as the vertical bracket 812 of the reversing frame 81 assumes a forward tilting position, the connecting member 19, by which the falling-off prevention member 17 is connected to the lifting frame 54, also starts to assume a forward tilting position (see FIG. 11C).

[0050] When the lifting mechanism 5 is further elevated from the state shown in Fig. 11A due to the extension of the telescopic cylinder 16, the second link 82B further rotates counterclockwise around the connecting portion 20 with the first links 82A, 82A, and as shown in Figs. 12A and 12B, the vertical bracket 812 of the reversing frame 81 and the container 6 further tilt forward. At this time, the connecting member 19 tilts further forward compared to Fig. 11C, and the abutting portion 17A of the fall-off prevention member 17 approaches the flange portion 62 of the container 6 (see Fig. 12C).

[0051] When the lifting mechanism 5 is further elevated from the state shown in FIG. 12A due to the extension of the telescopic cylinder 16, the second link 82B further rotates counterclockwise around the connecting portion 20 with the first links 82A, 82A, and as shown in FIGS. 13A and 13B, the vertical bracket 812 of the reversing frame 81 and the container 6 assume a further forward-leaning posture, i.e., an inclined posture in which the upper end of the container 6 is positioned lower than the lower end. At this time, the connecting member 19 assumes a further forward-leaning posture compared to FIG. 12C, and the abutting portion 17A of the fall-off prevention member 17 rotates to a position where it abuts against the flange portion 62 of the container 6 (see FIG. 13C). This prevents the container 6 from moving forward and prevents the container 6 from falling off the claws 7A.

[0052] When the lifting mechanism 5 is further raised from the state shown in Fig. 13A due to the extension of the telescopic cylinder 16, the second link 82B further rotates counterclockwise around the connecting portion 20 with the first links 82A, 82A, and as shown in Figs. 14A and 14B, the vertical bracket 812 of the reversing frame 81 and the container 6 further tilt forward, causing the garbage in the container 6 to move under its own weight into the garbage bin 2. At this time, the connecting member 19 tilts further forward compared to Fig. 13C, and the abutting portion 17A of the fall-off prevention member 17 maintains a state of abutting against the flange portion 62 of the container 6 (see Fig. 14C). This prevents the container 6 from moving forward and prevents the container 6 from falling off the claws 7A.

[0053] After the garbage in the container 6 has been dumped into the garbage dump box 2, the lifting device 3 is operated in the opposite direction to the above-mentioned operation by operating a switch (not shown), thereby returning it to the state shown in Figure 6A, and then the container 6 is removed from the claws 7A and returned to the specified position, completing the work.

[0054] The refuse collection vehicle 1 will now be described in further detail. As shown in Figure 15, the refuse collection vehicle 1 is equipped with a driver's seat 21, a refuse collection box 23 fixed to a chassis 22 behind the driver's seat 21, the above-mentioned refuse insertion box 2 provided adjacent to the rear side of the refuse collection box 23, a discharge plate 24 provided inside the refuse collection box 23, a discharge actuator 25 connected to the discharge plate 24, and a hydraulic circuit 26 (see Figure 16) connected to the discharge actuator 25 so that hydraulic oil can flow in and out. The refuse collection box 23 is equipped with a discharge port 23A that communicates with the outside of the box.

[0055] The garbage bin 2 is configured to be rotatable about a left-right axis X3 at the upper end relative to the garbage collection box 23 so as to open and close the discharge outlet 23A. The two-dot chain line in Fig. 15 indicates the rotated position of the garbage bin 2 when the discharge outlet 23A is open, and the solid line in Fig. 15 indicates the rotated position of the garbage bin 2 when the discharge outlet 23A is closed. The garbage bin 2 also has a hydraulically driven loading device 27 that moves the garbage that has been put into it into the garbage collection box 23.

[0056] The loading device 27 includes a slider 28 and a push plate 29 rotatably attached to the lower end of the slider 28 via a pin P. The slider 28 moves along guide rails 30 provided on the left and right side walls 2A, 2A of the garbage bin 2. A pair of push cylinders 31 is attached between the slider 28 and the left and right side walls 2A, 2A on both the left and right sides of the garbage bin 2. In addition, a pair of press cylinders 32 is attached between the push plate 29 and the slider 28. The push cylinders 31 and the press cylinders 32 are loading hydraulic actuators in the loading device 27.

[0057] The operation of the loading device 27 will be described. First, the press cylinder 32 is driven to contract from the position shown by the solid line in Fig. 15, thereby rotating the push plate 29 counterclockwise and reversing the push plate 29 (reversal process). Next, the push cylinder 31 is driven to contract, causing both the slider 28 and the push plate 29 to descend diagonally backward, and the garbage thrown from the throw-in port 2K is compressed by the push plate 29 (primary compression process). Then, the press cylinder 32 is driven to extend, thereby rotating the push plate 29 clockwise and performing a secondary compression of the garbage (secondary compression process).

[0058] Next, from the state shown by the two-dot chain line in Fig. 15, the push cylinder 31 is extended to raise the slider 28 and the push plate 29 diagonally forward to the state shown by the solid line in Fig. 15, and the secondarily compressed garbage is pushed into the garbage storage box 23 (pushing process). In this way, the loading device 27 can load the garbage thrown into the garbage drop box 2 into the garbage storage box 23 by performing a loading process cycle consisting of the reversing process, the primary compression process, the secondary compression process, and the pushing process.

[0059] The discharge plate 24 is provided in the garbage collection box 23 so as to be able to move back and forth between the discharge port 23A side and the rear side (front side of the vehicle) of the garbage collection box 23. The discharge actuator 25 is hydraulically driven and is composed of a telescopic discharge cylinder connected to the discharge plate 24 so as to move the discharge plate 24 back and forth. The extension and contraction drive of the discharge cylinder 25 moves between the rearmost position shown by the solid line in FIG. 15 and the frontmost position shown by the two-dot chain line in FIG. 15.

[0060] When the garbage collection box 23 is empty, the discharge plate 24 is in its rearmost position, and garbage loaded into the garbage collection box 23 by the push plate 29 is compressed between the push plate 29 and the discharge plate 24. When either the press cylinder 32 or the push cylinder 31, which are loading hydraulic actuators in the loading device 27, is driven, pressure is generated to discharge hydraulic oil from the discharge cylinder 25 via a second pilot check valve 43B (described later), gradually shortening the discharge cylinder 25 and moving the discharge plate 24 forward. In addition, when the garbage drop box 2 is rotated upward by extending the pair of swing cylinders 33 shown in FIG. 16 (see the two-dot chain line in FIG. 15), the discharge cylinder 25 is extended to move the discharge plate 24 rearward (see the solid line in FIG. 15), and the garbage stored in the garbage collection box 23 can be discharged to the outside through the discharge port 23A.

[0061] 16 shows hydraulic circuit 26, which connects various actuators, namely press cylinder 32, push cylinder 31, discharge cylinder 25, swing cylinder 33, and tailgate lock cylinder 44, so that hydraulic oil can flow in and out. This hydraulic circuit is composed of an oil tank 34, a hydraulic pump 35 (a hydraulic pressure source), relief valve 36A, counterbalance valve 36B, counterbalance valve 36C, press cylinder selector valve 37, push cylinder selector valve 38, swing cylinder selector valve 39, discharge cylinder selector valve 40, tailgate lock selector valve 42, first pilot check valve 43A, second pilot check valve 43B, and tailgate lock cylinder 44, all connected as shown. From the upstream side of hydraulic pump 35, the tailgate lock selector valve 42, discharge cylinder selector valve 40, swing cylinder selector valve 39, push cylinder selector valve 38, and press cylinder selector valve 37 are connected to hydraulic pump 35 in this order. The press cylinder switching valve 37 and the push cylinder switching valve 38 are a loading hydraulic pressure switching valve 49 in the loading device.

[0062] The first pilot check valve 43A is provided in a second oil passage 46 through which hydraulic oil flows to connect the discharge cylinder 25 and the oil tank 34 when the discharge plate 24 moves to the rear of the trash collection box 23. The first pilot check valve 43A is a switching valve configured to switch between a connected state and a blocked state depending on a pilot pressure described below. The second oil passage 46 branches off from a first oil passage 45 through which hydraulic oil is supplied from the discharge cylinder switching valve 40 to the extension side of the discharge cylinder 25, and is configured as an oil passage for returning hydraulic oil to the oil tank 34. The first pilot check valve 43A is connected to a pilot oil passage 48 that guides, as pilot pressure, the pressure generated in a third oil passage 47 through which hydraulic oil supplied from the hydraulic pump 35 is supplied to the press cylinder switching valve 37 or the push cylinder switching valve 38. The pilot oil passage 48 is connected to the hydraulic pump 35 side (upstream) of the loading hydraulic pressure switching valve 49. Therefore, when the press cylinder 32 or the push cylinder 31 is not driven (for example, when the vehicle is running), no pressure is applied to the third oil passage 47, and the first pilot check valve 43A is closed, preventing hydraulic oil from moving from the second oil passage 46 to the oil tank 34. In contrast, when the press cylinder 32 or the push cylinder 31 is driven (moving debris to the debris collection box 23), pressure is applied to the third oil passage 47. The pilot pressure generated by this pressure acts on the first pilot check valve 43A through the pilot oil passage 48, opening the first pilot check valve 43A and establishing a communication state, allowing extension-side hydraulic oil accumulated in the discharge cylinder 25 to flow from the second oil passage 46 to the oil tank 34. As a result, the discharge plate 24 receives pressure equal to or greater than a predetermined pressure from the debris moving to the debris collection box 23, causing the discharge plate 24 to move forward. The detection position of the pilot pressure is closer to the hydraulic source (hydraulic pump 35) than the plurality of loading hydraulic actuators. Even if the hydraulic pump 35 is being driven (discharging), when the loading hydraulic pressure changeover valve 49 is in the loading stop position, the hydraulic oil simply passes through and is returned to the oil tank 34. As a result, no pressure is generated in the third oil passage 47, and the first pilot check valve 43A remains closed.

[0063] In Figure 16, when no signal is received from a switch (not shown), the press cylinder selector valve 37, push cylinder selector valve 38, swing cylinder selector valve 39, discharge cylinder selector valve 40, and tailgate lock selector valve 42 are located in a neutral position where the hydraulic oil from the hydraulic pump 35 is not supplied to the cylinder by springs provided on both sides. Each selector valve is then moved to either the left or right in Figure 16 and switched in response to a signal from a switch (not shown).

[0064] The press cylinder selector valve 37 or the push cylinder selector valve 38 is switched from the neutral position to supply hydraulic oil from the hydraulic pump 35 to the press cylinder 32 or the push cylinder 31, thereby driving the press cylinder 32 or the push cylinder 31 to extend or retract, and thereby operating the loading device 27. The discharge cylinder selector valve 40 is switched from the neutral position to supply hydraulic oil from the hydraulic pump 35 to the discharge cylinder 25, thereby driving the discharge cylinder 25 to extend or retract, and thereby moving the discharge plate 24 back and forth. The swing cylinder selector valve 39 is switched from the neutral position to supply hydraulic oil from the hydraulic pump 35 to the swing cylinder 33, thereby driving the swing cylinder 33 to extend or retract, and thereby rotating the garbage bin 2 up and down. The tailgate lock selector valve 42 is switched from the neutral position to supply hydraulic oil from the hydraulic pump 35 to the tailgate lock cylinder 44, thereby driving the tailgate lock cylinder 44 to extend or retract, and thereby locking or unlocking the tailgate lock.

[0065] When a signal from a switch (not shown) moves the press cylinder switching valve 37 to the right, the press cylinder 32 is retracted (reversal process). When a signal from a switch (not shown) moves the press cylinder switching valve 37 to the left, the press cylinder 32 is extended (secondary compression process). When a signal from a switch (not shown) moves the push cylinder switching valve 38 to the right, the push cylinder 31 is retracted (primary compression process). When a signal from a switch (not shown) moves the push cylinder switching valve 38 to the left, the push cylinder 31 is extended (pushing process).

[0066] When the discharge cylinder switching valve 40 moves to the left in response to a signal from a switch (not shown), the discharge cylinder 25 extends. When the discharge cylinder switching valve 40 moves to the right in response to a signal from a switch (not shown), the discharge cylinder 25 contracts.

[0067] When the loading device 27 pushes garbage into the garbage collection box 23, either the press cylinder 32 or the push cylinder 31, which are loading hydraulic actuators, are driven. This drive compresses the garbage between the push plate 29 and the discharge plate 24, but the pilot pressure, which is the pressure created when the press cylinder 32 or the push cylinder 31 is driven, moves the hydraulic oil stored on the extension side of the discharge cylinder 25 to the oil tank 34, allowing the discharge plate 24 to move forward. After the loading operation by the loading device 27 is completed and the garbage collection vehicle 1 is being moved to the next collection site, the press cylinder 32 and the push cylinder 31 are not driven, so the first pilot check valve 43A remains closed, preventing the discharge plate 24 from moving forward.

[0068] By connecting the first pilot check valve 43A and the counterbalance valve 36B in parallel to the oil tank 34, if the hydraulic circuit 26 receives an external impact while the garbage collection vehicle is traveling, hydraulic oil can be released from the counterbalance valve 36B, thereby preventing buckling of the discharge actuator 25 and damage to the discharge plate 24 due to abnormally high pressure, and improving safety.

[0069] A relief valve may be used as the switching valve. In this case, if the pressure of the relief valve is set to a high pressure, the forward movement of the discharge plate 24 during travel can be restricted. However, if the discharge plate 24 is pushed by the garbage during loading, it will not move forward until the same high pressure as the relief valve is applied, which may result in damage to the discharge plate 24. On the other hand, if the pressure of the relief valve is set to a low pressure, the discharge plate 24 will easily move forward during travel (for example, it will move every time the brakes are applied, which may cause travel disruption in some cases). Furthermore, the sliding resistance of the discharge plate 24 during movement varies from plate to plate due to manufacturing errors. Setting the pressure of the relief valve is tedious, making it difficult to actually use a relief valve. Therefore, in this embodiment, a pilot check valve linked to the loading device is used.

[0070] The present invention can be modified in various ways without departing from the spirit and scope of the invention. The specific configurations of the various parts are not limited to the above-described embodiments.

[0071] In the above embodiment, two lifting mechanisms 5, 5 are provided, but any number of lifting mechanisms, such as one or three or more, may be provided. Each lifting mechanism does not need to have two lifting arms that are parallel to each other, and may be configured with a single lifting arm. Furthermore, multiple lifting mechanisms may be provided biased to one side in the left-right direction.

[0072] In the above embodiment, the horizontal axis is a cylindrical pipe 41, but it may be a shaft member with a solid interior. The external shape may be any shape other than a circle, such as a polygonal shape such as a triangle or a square, a semicircular shape, an elliptical shape, or the like.

[0073] In addition, in the above embodiment, a through hole is shown as the abutment portion for the horizontal axis, but it may also be configured with a male-female mating structure, for example, by forming a convex portion on one side and a concave portion on the other side that fits into the convex portion.

[0074] Furthermore, in the above embodiment, the container lifting device for a refuse collection vehicle is disposed at the rear of the vehicle body, but it may be disposed at one of the left and right sides of the vehicle body or at the front of the vehicle body.

[0075] In addition, in the above embodiment, two pairs of left and right fixing members 9, 9 and a pair of left and right pivot members 53, 53 were provided to fix the base (pipe 41) to the vehicle body (garbage bin 2), but the two pairs of left and right fixing members 9, 9 may be omitted.

[0076] In addition, in the above embodiment, the reversing link 82 is composed of the first links 82A, 82A and the second link 82B, but it may be composed of a single plate member having a long hole formed therein that can absorb changes in the linear distance L. Also, it may have a form different from that of the above embodiment, for example, a link whose length changes.

[0077] In addition, in the above embodiment, the first connecting plate 10 functions as a blocking member that blocks the movement of the reversing link 82 toward the extension side, but the first connecting plate 10 may be omitted. In this case, the container 6 is configured to rotate after the reversing link 82 has shifted to the maximum extension stage.

[0078] Furthermore, in the above embodiment, a pilot check valve is used as the switching valve, but a directional switching valve that switches the flow direction of the hydraulic oil by pilot pressure may also be used.

[0079] In addition, in the above embodiment, when a heavy object is lowered using a cylinder, counterbalance valves 36B and 36C are used to limit the speed at which the cylinder descends so that the cylinder does not descend under its own weight, but general-purpose relief valves may also be used.

[0080] Furthermore, in the above embodiment, the loading device 27 includes the slider 28 and the push plate 29, but other loading devices (for example, a rotary plate type) may also be used. [Explanation of symbols]

[0081] 1...garbage collection vehicle, 2...garbage dump box, 2A...side wall, 2K...drop inlet, 3...lifting device, 4...base, 5...lifting mechanism, 6...container, 6A...opening, 7...container holding section, 7A...claws, 8...container inversion mechanism, 9...fixing member, 9A...upper end, 9B...middle section, 9C...lower end, 9D...front plate section, 9E...rear plate section, 9K...through hole, 9a...top, 9b...front end surface, 10, 11...connecting plate, 12...horizontal frame, 12A...horizontal plate section, 12B...rear plate section, 12F...diagonal plate section, 13...support member , 15...guide member, 15A...upper end, 15B...lower end, 16...telescopic cylinder, 16A...cylinder tube, 16C...shaft, 17...fall-off prevention member, 17A...contact portion, 17B...bracket, 18...support member, 19...connecting member, 20...connecting portion, 21...driver's seat, 22...chassis, 23...garbage collection box, 23A...discharge port, 24...discharge plate, 25...discharge actuator (discharge cylinder), 26...hydraulic circuit, 27...loading device, 28...slider, 29...push plate, 30... Guide rail, 31...push cylinder, 32...press cylinder, 33...swing cylinder, 34...oil tank, 35...hydraulic pump, 36A...relief valve, 36B, 36C...counterbalance valve, 37...switching valve for press cylinder, 38...switching valve for push cylinder, 39...switching valve for swing cylinder, 40...switching valve for discharge cylinder, 41...pipe (horizontal shaft), 42...switching valve for tailgate lock, 43A, 43B...pilot check valve, 44... tailgate lock cylinder, 45... first oil passage, 46... second oil passage, 47... third oil passage, 48... pilot oil passage, 49... loading hydraulic pressure switching valve, 51, 52... lifting arm, 51a, 52a... shaft, 51A, 52A... arm, 53... pivot part, 54... lifting frame, 61... container body, 62... flange part, 63... hanging part, 81... inversion frame, 82... inversion link, 82A... first link, 82B... second link, 531... pivot part body, 531A, 531B, 531C,531D...through hole, 532...fixing portion, 532A...inclined plate portion, 532K...through hole, 541...vertical member, 541A...tongue, 542...first pipe, 543...second pipe, 544...third pipe, 545...connecting member, 811...inverted frame body, 811A...blocking member, 811a...vertical plate portion, 811b...horizontal plate portion, 812...vertical bracket, 812A...upper portion, 812B...lower portion, 813...connecting pipe, 814...cushion rubber, 815...mounting member, L...linear distance, P...pin, X1, X2, X3...left and right axis,

Claims

1. The chassis and a trash collection box fixed to the chassis; a trash container connected to the trash container; a discharge plate provided in the trash storage box; an ejection actuator connected to the ejection plate; a hydraulic circuit connected to the discharge actuator so that hydraulic oil can flow in and out; The dust collection box has a discharge port communicating with the outside of the box, The garbage dump box is provided with a hydraulically driven loading device that is movable relative to the garbage storage box to open and close the discharge opening and moves garbage into the garbage storage box; The discharge plate is provided in the trash collection box so as to be reciprocally movable between the discharge port side and the rear side of the trash collection box, the ejection actuator is hydraulically driven and connected to the ejection plate to reciprocate the ejection plate; The hydraulic circuit includes at least a switching valve and an oil tank. The switching valve is provided in an oil passage through which hydraulic oil flows so as to connect the discharge actuator and the oil tank when the discharge plate moves to the rear side of the garbage collection box, and is configured to switch between a communication state and a cut-off state by a pilot pressure, The pilot pressure for switching the switching valve is a hydraulic pressure that is generated when the loading device is driven.

2. The loading device is driven by a plurality of loading hydraulic actuators; 2. The refuse collection vehicle according to claim 1, wherein the pilot pressure detection position is closer to the hydraulic power source than the plurality of loading hydraulic actuators.

3. The hydraulic circuit includes a relief valve, 3. The refuse collection vehicle according to claim 1, wherein the switching valve and the relief valve are connected in parallel to the oil tank.

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