CN219769868U - Rotary positioning device for concave bottom frame of piggyback vehicle and piggyback transport vehicle - Google Patents

Abstract

The utility model discloses a rotary positioning device of a concave chassis of a piggyback truck and the piggyback truck, the rotary positioning device comprises a base, a lifting platform, two groups of longitudinally arranged cross lifting rods and a hydraulic cylinder, wherein the two groups of longitudinally arranged cross lifting rods are arranged between the base and the lifting platform, a positioning shaft assembly is arranged on the top surface of the lifting platform, one end of the hydraulic cylinder is hinged with the base, and the other end of the hydraulic cylinder is hinged with the lifting platform. The rotary positioning device not only shortens the structural size, but also can enhance the capability of the structure to resist transverse force.

Description

Rotary positioning device for concave bottom frame of piggyback vehicle and piggyback transport vehicle

Technical Field

The utility model relates to the technical field of railway vehicles, in particular to a rotary positioning device for a concave bottom frame of a piggyback vehicle. The utility model also relates to a piggyback transport vehicle provided with the rotary positioning device.

Background

The railway piggyback transportation is a convenient highway-railway intermodal transportation mode that after the whole highway truck or the semitrailer loads cargoes, the cargoes are loaded to a railway special vehicle at an origin railway station, and after the long-distance transportation is completed through a railway and the cargoes reach a destination railway station, the highway truck drives away from the railway special vehicle and drives to a final destination.

The transportation mode is convenient for transporting goods, the damage of the goods in the transportation process can be reduced without intermediate transportation and flip-chip, and the transportation mode has unique flexibility and can be used for loading and unloading the goods at the place and time selected by a cargo owner.

The piggyback transportation can fully exert the advantages of convenience 'door-to-door' service of the highway, long distance, all weather, safety, punctual, energy conservation and environmental protection, large batch and low cost of the railway transportation, can effectively twist the current situation of single multi-type intermodal line and primary service in China, and can provide brand-new logistics and service experience for users. Therefore, based on the piggyback transportation mode of door-to-door and just-in-time, the method can win the acceptance of users and wide market space under the background of increasingly pursuing low freight rate, rapidness, safety and just-in-time of the freight transportation, and has better development prospect.

The piggyback transport vehicle generally realizes the function of rotation lifting through a rotation positioning device in the middle of a concave bottom frame, so that a highway truck can automatically go up and down a railway vehicle to realize loading and unloading.

As shown in fig. 1 and 2, in the related art, the rotary positioning device is composed of a base 1, a hydraulic cylinder 4, a lifting table 2 and two groups of crossed lifting rods 3 which are crossed in an X shape, the hydraulic cylinder 4 is positioned at one side of the lifting table 2, a push rod of the hydraulic cylinder 4 is connected with the crossed lifting rods 3 through a connecting rod, and when the hydraulic cylinder 4 stretches, the lifting table 2 can be driven to lift or descend through the crossed lifting rods 3.

The rotary positioning device in the structural form has the defects of larger structural size, weaker transverse force resistance capability of the lifted structure and the like.

Disclosure of Invention

The utility model aims to provide a rotary positioning device for a concave bottom frame of a piggyback vehicle. The rotary positioning device not only shortens the structural size, but also can enhance the capability of the structure to resist transverse force.

Another object of the present utility model is to provide a piggyback transport provided with the rotary positioning device for a concave chassis of a piggyback.

In order to achieve the above purpose, the utility model provides a rotary positioning device for a concave chassis of a piggyback vehicle, comprising a base, a lifting platform, two groups of longitudinally arranged crossed lifting rods and a hydraulic cylinder, wherein the two groups of longitudinally arranged crossed lifting rods are positioned between the base and the lifting platform, the top surface of the lifting platform is provided with a positioning shaft assembly, one end of the hydraulic cylinder is hinged with the base, and the other end of the hydraulic cylinder is hinged with the lifting platform.

Optionally, in the vertical direction, a hinge point at which the hydraulic cylinder is hinged to the base is located below the positioning shaft assembly.

Optionally, the base is provided with an oil cylinder support, the lower surface of the lifting platform is provided with a push rod support, one end of the hydraulic cylinder is hinged with the oil cylinder support, and the other end of the hydraulic cylinder is hinged with the push rod support.

Optionally, the base is provided with a lower longitudinal hinging seat and a lower longitudinal sliding seat, and the lifting platform is provided with an upper longitudinal hinging seat and an upper longitudinal sliding seat; the hinged ends of the two groups of longitudinally arranged cross lifting rods are hinged with the lower longitudinal hinging seat and the upper longitudinal hinging seat through pin shafts, and the sliding ends of the two groups of longitudinally arranged cross lifting rods are in sliding fit with the longitudinal sliding ways of the lower longitudinal sliding seat and the upper longitudinal sliding seat through pin shafts.

Optionally, the device further comprises two groups of cross lifting rods which are arranged transversely, and the two groups of cross lifting rods which are arranged transversely are respectively positioned at the front side and the rear side of the two groups of cross lifting rods which are arranged longitudinally.

Optionally, the base is provided with a lower transverse hinging seat and a lower transverse sliding seat, and the lifting platform is provided with an upper transverse hinging seat and an upper transverse sliding seat; the hinged ends of the two groups of transversely arranged cross lifting rods are hinged with the lower transverse hinging seat and the upper transverse hinging seat through pin shafts, and the sliding ends of the two groups of transversely arranged cross lifting rods are in sliding fit with the transverse sliding ways of the lower transverse sliding seat and the upper transverse sliding seat through pin shafts.

Optionally, the sliding end of the cross lifting rod is provided with a lower roller and an upper roller, the lower roller is contacted with the upper surface of the base, and the upper roller is contacted with the lower surface of the lifting table.

Optionally, one of the lower roller and the upper roller is a single roller mounted in the middle or on one side of the sliding end of the cross lift bar.

Optionally, a roller mounting groove is formed in the middle of the sliding end of the cross lifting rod in the thickness direction.

Optionally, one of the lower roller and the upper roller is a double roller, which is mounted on both sides of the sliding end of the cross lifting rod.

Optionally, the first lifting rod and the second lifting rod of the crossed lifting rod are hinged through a pin shaft, a clamping groove is formed in the end portion of the pin shaft, a counter bore for accommodating the head portion of the pin shaft is formed in the first lifting rod, a clamping plate clamped with the clamping groove of the pin shaft is arranged on the second lifting rod, and the clamping plate is fixed to the second lifting rod through a screw.

Optionally, the positioning shaft assembly includes a positioning shaft and a shaft sleeve, the positioning shaft is welded with a top plate of the lifting table, the shaft sleeve is limited on the positioning shaft by a bolt and a washer, and the shaft sleeve can rotate around the positioning shaft.

In order to achieve the other purpose, the utility model also provides a piggyback transport vehicle, which comprises a concave underframe and a rotary positioning device arranged on the concave underframe, wherein the rotary positioning device is any one of the concave underframe rotary positioning devices of the piggyback transport vehicle.

According to the concave bottom frame rotary positioning device of the piggyback vehicle, lifting action is realized through driving of the hydraulic cylinder, when the push rod of the hydraulic cylinder is pushed to the maximum stroke position, the push rod of the hydraulic cylinder is lifted to the highest position state, and when the push rod of the hydraulic cylinder is contracted to the minimum stroke position, the push rod of the hydraulic cylinder is lowered to the lowest position state. Because the articulated joint of pneumatic cylinder and base looks articulated is located the inside region between two sets of vertical cross lifting rod that set up, in flexible in-process, the pneumatic cylinder is located the below of lifting platform all the time, does not occupy the space of lifting platform peripheral region, consequently, can obviously shorten the structure size, moreover, through setting up the pneumatic cylinder in the cross lifting rod inside, can also show the reinforcing structure and resist the ability of transverse force to improve rotation positioner's stability and reliability in use.

The piggyback transport vehicle provided by the utility model is provided with the rotary positioning device of the concave bottom frame of the piggyback vehicle, and the rotary positioning device of the concave bottom frame of the piggyback vehicle has the technical effects.

Drawings

FIG. 1 is a schematic view of a typical rotary positioning device falling to a lowermost position;

FIG. 2 is a schematic view of the rotary positioning device shown in FIG. 1 when the rotary positioning device is lifted to a highest position;

fig. 3 is a schematic structural view of a concave chassis rotating and positioning device for a piggyback according to a first embodiment of the present utility model;

FIG. 4 is an exploded view of the piggyback concave chassis rotational positioning device of FIG. 3;

FIG. 5 is a schematic view of the structure of the lift table shown in FIG. 4;

FIG. 6 is a schematic view of the base shown in FIG. 4;

FIG. 7 is a schematic view of the first lift truck of the cross lift truck shown in FIG. 4;

FIG. 8 is a schematic view of a second lift bar of the cross lift bar shown in FIG. 4;

FIG. 9 is a schematic view of the longitudinally disposed cross-lift bar of FIG. 4;

FIG. 10 is a schematic view of the longitudinally disposed cross-lift bar of FIG. 4 from another perspective;

FIG. 11 is a schematic view of the concave chassis rotational positioning device of the piggyback of FIG. 3 raised to a highest position;

FIG. 12 is a schematic view of the concave chassis rotational positioning device of the piggyback of FIG. 3 in a lowered position;

FIG. 13 is a schematic view of a second embodiment of a rotary positioning device for a concave chassis of a piggyback;

FIG. 14 is an exploded view of the piggyback concave chassis rotational positioning device of FIG. 13;

FIG. 15 is a schematic view of the structure of the lift table shown in FIG. 14;

FIG. 16 is a schematic view of the structure of the base shown in FIG. 14;

FIG. 17 is a schematic view of the first lift bar of the longitudinally disposed cross lift bar of FIG. 14;

FIG. 18 is a schematic view of a second lift bar of the longitudinally disposed cross lift bar of FIG. 14;

FIG. 19 is a schematic view of the cross lift bar shown in FIG. 14;

FIG. 20 is a schematic view of the cross-lift bar of FIG. 14 from another perspective;

FIG. 21 is a schematic view of the concave bottom frame rotational positioning device of the piggyback of FIG. 13 raised to a highest position;

figure 22 is a schematic view of the concave chassis rotational positioning device of the piggyback of figure 13 in a lowered position.

In the figure:

1. base 11, cylinder mount 12, lower longitudinal hinge mount 13, lower longitudinal slide mount 131, longitudinal slide 14, lower lateral hinge mount 15, lower lateral slide mount 151, lateral slide 2, lifting table 21, push rod mount 22, upper longitudinal hinge mount 23, upper longitudinal slide mount 231, longitudinal slide 24, upper lateral hinge mount 25, upper lateral slide mount 251, lateral slide 3, cross lift bar, first lift bar 32, second lift bar 33, lower roller 34, upper roller 35, sleeve 4, hydraulic cylinder 5, locating shaft assembly 51, locating shaft 52, sleeve 6, cardboard

Detailed Description

In order to better understand the aspects of the present utility model, the present utility model will be described in further detail with reference to the accompanying drawings and detailed description.

In the present specification, the terms "upper, lower, inner, outer" and the like are established based on the positional relationship shown in the drawings, and the corresponding positional relationship may be changed according to the drawings, so that the terms are not to be construed as absolute limitation of the protection scope; moreover, relational terms such as "first" and "second", and the like, may be used solely to distinguish one element from another element having the same name, without necessarily requiring or implying any actual such relationship or order between such elements.

Referring to fig. 3 and 4, fig. 3 is a schematic structural diagram of a concave chassis rotating and positioning device for a piggyback according to a first embodiment of the present utility model; fig. 4 is an exploded view of the concave chassis rotational positioning device of the piggyback shown in fig. 3.

As shown in the figure, in a specific embodiment, the concave bottom frame rotary positioning device of the piggyback car mainly comprises a base 1, a lifting table 2, two groups of longitudinally arranged crossed lifting rods 3, a hydraulic cylinder 4 and other components.

Two sets of longitudinally arranged crossed lifting rods 3 are positioned between the base 1 and the lifting table 2, the top surface of the lifting table 2 is provided with a positioning shaft assembly 5, the positioning shaft assembly is provided with a positioning shaft 51 and a shaft sleeve 52, the positioning shaft 51 is welded with the top plate of the lifting table 2, the shaft sleeve 52 is limited on the positioning shaft 51 through bolts and washers, and the shaft sleeve 52 can rotate around the positioning shaft 51 so as to realize a rotating function.

One end of the hydraulic cylinder 4 is hinged with the base 1, the other end of the hydraulic cylinder 4 is hinged with the lifting table 2, a hinged point of the hydraulic cylinder 4 hinged with the base 1 is located in an inner area between two groups of longitudinally arranged crossed lifting rods 3, and a hinged point of the hydraulic cylinder 4 hinged with the base 1 is located under the positioning shaft assembly 5 in the vertical direction.

Referring to fig. 5 to 10, fig. 5 is a schematic structural diagram of the lifting platform shown in fig. 4; FIG. 6 is a schematic view of the base shown in FIG. 4; FIG. 7 is a schematic view of the first lift truck of the cross lift truck shown in FIG. 4; FIG. 8 is a schematic view of a second lift bar of the cross lift bar shown in FIG. 4;

FIG. 9 is a schematic view of the longitudinally disposed cross-lift bar of FIG. 4; fig. 10 is a schematic view of the longitudinally disposed cross-lift bar of fig. 4 from another perspective.

As shown in the figure, the base 1 is provided with an oil cylinder support 11 in the middle, the lower surface of the lifting table 2 is provided with a push rod support 21, one end of the hydraulic cylinder 4 is hinged with the oil cylinder support 11, and the other end of the hydraulic cylinder 4 is hinged with the push rod support 21.

The base 1 is provided with a lower longitudinal hinging seat 12 and a lower longitudinal sliding seat 13 which are symmetrically arranged left and right, the lower longitudinal hinging seat 12 and the lower longitudinal sliding seat 13 on each side are of an integrated structure, the lifting table 2 is provided with an upper longitudinal hinging seat 22 and an upper longitudinal sliding seat 23, and the upper longitudinal hinging seat 22 and the upper longitudinal sliding seat 23 on each side are of a split structure.

The hinge ends of the two sets of longitudinally arranged cross lifting rods 3 are hinged with the lower longitudinal hinge seat 12 and the upper longitudinal hinge seat 22 through pin shafts, the sliding ends of the two sets of longitudinally arranged cross lifting rods 3 are in sliding fit with the longitudinal slide rails 131 of the lower longitudinal sliding seat 13 and the longitudinal slide rails 231 of the upper longitudinal sliding seat 23 through pin shafts, and the longitudinal slide rails 131 and 231 are designed into the shape of long round holes.

Each group of the cross lifting rods 3 is formed by hinging a first lifting rod 31 and a second lifting rod 32 through a pin shaft, the first lifting rod 31 and the second lifting rod 32 are in a shape which gradually widens from two ends to the middle so as to increase structural strength, and the first lifting rod 31 and the second lifting rod 32 are respectively provided with three pin holes so as to form a lifting rod cross assembly after being installed through the pin shaft, the cotter pin and the like, and further form a lifting steel structure with a lifting table and a base.

The pin shaft which is used for hinging the first lifting rod 31 with the second lifting rod 32 is provided with a clamping groove at the end part, the first lifting rod 31 is provided with a counter bore for accommodating the T-shaped head part of the pin shaft, the second lifting rod 32 is provided with a clamping plate 6 which is clamped with the clamping groove of the pin shaft, and the clamping plate 6 is fixed on the side surface of the second lifting rod 32 through a screw.

In order to prevent the pin shafts of the first lifting rod 31 and the second lifting rod 32 from generating strong friction with the upper and lower longitudinal slide ways 231 and to improve the service life of the mechanism, a lower roller 33 and an upper roller 34 are arranged at the sliding end of the crossed lifting rod 3, the lower roller 33 is contacted with the upper surface of the base 1, and the upper roller 34 is contacted with the lower surface of the lifting table 2.

In this embodiment, the upper roller 33 is a single roller, which is mounted on the inner side of the sliding end of the cross lifting rod 3, and the lower roller 34 is a double roller, which is mounted on two sides of the sliding end of the cross lifting rod 3, so as to bear larger force.

With continued reference to fig. 11 and 12, fig. 11 is a schematic structural view of the concave chassis rotational positioning device of the piggyback of fig. 3 when it is raised to the highest position; fig. 12 is a schematic view of the concave chassis rotational positioning device of the piggyback of fig. 3 in a lowered position.

During operation, lifting is achieved through driving of the hydraulic cylinder 4, the lifting table 2 is driven to ascend when the push rod of the hydraulic cylinder 4 extends out, and the lifting table 2 is driven to descend when the push rod of the hydraulic cylinder 4 retracts.

When the hydraulic push rod is pushed to the maximum stroke position, the hydraulic push rod is lifted to the highest position state, at the moment, the hydraulic cylinder 4 has a larger elevation angle, about 60-70 degrees, and when the hydraulic push rod is contracted to the minimum stroke position, the hydraulic push rod is lowered to the lowest position state, and the hydraulic cylinder 4 has a smaller elevation angle and is close to the horizontal state.

Since two sets of intersecting lifting rods 3 are provided in total, for each set of intersecting lifting rods 3, the upper end of the first lifting rod 31 provided with the upper roller 34 is slidably connected with the longitudinal slide rail 231 of the upper longitudinal sliding seat 23 through a pin shaft, and the lower end of the second lifting rod 32 provided with the lower roller 33 is slidably connected with the longitudinal slide rail 131 of the lower longitudinal sliding seat 13 through a pin shaft.

When the device is in the highest position, the push rod of the hydraulic cylinder 4 is extended to the longest position, and the roller pins of the first lifting rod 31 and the second lifting rod 32 are in the leftmost positions of the longitudinal slides 131, 231. When the device is in the bottommost position, the push rod of the hydraulic cylinder 4 is extended to the shortest position, and the roller pins of the first lifting rod 31 and the second lifting rod 32 are in the rightmost positions of the longitudinal slides 131, 231.

Referring to fig. 13 and 14, fig. 13 is a schematic structural view of a concave chassis rotating and positioning device for a piggyback according to a second embodiment of the present utility model; fig. 14 is an exploded view of the piggyback concave chassis rotational positioning device of fig. 13.

As shown in the figure, the present embodiment is different from the first embodiment in that, on the basis of having two sets of longitudinally disposed cross lift bars 3, there are also two sets of transversely disposed cross lift bars 3, the two sets of transversely disposed cross lift bars 3 being located on the front and rear sides of the two sets of longitudinally disposed cross lift bars 3, respectively.

In this embodiment, the same parts as those in the first embodiment are given the same reference numerals, and the same description is omitted.

Referring to fig. 15 to 20 together, fig. 15 is a schematic structural view of the lifting platform shown in fig. 14; FIG. 16 is a schematic view of the structure of the base shown in FIG. 14; FIG. 17 is a schematic view of the first lift bar of the longitudinally disposed cross lift bar of FIG. 14; FIG. 18 is a schematic view of a second lift bar of the longitudinally disposed cross lift bar of FIG. 14; FIG. 19 is a schematic view of the cross lift bar shown in FIG. 14; fig. 20 is a schematic view of the cross-lift bar of fig. 14 from another perspective.

Specifically, in order to mount two sets of cross lifting rods 3 arranged transversely, the base 1 is provided with two sets of lower transverse hinging seats 14 and lower transverse sliding seats 15, and the lifting table 2 is provided with two sets of upper transverse hinging seats 24 and upper transverse sliding seats 25; the hinged ends of the two groups of cross lifting rods 3 which are transversely arranged are hinged with the lower transverse hinging seat 14 and the upper transverse hinging seat 24 through pin shafts, the sliding ends of the two groups of cross lifting rods 3 which are transversely arranged are in sliding fit with the transverse slideway 151 of the lower transverse sliding seat 15 and the transverse slideway 251 of the upper transverse sliding seat 25 through pin shafts, and the specific connection mode is that the cross lifting rods 3 which are longitudinally arranged are referred to.

It should be noted that, in the second embodiment, the mounting manner of the rollers is changed, the middle position of the sliding end of the cross lifting rod 3 in the thickness direction is provided with a roller mounting groove, the upper roller 33 and the lower roller 34 are mounted in the roller mounting groove through pins, and meanwhile, the sleeve 35 is welded on the outer side of the sliding end of the cross lifting rod 3 at the sliding end of the second lifting rod 32, so as to play a role in isolation, and avoid abrasion caused by direct contact between the sliding end of the second lifting rod 32 and the road slide.

With continued reference to fig. 21 and 22, fig. 21 is a schematic structural view of the concave chassis rotational positioning device of the piggyback of fig. 13 when it is raised to the highest position; figure 22 is a schematic view of the concave chassis rotational positioning device of the piggyback of figure 13 in a lowered position.

During operation, lifting is achieved through driving of the hydraulic cylinder 4, the lifting table 2 is driven to ascend when the push rod of the hydraulic cylinder 4 extends out, and the lifting table 2 is driven to descend when the push rod of the hydraulic cylinder 4 retracts.

When the hydraulic push rod is pushed to the maximum stroke position, the hydraulic push rod is lifted to the highest position state, at the moment, the hydraulic cylinder 4 has a larger elevation angle, about 60-70 degrees, and when the hydraulic push rod is contracted to the minimum stroke position, the hydraulic push rod is lowered to the lowest position state, and the hydraulic cylinder 4 has a smaller elevation angle and is close to the horizontal state.

Since four sets of intersecting lifting rods 3 are provided in total, for two sets of intersecting lifting rods 3 which are longitudinally arranged, the upper end of the first lifting rod 31 provided with the roller is slidingly connected with the longitudinal slideway 231 of the upper longitudinal sliding seat 23 through a pin shaft, and the lower end of the second lifting rod 32 provided with the roller is slidingly connected with the longitudinal slideway 131 of the lower longitudinal sliding seat 13 through a pin shaft. For the two sets of cross lifting rods 3 which are transversely arranged, the upper end of the first lifting rod 31 provided with the roller is in sliding connection with the transverse slideway 251 of the upper transverse sliding seat 25 through a pin shaft, and the lower end of the second lifting rod 32 provided with the roller is in sliding connection with the transverse slideway 151 of the lower transverse sliding seat 15 through a pin shaft.

When the device is in the highest position, the push rods of the hydraulic cylinders 4 extend to the longest position, and the roller pins of the two sets of longitudinally arranged crossed lifting rods 3, the first lifting rod 31 and the second lifting rod 32 of which are positioned at the leftmost positions of the longitudinal slideways 131 and 231. When the device is in the bottommost position and the push rod of the hydraulic cylinder 4 extends to the shortest position, the roller pins of the first lifting rod 31 and the second lifting rod 32 are positioned at the rightmost positions of the oblong holes of the longitudinal slideways 131 and 231

Similarly, when viewing two sets of laterally disposed cross lift bars 3 with the view angle changed, the roller pins of the first lift bar 31 and the second lift bar 32 will also be at the leftmost or rightmost positions of the lateral slides 151, 251.

The above embodiments are merely preferred embodiments of the present utility model, and are not limited thereto, and on the basis of these, specific adjustments may be made according to actual needs, thereby obtaining different embodiments. For example, the first lifting rod 31 and the second lifting rod 32 are designed into other shapes, or roller pins of the first lifting rod 31 and the second lifting rod 32 are in sliding fit with the lifting table 2 and the base 1 through linear guide rails, or the like. This is not illustrated here, as there are many possible implementations.

In addition to the above-mentioned concave chassis rotating positioning device for the piggyback, the present utility model also provides a piggyback transport vehicle having a concave chassis and a rotating positioning device disposed on the concave chassis, wherein the rotating positioning device is the above-mentioned concave chassis rotating positioning device for the piggyback transport vehicle, and the rest of the structure of the piggyback transport vehicle is referred to the prior art and will not be described herein.

The rotary positioning device for the concave bottom frame of the piggyback vehicle and the piggyback transport vehicle provided by the utility model are described in detail. The principles and embodiments of the present utility model have been described herein with reference to specific examples, the description of which is intended only to facilitate an understanding of the core concepts of the utility model. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the utility model can be made without departing from the principles of the utility model and these modifications and adaptations are intended to be within the scope of the utility model as defined in the following claims.

Claims (13)

1. The utility model provides a concave underframe rotation positioning device of car of carrying back, includes base, lifting platform, two sets of vertical cross lift pole and the pneumatic cylinder that set up, two sets of vertical cross lift pole are located between base and the lifting platform, the top surface of lifting platform is equipped with the location axle subassembly, the one end of pneumatic cylinder with the base articulates mutually, the other end of pneumatic cylinder with the lifting platform articulates mutually, its characterized in that, the pneumatic cylinder is located with the articulated pin joint of base looks two sets of vertical inside region between the cross lift pole.

2. The piggyback concave chassis rotational positioning device according to claim 1, wherein in a vertical direction, a hinge point at which the hydraulic cylinder is hinged to the base is located below the positioning shaft assembly.

3. The concave chassis rotating and positioning device of piggyback according to claim 2, wherein the base is provided with an oil cylinder support, the lower surface of the lifting table is provided with a push rod support, one end of the hydraulic cylinder is hinged with the oil cylinder support, and the other end of the hydraulic cylinder is hinged with the push rod support.

4. The concave chassis rotating and positioning device of piggyback according to claim 3, wherein the base is provided with a lower longitudinal hinge seat and a lower longitudinal slide seat, and the lifting table is provided with an upper longitudinal hinge seat and an upper longitudinal slide seat; the hinged ends of the two groups of longitudinally arranged cross lifting rods are hinged with the lower longitudinal hinging seat and the upper longitudinal hinging seat through pin shafts, and the sliding ends of the two groups of longitudinally arranged cross lifting rods are in sliding fit with the longitudinal sliding ways of the lower longitudinal sliding seat and the upper longitudinal sliding seat through pin shafts.

5. The piggyback concave chassis rotational positioning device according to claim 4, further comprising two sets of laterally disposed cross lifting bars, said cross lifting bars of two sets being located on the front and rear sides of said cross lifting bars of two sets being disposed longitudinally, respectively.

6. The concave chassis rotating and positioning device of piggyback according to claim 5, wherein the base is provided with a lower transverse hinge seat and a lower transverse sliding seat, and the lifting table is provided with an upper transverse hinge seat and an upper transverse sliding seat; the hinged ends of the two groups of transversely arranged cross lifting rods are hinged with the lower transverse hinging seat and the upper transverse hinging seat through pin shafts, and the sliding ends of the two groups of transversely arranged cross lifting rods are in sliding fit with the transverse sliding ways of the lower transverse sliding seat and the upper transverse sliding seat through pin shafts.

7. The concave bottom frame rotary positioning device of piggyback according to any one of claims 1 to 6, wherein a sliding end of the cross lifting rod is provided with a lower roller and an upper roller, the lower roller is in contact with an upper surface of the base, and the upper roller is in contact with a lower surface of the lifting table.

8. The piggyback car concave chassis rotational positioning device of claim 7, wherein one of the lower and upper rollers is a single roller mounted in the middle or on one side of the cross lift bar sliding end.

9. The concave chassis rotating and positioning device of piggyback according to claim 8, wherein the sliding end of the cross lifting rod is provided with a roller mounting groove at a middle position in the thickness direction.

10. The piggyback car concave chassis rotational positioning device of claim 7, wherein one of the lower and upper rollers is a double roller mounted on both sides of the cross lift bar sliding end.

11. The piggyback concave chassis rotation positioning device according to any one of claims 1 to 6, wherein a first lifting rod and a second lifting rod of the cross lifting rod are hinged through a pin shaft, a clamping groove is formed in the end portion of the pin shaft, the first lifting rod is provided with a counter bore for accommodating the head portion of the pin shaft, a clamping plate clamped with the clamping groove of the pin shaft is arranged on the second lifting rod, and the clamping plate is fixed to the second lifting rod through a screw.

12. The piggyback concave chassis rotational positioning device according to any one of claims 1 to 6 wherein said positioning shaft assembly comprises a positioning shaft and a sleeve, said positioning shaft being welded to the top plate of the lift table, said sleeve being constrained to the positioning shaft by bolts and washers, and said sleeve being rotatable about the positioning shaft.

13. A piggyback vehicle comprising a concave chassis and a rotational positioning device provided to the concave chassis, wherein the rotational positioning device is a piggyback concave chassis rotational positioning device according to any one of claims 1 to 12.