JP3570682B2 - Opening / closing section liquid-tight structure, liquid-tight tank and dump truck equipped with the liquid-tight tank - Google Patents

Description

The present invention relates to a liquid-tight structure and a liquid-tight tank that can be loaded liquid-tightly on a dump truck, which is a land transportation means, even with a liquid-containing substance containing a large amount of liquid such as construction sludge , and a dump truck provided with this liquid-tight tank .

  A dump truck with a large loading capacity is used to carry earth and sand used in civil engineering and construction sites to the site and to carry out construction waste soil discharged from the site. However, the dump truck carrier is suitable for transporting solid soil with almost no water content, but transports muddy soil such as tunnel excavated soil containing a large amount of water and dredged soil discharged from marine and river dredging sites. As a result, mud spilled out of the gap in the loading platform and unintentionally soiled the road. On the other hand, although there are special vehicles other than ordinary dump trucks, such as gasoline trucks and tank trucks, that carry a specified load, they transport muddy soil containing a large amount of moisture together with gravel and soil of various sizes. Could not be used.

It seems that various improvements have been made to the liquid-tight structure of the dump truck bed.For example, in order to be able to transport liquid while being a normal dump truck, the joints of the members constituting the cargo bed are subjected to packing treatment. (Patent Literature 1), and an invention in which a sealing cover covering an upper opening and a locking mechanism therefor are provided (Patent Literature 2).
JP-A-10-16634 Japanese Utility Model Publication No. 5-32113

  By the way, if the load is a liquid such as water or oil, it is easy to return to a watertight state when the door is closed, but mud such as construction sludge and dredged soil has various sizes together with water. Not only is the earth and sand mixed, but it easily adheres to the cargo bed. For this reason, if the rear door is opened, such as when discharging mud, mud tends to adhere to the watertight packing, and once adhered, it is difficult to maintain a watertight structure, and mud flows out of the slight gap that has occurred. There was a problem of doing it.

  However, in order to easily carry out the load from the carrier, a structure in which the carrier is inclined by a hydraulic cylinder with respect to the body of the dump truck to open the lower side of the rear door is very convenient in handling. Therefore, there is a need for a means for closing the rear door easily and strongly with a small force to maintain liquid tightness while maintaining this structure.

Therefore, the present invention has been made to solve this problem, and while maintaining the structure capable of discharging the load by tilting the bed of the dump truck, it is possible to reliably carry in and carry out the mud repeatedly. It is an object to obtain a liquid-tight structure and a liquid-tight tank capable of obtaining a liquid-tight state and transporting sludge without polluting a road , and a dump truck provided with this liquid-tight tank .

  That is, in the present invention, the opening / closing part liquid-tight structure in which the opening / closing door that closes the rear end openings of the left and right side plates and the bottom plate along the front-rear direction of the dump truck is mounted so as to be able to open one side with the upper part of the rear end opening as a fulcrum. A hook piece for pressing and locking the opening / closing door is provided at the end opening, and the hook piece has a rear end attached to a rotation support shaft whose axis is in the vehicle width direction. Interlocking with the movement of the drive shaft provided in the direction perpendicular to the center of the shaft, the tip of the drive shaft rotates about the rotation support shaft, and the door is pressed and locked at the rear end opening. The opening / closing section has a liquid-tight structure.

  Since the opening / closing door is pivotally opened about the upper fulcrum, and pressed and locked by the hook pieces at the lower portion, the opening / closing door can be pressed strongly against the rear end opening as a whole. When the drive shaft is formed on the opening / closing door, the hook piece can be rotated by the up and down movement, and when the drive shaft is formed on the bottom plate, by the forward and backward movement, the simple device structure enables reliable liquid supply. Denseness is obtained. The hook piece has a rear end attached to a rotation support shaft having the vehicle width direction as the axial direction, and the drive shaft provided in a direction perpendicular to the axial direction of the rotation support shaft in the axial direction. In conjunction with, the distal end portion rotates around the rotation support shaft (in a direction perpendicular to the rotation support shaft), so that the pressing and releasing operations by the hook pieces are performed by the operation in the axial direction of the drive shaft. be able to. Therefore, the pressing force of the hook pieces can be adjusted according to the amount of movement, and a sufficient liquid-tight structure that does not leak moisture to the road can be obtained. In addition, when the drive shaft is formed on the door, the operation of the hook piece is linked to the drive shaft that moves in the vertical direction of the door. Can be moved. Therefore, the door can be opened and closed without touching the mud.

  Further, there are provided two or more hook pieces, and a connecting plate erected at an intermediate portion between a front end portion and a rear end portion of each adjacent hook piece, and a drive shaft is connected to the connecting plate, and an axis of the drive shaft is provided. In conjunction with the movement in the direction of the center, two or more hook pieces together with the connecting plate can be rotated collectively about the rotation support shaft. Therefore, the plurality of hook pieces rotate collectively by interlocking with the operation of the drive shaft in the axial direction, so that it is not necessary to provide a separate hook piece rotation mechanism, and the number of parts can be reduced. In addition, since a plurality of hook pieces rotate simultaneously, a pressing force is evenly applied to the rear end opening, and a strong liquid-tight state can be obtained. It is. Further, since a connecting plate is erected on the intermediate portion of the two or more hook pieces and the drive shaft is connected to this connecting plate, the intermediate portion of the hook piece is moved, so that the rear end portion is used as a pivot. The tip is pressed and locked. Therefore, a large rotation at the tip of the hook piece can be obtained from a slight movement of the drive shaft. Therefore, by slightly moving the drive shaft, the one-way opening door can be strongly pressed against the rear end opening, and a reliable liquid tightness of the rear end opening can be obtained.

  Regarding the liquid-tight structure of the opening / closing section, it is preferable that an auxiliary hook piece for pressing and locking the opening / closing door is provided at the rear end opening and fixed to the connecting plate in parallel with the hook piece.

  An auxiliary hook piece for pressing and locking the opening / closing door at the rear end opening is provided fixed to the connecting plate in parallel with the hook piece, so that the auxiliary hook piece works together with the hook piece to form the rear end opening and the opening / closing door. And a more reliable liquid-tight state can be obtained. In particular, since both ends of the lower part of the door are pressed and locked by the hook pieces and the intermediate part by the auxiliary hook pieces, no liquid leaks from any part of the lower part of the door.

  The drive shaft is supported by the door or the bottom plate at a position where the distance from the door or the bottom plate is shorter than the length of the hook piece protruding from the door or the bottom plate, and the tip of the hook piece is the axis of the drive shaft. The opening / closing door is operated to be larger than the operating width in the direction to press and lock the opening / closing door at the rear end opening.

  The drive shaft is supported by the door or bottom plate at a position where the distance from the door or bottom plate is shorter than the protrusion length of the hook piece protruding from the door or bottom plate, and the tip of the hook piece is in the axial direction of the drive shaft. Since the operation is larger than the operation width, a large rotation at the tip of the hook piece can be obtained from a slight movement of the drive shaft. Therefore, by slightly moving the drive shaft, the one-way opening door can be strongly pressed against the rear end opening, and a reliable liquid tightness of the rear end opening can be obtained.

  Regarding the liquid-tight structure of the opening / closing part, the rear ends of the left and right side plates are formed as inclined surfaces such that the upper end thereof is at a forward position in the front-rear direction of the dump truck and the lower end thereof is at a rearward position in this direction. It is preferable that an opening / closing door for closing the rear end opening is placed on the inclined surface.

  Since the opening / closing door for closing the rear end opening is placed on the inclined surface, a strong pressing contact with the inclined surface of the opening / closing door can be obtained by its weight. Therefore, more reliable liquid tightness of the rear end opening can be obtained.

  The above-described liquid-tight structure of the opening / closing section may be directly applied to, for example, a loading platform of a dump truck, but since it is a dedicated vehicle, the convenience of the dump truck deteriorates. Therefore, it is possible to provide a liquid-tight tank having the above-mentioned opening / closing section liquid-tight structure that can be mounted on a general dump truck.

  That is, the liquid-tight tank that achieves the above object has a left and right side plate, a front side plate, a bottom plate, and an opening / closing door that closes a rear end opening of the left and right side plate and the bottom plate. A closed tank is provided with the opening / closing section liquid-tight structure described in any of the above.

  The liquid-tight tank is provided on the left and right side plates so that tank locking projections formed on the left and right side plates of the dump truck and whose vertical edges abut against the rear can be fixed at different positions in the front and rear direction of the dump truck. It is preferable to configure as

  By adjusting the fixing position of the tank locking projection, the liquid-tight tank can be fixed without play in the front-rear direction of the dump truck, and loading stability and safety on the loading platform can be obtained.

  In addition, in the liquid-tight tank, the rear end of the bottom plate is formed as an inclined surface obliquely upward along the front-rear direction of the dump truck, and the rear end of the bottom plate is floated from the loading platform of the dump truck to rotate the hook pieces. It is preferable to provide a moving gap.

  When the drive shaft is formed on the door side, the rear end of the hook piece is fixed to the door side, and the hook piece that closes the door is rotated from below with respect to the bottom plate of the liquid-tight tank. If the rear part of the liquid-tight tank does not protrude from the rear end of the bed of the dump truck, the hook pieces interfere with the rear end of the bed and cannot rotate. However, since the rear end side of the bottom plate of the liquid-tight tank is lifted from the loading platform of the dump truck and the rotation of the hook piece is allowed by the rotation gap, the liquid-tight tank can be stored without protruding from the rear end of the loading platform. Can be structured.

According to the opening / closing unit liquid-tight structure , the opening / closing unit liquid-tight tank , and the dump truck equipped with the opening / closing unit liquid-tight tank according to the present invention, the opening / closing door that opens halfway by pressing and locking the hook piece has the rear end opening. Can be strongly pressed against. Further, the opening / closing door can be pressed strongly against the rear end opening as a whole. Therefore, reliable liquid tightness of the rear end opening can be obtained. For this reason, even if mud such as construction sludge or dredged soil, which is mixed with water and various sizes of soil and easily adheres to the cargo bed, is loaded and transported, no outflow or splashing occurs. Further, since the pressing contact with the inclined surface of the opening / closing door can be obtained by its weight, more reliable liquid tightness of the rear end opening can be obtained.

Further, according to the liquid-tight structure of the opening / closing section of the present invention, the liquid-tight tank having the liquid-tight structure of the opening / closing section, and the dump truck having the liquid-tight tank , reliable liquid-tightness can be obtained with a simple device structure. In addition, a strong pressing contact of the opening / closing door with respect to the rear end opening by pressing and locking of the hook pieces can be achieved in the entire vehicle width direction. Therefore, reliable liquid tightness of the rear end opening can be obtained. Furthermore, there is no need to provide a separate rotation mechanism for the hook pieces, and the number of components can be reduced.

  In addition, by adjusting the fixing position of the tank locking projection, the liquid-tight tank can be fixed without play in the front-rear direction of the dump truck, and loading stability and safety on the loading platform can be obtained. Further, the liquid-tight tank can be housed without protruding from the rear end of the carrier.

Hereinafter, the opening / closing unit liquid-tight structure , the liquid-tight tank provided with the opening / closing unit liquid-tight structure , and the dump truck provided with the liquid-tight tank will be described in more detail with reference to the drawings.

First Embodiment: FIG. 1 shows a state in which a liquid-tight tank 1 that can store and hold mud soil for loading and transporting the mud is inclined together with a dump truck carrier 2 to take out a load. The liquid-tight tank 1 having the liquid-tight structure of the opening and closing section of the present invention shown by the solid line in FIG. 1 is formed separately from the dump truck, and is used when the dump truck is used for purposes other than mud transportation. The liquid-tight tank 1 can be removed for use.

  The liquid-tight tank 1 mounted on the dump truck 2 is shown in FIGS. 2 is a right side view of the liquid-tight tank 1, FIG. 3 is a front view of the liquid-tight tank 1 as viewed from behind, and FIG. 4 is a plan view of the liquid-tight tank 1. The liquid-tight tank 1 follows the shape of the loading platform 2 of the dump truck, and has a hollow container shape formed by six surfaces of an upper plate 1a, a front plate 1b, left and right side plates 1c, a rear plate (opening / closing door) 1d, and a bottom plate 1e. are doing. The joining portion of the upper plate 1a, the front plate 1b, the left and right plates 1c, and the bottom plate 1e of the liquid-tight tank 1 is processed to be liquid-tight by welding or the like and fixed so that it cannot be opened and closed. In this embodiment, the upper plate 1a is provided. However, the upper plate 1a may not be formed as a member of the liquid-tight tank 1.

  On the other hand, the opening / closing door 3 forming the rear plate 1d of the liquid-tight tank 1 is closed when the mud is transported to prevent the outflow of the mud, and when discharging the mud, it is opened together with the inclination of the bed 2 to discharge the mud. Function. A packing 3e made of rubber or the like (see FIGS. 8 and 9) is fitted into a portion of the opening and closing door 3 which abuts on the liquid-tight tank 1, so that the liquid-tight tank 1 is held in a liquid-tight manner. I have. FIG. 6 shows an enlarged right side view of the rear end side of the liquid-tight tank 1. As can be seen from this figure, the rear end portions of the left and right side plates 1c are located at the front ends in the front-rear direction of the dump truck. It is formed as an inclined surface 3g such that the lower end portion is located at a rearward position in the direction at the position of the deviation. The opening / closing door 3 is placed on a rear end opening formed as an inclined surface 3g at the rear end of the left and right side plates 1c and the bottom plate 1e. On the upper part of the opening and closing door 3, a turning support shaft 3f along the vehicle width direction is provided on the upper part of the upper plate 1a above the rear end opening so that the opening and closing door 3 can be opened to one side with respect to the liquid tight tank 1. A hook-shaped upper connecting portion 3a pivotally attached to the rotation support shaft 3f projects upward from the opening and closing door 3.

  Further, a lock mechanism for holding the liquid-tight tank 1 in a liquid-tight state is attached to the door 3. When the mud is loaded, the lock mechanism presses the open / close door 3 against a rear end opening formed by the left and right side plates 1c and the bottom plate 1e along the front-rear direction of the dump truck, and closes in a liquid-tight manner. In addition, it has a function of releasing the pressure on the rear end opening of the opening / closing door 3 when the mud is carried out. As shown in FIG. 6, the lock mechanism includes an operation handle 4 as an operation member, a drive shaft 5, a hook piece 6 c, and the like, and is provided on the door 3. A series of members related from the handle 4, which is an operation member, to the operation of moving the hook piece 6c is referred to as a lock mechanism.

  The hook piece 6c has a function of rotating and pressing and locking the rear end of the bottom plate 1e so as to embrace it from below. Two hook pieces 6c are provided in the vehicle width direction, and these hook pieces 6c are attached to a rotation support shaft 8 having a rear end 6e whose axial direction is the vehicle width direction. An intermediate portion of these hook pieces 6c is bridged by a connecting plate 6a. In addition to the fact that the tip of the hook piece 6c is bent in a hook shape, the portion that engages with the hook locking projection 12 formed at the rear end of the bottom plate 1e is inclined rearward from the top as it goes downward. It is an inclined surface.

  The connecting plate 6a has a length in the vehicle width direction of the opening / closing door 3, and has a cross section having a shape obtained by rotating the character "H" by 90 degrees. In addition to the hook piece 6c, an auxiliary hook piece 6g that is locked to the bottom plate 1e is formed on the connecting plate 6a in parallel with the hook piece 6c, and a drive shaft receiving portion 6d that holds the drive shaft 5 is provided. ing. Two hook pieces 6c are formed at both ends of a connecting plate 6a along the vehicle width direction, and two auxiliary hook pieces 6g are formed at an intermediate portion thereof. The tip end of the hook piece 6c and the auxiliary hook piece 6g rotate so as to embrace the rear end of the bottom plate 1e from below and press and lock. 8 and 9 are sectional views taken along line SB-SB in FIG. 3 and show enlarged views of the rear end portion of the liquid-tight tank 1. As shown in FIGS. The portion 6 d is formed so as to rotatably connect a thrust bearing 6 b holding the drive shaft 5, and to allow the connection plate 6 a to rotate with respect to the drive shaft 5. If the connecting plate 6a is pushed down too much by the drive shaft 5, the hook piece 6c may hit the carrier 2 of the dump truck. Therefore, a pin fixing portion 6f for preventing the hook piece 6c is provided on the upper part of the connecting plate 6a ( 3 and 11).

  The hook body 6 is formed by the hook pieces 6c, the connecting plate 6a, and the auxiliary hook pieces 6g. The hook body 6 operates integrally.

  FIG. 7 is an enlarged vertical sectional view around the drive shaft 5 of the lock mechanism. One end of the drive shaft 5 is connected to the operation handle 4 to transmit the rotation of the operation handle 4. On the other hand, the other end is supported by a thrust bearing 6b. Further, it is screwed with a nut 3c fitted into a drive shaft support 3b protruding from the upper part of the door 3 to the rear of the vehicle. A stopper handle 7 for preventing the drive shaft 5 from rotating and moving up and down due to vibration or the like is formed.

  As shown in FIG. 4, the upper surface of the liquid-tight tank 1 is provided with an upper plate 1a provided with an opening (upper opening) 10 for introducing mud at the center thereof so that the mud is not easily scattered even during the operation of the dump truck. Is blocked by The upper surface opening 10 is formed wide so that the mud can be easily carried in by a device such as a backhoe. The lids 10a for closing the upper opening 10 of the upper plate 1a are each plate-shaped, placed in parallel on the upper opening 10, and fixed by an angle mechanism 10b shown in FIG. As the lid 10a, a metal plate such as an iron plate, a plywood made of wood such as veneer as a main raw material, a plastic, or the like can be used. Further, it is preferable that a margin is provided at an edge of the lid 10a so that no gap is generated when the individual lid 10a is placed on the upper surface opening 10 and the lid 10a is not easily removed.

The left and right side plates 1c of the liquid-tight tank 1 shown in FIG. 1 are fixed at two points with the tilt of the dump truck to prevent the liquid-tight tank 1 from falling off the dump truck carrier 2. At the rear end of the left and right side plates 1c, tank locking projections 11 are formed to protrude in the vehicle width direction of the dump truck to further reinforce the fixing force. It is locked so as to abut against the plate edge along the direction from the rear. Therefore, the liquid-tight tank 1 does not slip off from the carrier 2 even when the carrier 2 is inclined when the mud is carried out, by the tank locking projections 11. Since the mounting position of the tank locking projection 11 differs depending on the size of the left and right side plates of the dump truck, the tank locking projection 11 is detachably formed at different positions in the front and rear direction of the dump truck, and is positioned at a predetermined position according to the dump truck to be applied. It has been stopped, et al. with a screw 13 Te.

  Inside the left and right plates 1c, horizontal protrusions (not shown) projecting about 10 cm into the liquid-tight tank 1 are formed with an appropriate length along the vehicle front-rear direction. The projecting piece serves as a capacity meter as a measure of the amount of mud carried into the liquid-tight tank 1, and also serves as a bounce to prevent the mud from jumping up the right and left side plates 1c when the dump truck rolls. Also have.

  The bottom plate 1e of the liquid-tight tank 1 has a rear end portion formed as an inclined surface 1f obliquely upward along the front-rear direction of the dump truck, and a rear end portion of the bottom plate 1e is floated from the dump truck carrier to form a hook piece 6c. A turning gap is provided. Since the hook pieces 6c are locked by the hook locking projections 12 formed at the rear end of the bottom plate 1e of the liquid-tight tank 1, a space for the hook pieces 6c to enter below the bottom plate 1e of the liquid-tight tank 1. Is necessary. Thus, since the inclined surface 1f is provided on the bottom plate 1e, there is no need to provide the bottom plate 1e with a raised bottom on the loading platform 2, and the space of the loading platform 2 can be effectively utilized.

  Next, the operation of the opening / closing section liquid-tight structure used in this dump truck will be described.

  When carrying in mud, it is necessary to make the liquid-tight tank 1 liquid-tight. Therefore, it is necessary to close the opening / closing door 3 and lock the hook pieces 6 c with the hook locking projections 12 of the liquid-tight tank 1. is there. First, the loading platform 2 of the dump truck is leveled, and the door 3 is closed by its own weight. The tip of the hook piece 6c is out of the hook locking projection 12 formed on the bottom plate 1e of the liquid tight tank 1 (see FIG. 8). When the operation handle 4 is manually rotated counterclockwise (left rotation), the drive shaft 5 rotates counterclockwise with the rotation of the operation handle 4. As shown in FIG. 7, the drive shaft 5 is screwed with a nut 3c built in a drive shaft support 3b protruding from the door 3 to the rear of the vehicle. The drive shaft 5 rises. A thrust bearing 6b is provided at the other end of the drive shaft 5, and a connection plate 6a having a drive shaft receiving portion 6d rotatably connected to the thrust bearing 6b also rises. On the other hand, as shown in FIG. 10, the rear end portion 6e of the hook piece 6c is fixed to the hook body support portion 3d protruding from the opening / closing door 3 by the rotation support shaft 8, so that the middle of the hook piece 6c is provided. The connecting plate 6a in the portion starts to rotate upward around the rotation support shaft 8. At this time, since the tip of the hook piece 6c is located outside the connecting plate 6a around the rotation support shaft 8, the vertical displacement of the tip of the hook piece 6c is more than the vertical displacement of the drive shaft 5. growing. That is, the tip of the hook piece 6c formed in a hook shape is large upward, and rotates and moves about the rotation support shaft 8. The tip of the hook piece 6c is bent in the shape of a hook, and the portion that engages with the hook locking projection 12 has an inclined surface that is inclined rearward from the upper side to the lower side of the drive shaft 5c. As the position is raised, the tip of the hook piece 6c strongly presses and locks the hook locking projection 12 formed on the liquid-tight tank 1, and the door 3 is liquid-tightly tightened to the rear end opening (FIG. 10B). Thereafter, the mud is carried in from the upper opening 10 by a backhoe or the like, but the liquid-tight tank 1 is kept liquid-tight.

  Next, the operation when the stored and retained mud is carried out will be described.

  When the mud is carried out, the operation works opposite to the operation of closing the hook piece 6c. That is, when the operation handle 4 is rotated clockwise (to the right), the drive shaft 5 is lowered, and the hook piece 6c pushed by the drive shaft 5 is rotated downward about the rotation support shaft 8 to connect the connecting plate. The tip of the hook piece 6c pivots largely downward as compared to when the button 6a is pressed. Thereby, the hook piece 6c and the liquid-tight tank 1 are unlocked. When the tip of the hook 6c is excessively pushed down, the pin fixing portion 6f provided on the vehicle rear side of the connecting plate 6a rotates about the rotation support shaft 8 in conjunction with the connecting plate 6a, It comes into contact with the door 3. Therefore, the rotation of the connecting plate 6a stops, and the hook piece 6c does not descend any further. Next, in this state, when the loading platform 2 is tilted so as to lift the front end of the dump truck around its rear end, the liquid-tight tank 1 placed on the loading platform 2 tilts together with the loading platform 2, and The opening / closing door 3 swings around the pivot shaft 3f above the rear end opening and hangs down by its own weight to open. Then, the mud stored in the liquid-tight tank 1 is discharged (see FIG. 1).

  In the liquid-tight structure of the present invention, by operating one drive shaft 5, the hook pieces 6c and the auxiliary hook pieces 6g that can be locked to the liquid-tight tank 1 at a plurality of positions are simultaneously operated. Bad portions are unlikely to occur, and a liquid-tight state can be reliably obtained. By slightly raising and lowering the drive shaft 5, a large movement of the hook piece 6c can be obtained, and a part of the tip of the hook piece 6c or the auxiliary hook piece 6g that engages with the hook locking projection 12 is formed. Since the inclined surface is inclined from the upper part to the lower part toward the rear of the vehicle, the upward movement of the drive shaft 5 pushes the open / close door 3 toward the front of the vehicle. Strong pressing force can be obtained. Further, since the lock mechanism is formed on the door 3, the rear end of the bottom plate 1e can be made liquid-tight by making the rear end side of the inclined surface 1f, and the provision of the lock mechanism almost reduces the tank capacity. And is easy to operate manually.

Second Embodiment In the first embodiment, the drive shaft 5 is manually operated by the screw feed mechanism. However, the drive shaft 5 can be automatically operated by using a hydraulic mechanism provided in a dump truck. . The description of the same configuration as that using the screw feed mechanism is omitted.

  FIG. 12 corresponds to FIG. 9 in the first embodiment, and is an enlarged vertical sectional view around the opening / closing door showing a lock mechanism using hydraulic pressure. The hydraulic cylinder 21 transmits power to a rod 21a by moving a piston in the cylinder by hydraulic pressure. One end of the hydraulic cylinder 21 is connected to a drive shaft support 3b protruding rearward from the door 3, and the other end is fixed to the connecting plate 6a of the hook 6c. The hydraulic cylinder 21 is electrically connected to the electric system of the dump truck, and when the rod 21a of the hydraulic cylinder 21 is pushed out by operating a button in the driver's seat, the hook piece 6c is pressed down to release the lock. On the other hand, when the rod 21a is pulled back, the hook piece 6c is pushed up and pressed and locked with the liquid tight tank 1.

Third Embodiment: FIGS. 13 to 16 show a lock mechanism which is arranged on a bottom plate 1e of a liquid-tight tank 1 and has a hook piece which is turned and pressed and locked to the opening / closing door 3 from behind. 1e shows an embodiment provided in 1e. The description of the same parts as in the first embodiment will be omitted, and different parts will be referred to.

  As shown in FIG. 16, the hydraulic cylinder 31 is disposed at a substantially central portion of the bottom plate 1e such that the axial direction thereof is in the front-rear direction of the vehicle. On the other hand, as shown in FIG. 13, a rotation support shaft 32 formed along the vehicle width direction is provided at the rear end of the bottom plate 1e. The tip of the hydraulic cylinder 31 is pivotally connected to a shaft connecting piece 33 projecting perpendicularly from the rotation support shaft 32 by a support shaft 34. Further, two hook pieces 35 are fixed to both ends and a middle part of the rotation support shaft 32, respectively. The hydraulic cylinder 31 as a drive shaft is supported by the bottom plate 1e at a position L2 where the distance from the bottom plate 1e is shorter than the projection length L1 of the hook piece 35 protruding from the bottom plate 1e.

  As shown in FIG. 13, when the rod 31a of the hydraulic cylinder 31 is built in the cylinder, the engagement of the hook piece 35 with the hook locking projection 36 is released. When the rod 31a of the hydraulic cylinder 31 is pushed out by the electric operation, the shaft connecting piece 33 rotates in the vehicle rearward direction about the rotation support shaft 32 as shown in FIG. Accordingly, the rotation support shaft also rotates. Since four hook pieces 35 are fixed to the rotation support shaft 32, each hook piece 35 rotates about the rotation support shaft 32 in conjunction with the rotation of the rotation support shaft 32, and opens and closes. The hook 3 is pressed and locked against a hook locking projection 36 formed on the door 3. Since the hydraulic cylinder 31 is arranged at the position L2 shorter than the protrusion length L1 of the hook piece 35 protruding from the bottom plate 1e, the operating length of the tip of the hook piece 35 is longer than the operating length of the rod 31a. Therefore, the hook piece 35 can be strongly pressed and locked to the hook locking projection 36 only by moving the rod 31a a small amount. In order to release the locked state of the hook piece 35, if the rod 31a of the hydraulic cylinder 31 is pulled back, the locked state is released by the operation opposite to the case where the hook piece 35 is pressed and locked. As a modification of the third embodiment, the rotation support shaft 34 does not extend along the vehicle width direction, and the hook piece and the shaft connection piece are pivotably pivotally connected to each other to form a link. It is also conceivable to provide a drive shaft and electrically operate a plurality of drive shafts in a similar manner.

  When comparing the case where the hook piece 6c as in the first embodiment is provided on the opening / closing door 3 and the case where the hook piece 35 as in the third embodiment is provided in the bottom plate 1e, the hook provided in the bottom plate 1e has The tip of the piece is preferable in that the mud is difficult to adhere to when the mud is carried out, and the drive shaft (hydraulic cylinder 31) is inconspicuous in appearance.

Fourth Embodiment: In the fourth embodiment, the liquid tight tank 1 is not formed separately from the dump truck 2 but the dump truck 2 itself has a liquid-tight structure. That is, the door 3 and the lock mechanism shown in the first embodiment are formed in place of the rear tilt of the dump truck. When the liquid-tightness of the contact portions of the left and right side plates, the bottom plate, and the like of the dump truck carrier 2 cannot be maintained, the liquid-tightness can be maintained by filling with a filling material or reinforcing with a sealing material. . If there is no upper plate of the dump truck, the upper plate 1a as shown in the first embodiment may be attached to prevent the sludge from scattering during the operation of the dump truck.

  Note that the example shown in the above embodiment is merely an example of the present invention, and for example, the manual lock mechanism shown in the first embodiment can be arranged on the bottom plate 1e, or as shown in the third embodiment. Alternatively, a lock mechanism for fixing the plurality of hook pieces 35 to the rotation support shaft 34 along the vehicle width direction may be provided on the door 3 side. That is, the structures described in this specification can be combined as appropriate.

It is a right view which shows the state where the dump truck which loaded the liquid-tight tank which has the opening / closing part liquid-tight structure used for the dump truck of this invention inclines the loading platform. It is a right view of the liquid tight tank of FIG. It is the front view seen from the back of the liquid tight tank of FIG. It is a top view of the liquid tight tank of FIG. FIG. 5 is a schematic sectional view of an angle mechanism for fixing a lid provided on a liquid-tight tank upper plate, and is a sectional view taken along line SC-SC in FIG. 4. FIG. 2 is an enlarged right side view of a rear end portion of the liquid tight tank in FIG. 1. FIG. 3 is an enlarged view of a lock mechanism attached to the liquid-tight tank of FIG. 1, and is a cross-sectional view taken along line SA-SA of FIG. 2. FIG. 4 is an enlarged view of a rear end portion of the liquid tight tank in FIG. 1 and is a cross-sectional view taken along line SB-SB in FIG. 3. FIG. 10 is a sectional view taken along line SB-SB in FIG. 3, showing a state in which the hook pieces of FIG. 8 are locked by hook locking protrusions. FIG. 2 is an enlarged right side view around a hook piece of FIG. 1. FIG. 4 is an enlarged view of a marginal end portion of the liquid-tight tank in FIG. 1, and is a cross-sectional view taken along line SD-SD in FIG. 3. It is a longitudinal section showing the opening and closing part liquid-tight structure used for the dump truck by a 2nd embodiment of the present invention. FIG. 8 is a right side view of a liquid-tight tank according to another embodiment of the present invention, showing a state in which hook pieces are unlocked. FIG. 14 is a right side view of the liquid tight tank in FIG. 13, showing a state in which hook pieces are locked to the door. It is the front view seen from the back of the liquid tight tank of FIG. FIG. 15 is a plan view seen from below the liquid tight tank of FIG. 14.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Liquid-tight tank 1a Upper plate 1b Front plate 1c Left right plate 1d Rear plate 1e Bottom plate 1f Inclined surface 2 Loading platform 3 Door 3a Upper connection part 3b Drive shaft support part 3c Nut
3d Hook body support part 3e Packing 3f Rotating support shaft 3g Inclined surface 4 Operating handle 5 Drive shaft 6 Hook body 6a Connecting plate 6b Thrust bearing 6c Hook piece 6d Drive shaft receiving part 6e Rear end part 6f Pin fastening part 6g Auxiliary hook piece 7 Stopper handle 8 Rotating support shaft 10 Upper surface opening 10a Lid 10b Angle mechanism 11 Tank locking projection 12 Hook locking projection
13 screws 21 Hydraulic cylinder 21a Rod 31 Hydraulic cylinder 31a Rod 32 Rotation support shaft 33 Shaft connection piece 34 Support shaft 35 Hook piece 36 Hook locking projection

Claims (8)

In the liquid-tight structure of the opening / closing part in which the opening / closing door that closes the rear end opening of the left and right side plates and the bottom plate along the front and rear direction of the dump truck is attached so that the upper part of the rear end opening can be opened one-sidedly,
Two or more hook pieces for pressing and locking the opening / closing door at the rear end opening, and a connecting plate provided at an intermediate portion between the front end and the rear end of each adjacent hook piece,
The hook piece has a rear end attached to a rotating support shaft whose axial direction is the vehicle width direction, and the connecting plate is connected to a drive shaft provided orthogonal to the axial direction of the rotating support shaft. In accordance with the movement of the drive shaft in the axial direction, the front ends of the two or more hook pieces together with the connecting plate are rotated collectively about the rotation support shaft to open the opening / closing door at the rear end opening. A liquid-tight structure for the opening and closing part, wherein the liquid-tight structure is adapted to be pressed and locked to the opening.   An auxiliary hook piece for pressing and locking the opening / closing door at the rear end opening is provided fixed to the connecting plate in parallel with the hook piece, and at least the lower side of the rear end opening is pressed and locked at three or more places. The liquid-tight structure according to claim 1.   One end of the drive shaft is screwed with a drive shaft supporting portion provided on the opening / closing door or the bottom plate, and the other end is rotatably connected to the connecting plate around the axis of the drive shaft. 2. The liquid-tight structure according to claim 1, wherein the drive shaft is displaced in the axial direction by the rotation about the axis, and the tip portions of the two or more hook pieces can be rotated together with the connecting plate.   4. The liquid-tight structure according to claim 3, wherein an operation handle for rotating the drive shaft around its axis is provided on the drive shaft.   The opening / closing section liquid-tight structure according to any one of claims 1 to 4, wherein the pivot shaft having the hook pieces, the connecting plate, and the drive shaft are attached to the opening / closing door. Opening and closing the rear end of the left and right plates as an inclined surface so that the upper end is at the front position in the front-rear direction of the dump truck and the lower end is at the rear position in this direction, and the rear end opening is closed. The liquid-tight structure according to any one of claims 1 to 5 , wherein a door is placed on the inclined surface. In a liquid-tight tank that has an opening and closing door that closes the rear end opening of the left and right side plate, front side plate, bottom plate, left and right side plate and bottom plate, and can be detachably mounted on the dump truck carrier,
A liquid-tight tank, comprising the opening / closing section liquid-tight structure according to any one of claims 1 to 6 . A dump truck having the liquid-tight tank according to claim 7 removably mounted on a carrier.

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