CN220977558U - Overhead U-shaped beam working vehicle - Google Patents

Abstract

The application discloses an overhead U-shaped beam working truck which comprises a frame, a traveling mechanism, a hanging bracket mechanism and a limiting mechanism, wherein the traveling mechanism is arranged on the frame to drive the frame to move; the number of the limiting mechanisms is at least two, the two ends of the frame are respectively provided with the limiting mechanisms, and the two limiting mechanisms are respectively abutted with the inner side wall of the U-shaped beam and move along the inner side wall. The working vehicle for the overhead U-shaped beam can realize mechanized construction of all types of ballast beds of the overhead U-shaped beam, and can improve the site construction progress and efficiency, including pouring construction of general ballast beds, installation and maintenance of precast slab ballast beds and the like; and through the setting of stop gear, can make the operation car keep walking along U type roof beam top.

Description

Overhead U-shaped beam working vehicle

Technical Field

The application relates to the technical field of rail transit construction, in particular to an overhead U-shaped beam working vehicle.

Background

At present, in the urban rail transit construction process, ballast bed construction on viaducts comprises general integral ballast bed and precast slab ballast bed construction, wherein most of materials are completely dumped by means of manual work and simple tools, time and labor are wasted, and the site construction progress is seriously influenced. The construction method of the elevated line U-shaped beam precast slab ballast bed adopts a construction method of firstly paving and finely adjusting and then installing a track, and conventional equipment cannot be used due to condition limitation. The construction of the common ballast bed usually adopts manpower to transport construction materials, and the construction of scattered paving has low efficiency.

The conventional materials of the foundation construction, precast slab installation and general ballast bed construction of the overhead U-shaped beam are mainly hung from the lower part of the bridge through an automobile crane to be lifted on the bridge, the ballast bed construction is completed by manual work and simple tools to transfer and spread track laying materials, later manual work is paved, more manual work is needed, and the efficiency is low. The prefabricated slab ballast bed can be laid by adopting the automobile crane under the limited condition, but if the automobile crane under the bridge cannot be used, the construction progress of laying is affected.

Disclosure of utility model

The utility model provides an overhead U-shaped beam working truck, which aims to solve the technical problems of low construction efficiency and slow progress in the prior art.

In order to achieve the above purpose, the technical scheme provided by the utility model is as follows:

The utility model provides an overhead U-shaped beam working truck, which comprises a truck frame, a traveling mechanism, a hanging frame mechanism and a limiting mechanism, wherein the traveling mechanism is arranged on the truck frame to drive the truck frame to move; the number of the limiting mechanisms is at least two, the limiting mechanisms are respectively arranged at the two ends of the frame, and the two limiting mechanisms are respectively abutted with the inner side wall of the U-shaped beam and move along the inner side wall.

Further, the limiting mechanism comprises a limiting frame and a guide wheel, wherein the limiting frame is fixed on the frame, the guide wheel is installed on the limiting frame, and the guide wheel is abutted to the inner side wall of the U-shaped beam and moves along the inner side wall.

Further, the limiting frame comprises a body, a U-shaped frame and an adjusting screw, the body is fixed on the frame, the guide wheel is installed at the bottom end of the U-shaped frame, the U-shaped frame is slidably connected with the body, and the adjusting screw penetrates through the end of the body and abuts against the U-shaped frame to adjust the distance between the guide wheel and the body.

Further, the limiting frame further comprises a plurality of bolts, waist holes are formed in two side walls of the U-shaped frame respectively, and each bolt penetrates through the waist hole to be abutted with the body and slide in the waist hole; the adjusting screw is in threaded connection with the end part of the body, and one end of the adjusting screw is in butt joint with the bottom wall of the U-shaped frame.

Further, the travelling mechanism comprises a first mechanism and a second mechanism, the first mechanism and the second mechanism are oppositely arranged at two ends of the frame, the first mechanism is hinged with the frame, and the second mechanism is in telescopic connection with the frame.

Further, the second mechanism comprises a travelling wheel, a wheel frame and a track-changing screw rod, wherein the travelling wheel is arranged at the bottom end of the wheel frame, and the wheel frame is telescopically inserted on the frame; one end of the track-changing screw rod penetrates through the wheel frame to be abutted with the frame, and the track-changing screw rod is in threaded connection with the wheel frame to adjust the distance between the travelling wheel and the frame.

Further, the second mechanism is provided with two travelling wheels and two orbital transfer screws, the two travelling wheels are respectively positioned at two end parts of the wheel frame, and each orbital transfer screw is respectively corresponding to one travelling wheel and positioned above the travelling wheel.

Further, the walking mechanism further comprises a driving part and a chain, and the output end of the driving part is connected with the first mechanism and the second mechanism through the chain respectively so as to drive the first mechanism and the second mechanism to move.

Further, the working vehicle comprises a guardrail, and the guardrail is mounted on the frame and arranged on one side or two sides of the driving part.

Further, the frame comprises two cross beams, longitudinal beams and side beams, wherein the two cross beams are oppositely arranged and transversely span the U-shaped beam, and the longitudinal beams are connected with the two cross beams; the outside of the cross beam is respectively provided with the side beams.

The working vehicle for the overhead U-shaped beam is provided with the hanging bracket mechanism, and the transportation of track laying materials and tools and the laying of precast slabs are realized through a plurality of hanging components on the hanging bracket mechanism; and set up two stop gear, install the both ends at the frame respectively, stop gear and the inside wall butt of U type roof beam just move along the inside wall to the running gear of restriction operation car removes along the U type roof beam, avoids the skew or the condition that drops. The working vehicle for the overhead U-shaped beam can realize mechanized construction of all types of ballast beds of the overhead U-shaped beam, and can improve the site construction progress and efficiency, including pouring construction of general ballast beds, installation and maintenance of precast slab ballast beds and the like; and through the setting of stop gear, can make the operation car keep walking along U type roof beam top.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.

FIG. 1 is a front view of an overhead U-beam work vehicle according to an embodiment of the present utility model;

FIG. 2 is a top view of an overhead U-beam work vehicle according to an embodiment of the present utility model;

FIG. 3 is a view showing a state of use of the overhead U-beam work vehicle according to the embodiment of the present utility model;

Fig. 4 is a schematic structural view of the limiting mechanism in fig. 1.

Reference numerals:

100. a frame; 110. a cross beam; 120. a longitudinal beam; 130. a side beam;

210. A first mechanism;

220. A second mechanism; 221. a walking wheel; 222. a wheel carrier; 223. a rail-changing screw;

300. a hanger mechanism; 310. a frame body; 320. hoisting the assembly;

400. A limiting mechanism; 411. a body; 412. a U-shaped frame; 412a, waist holes; 413. adjusting a screw; 414. a bolt; 420. a guide wheel;

500. A guardrail.

Detailed Description

In order to enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions of the embodiments of the present application will be clearly and completely described below, and it is obvious that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" or "a number" means two or more, unless specifically defined otherwise.

It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the application to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the application, are included in the spirit and scope of the application which is otherwise, without departing from the spirit or scope thereof.

As shown in fig. 1 and 2, the embodiment of the application provides an overhead U-shaped beam working vehicle, which comprises a frame 100, a travelling mechanism, a hanger mechanism 300 and a limiting mechanism 400, wherein the travelling mechanism is arranged on the frame 100 to drive the frame 100 to move, the hanger mechanism 300 comprises a frame body 310 and a hoisting assembly 320, the frame body 310 is fixed on the frame 100, at least two hoisting assemblies 320 are arranged on the frame body 310, and the two hoisting assemblies 320 are oppositely arranged in the width direction of the U-shaped beam; the number of the limiting mechanisms 400 is at least two, the two ends of the frame 100 are respectively provided with the limiting mechanisms 400, and the two limiting mechanisms 400 are respectively abutted with the inner side walls of the U-shaped beams and move along the inner side walls.

When the track is constructed on the overhead U-shaped beam, some projects have short track laying period, the working surface is discontinuous, a large amount of track laying materials need to be transported and moved on the bridge and are completed by manual or simple tools, and the later stage of track laying is performed manually, so that the efficiency is low; the precast slab track bed can be paved by the automobile crane under the condition that certain conditions allow, but many areas cannot be paved by using the automobile crane, and paving construction cannot be performed.

In the embodiment of the application, the hanger mechanism 300 is used for transferring and spreading rail laying materials, tools and the like, so that manual material transfer is avoided, and even the hanger mechanism can be directly used for laying precast slab track beds, and the laying efficiency is improved. Hanger mechanism 300 includes a frame body 310 and a plurality of lifting assemblies 320, frame body 310 being secured to frame 100 for providing stable support for lifting assemblies 320. The frame body 310 may be square steel, preferably two square steels, welded at two ends of the frame 100 respectively; a frame formed of square steel may be welded to the vehicle frame 100. Hoisting assemblies 320 are arranged at two ends of the square steel; or a plurality of hoist assemblies 320 are respectively mounted on a frame formed of square steel. The hanger mechanism 300 includes at least two hanging members 320 disposed opposite to each other in the width direction of the U-shaped beam, and can be used to hang rail laying materials or hang both sides of a prefabricated slab, respectively, so that hanging is more stable. The hoist assembly 320 may include an electric hoist and a connection member, through which the electric hoist is connected with the frame 310. The connecting piece is a hook or a clamping ring.

In the embodiment of the present application, referring to the usage state diagram of the working vehicle in fig. 3, the travelling mechanism drives the frame 100 to move on top of the U-beam, and at least two limiting mechanisms 400 can keep the working vehicle travelling along the U-beam, so as to avoid deviation or falling. The limiting mechanisms 400 are respectively disposed at two end portions of the frame 100, so as to be conveniently abutted on the inner side wall of the U-shaped beam, and the abutting positions of the limiting mechanisms 400 and the inner side wall can move along the inner side wall. That is, the stopper mechanism 400 can move in synchronization with the running mechanism and can avoid the displacement of the running mechanism. The number of the limit mechanisms 400 is at least two, so that the left-right offset of the travelling mechanism is avoided.

The overhead U-shaped beam working truck is provided with the hanging bracket mechanism 300, and the transportation of track laying materials and tools and the laying of precast slabs are realized through the plurality of hanging components 320 on the hanging bracket mechanism, so that the mechanized construction is realized, and the construction progress is accelerated; and set up two stop gear 400, install respectively at the both ends of frame 100, stop gear 400 and the inside wall butt of U type roof beam and follow the inside wall and remove to the running gear of restriction operation car removes along the U type roof beam, avoids the skew or the condition that drops. The working vehicle for the overhead U-shaped beam can realize mechanized construction of all types of ballast beds of the overhead U-shaped beam, and can improve the site construction progress and efficiency, including pouring construction of general ballast beds, installation and maintenance of precast slab ballast beds and the like; and by arranging the limiting mechanism 400, the operation vehicle can keep walking along the top of the U-shaped beam.

Specifically, referring to fig. 4, the limiting mechanism 400 includes a limiting frame and a guide wheel 420, the limiting frame is fixed on the frame 100, the guide wheel 420 is mounted on the limiting frame, and the guide wheel 420 is abutted with the inner side wall of the U-shaped beam and moves along the inner side wall. One end of the limiting frame is connected with the frame 100 through a bolt 414, and a guide wheel 420 is arranged at the other end of the limiting frame. The guide wheel 420 abuts the inner side wall of the U-beam to provide a guiding action for the work vehicle and moves with the travel mechanism.

In some embodiments, the limiting frame includes a body 411, a U-shaped frame 412 and an adjusting screw 413, the body 411 is fixed on the frame 100, the guide wheel 420 is mounted at the bottom end of the U-shaped frame 412, the U-shaped frame 412 is slidably connected with the body 411, and the adjusting screw 413 passes through the end of the body 411 to abut against the U-shaped frame 412 to adjust the distance between the guide wheel 420 and the body 411. One end of the body 411 is connected with the frame 100 by a bolt 414, and the other end is connected with the U-shaped frame 412 in a sliding manner, namely the U-shaped frame 412 can move at the end of the body 411. The guide wheel 420 is disposed on one side of the body 411 near the U-beam. The adjusting screw 413 is used for adjusting the distance between the guide wheel 420 and the body 411, i.e. the distance between the bottom of the U-shaped frame 412 and the body 411. For example, when the distance between the two guide wheels 420 in the width direction of the overhead U-shaped beam is increased, the distance between the guide wheels 420 and the body 411 needs to be increased, and at this time, the bottom of the U-shaped frame 412 is pushed by the adjusting screw 413, so that the U-shaped frame 412 moves at the end of the body 411, thereby increasing the distance between the U-shaped frame and the guide wheels 420 and satisfying the change of the distance between the U-shaped beam in the width direction.

Specifically, the limiting frame further includes a plurality of bolts 414, and waist holes 412a are formed on two sidewalls of the u-shaped frame 412, respectively, and each bolt 414 passes through the waist hole 412a to be abutted with the body 411 and slide in the waist hole 412 a. The adjusting screw 413 is screwed to the end of the body 411, and one end thereof abuts against the bottom wall of the U-shaped frame 412. The bolt 414 is abutted on the body 411 through the waist hole 412a, and the U-shaped frame 412 can slide along the waist hole 412a direction, so that the distance between the guide wheel 420 at the bottom end of the U-shaped frame 412 and the body 411 is increased or reduced, and even if the width of the U-shaped beam is changed, the operation vehicle can walk along the path of the U-shaped beam, and the walking safety is ensured. The adjusting screw 413 is screwed with the body 411, and at this time, the U-shaped frame 412 can be moved by rotating the adjusting screw 413. The non-operating end of the adjusting screw 413 abuts against the bottom wall of the U-shaped frame 412.

In some embodiments, the walking mechanism includes a first mechanism 210 and a second mechanism 220, where the first mechanism 210 and the second mechanism 220 are disposed at two ends of the frame 100, the first mechanism 210 is hinged to the frame 100, and the second mechanism 220 is telescopically connected to the frame 100. The first mechanism 210 and the second mechanism 220 are disposed opposite to each other on the frame 100. The first and second mechanisms 210, 220 cause the frame 100 to travel on the U-beam. The first mechanism 210 is hinged with the frame 100 to facilitate steering during walking, so as to be suitable for walking of the wall of the subway tunnel. The second mechanism 220 is telescopically connected with the frame 100, so that the distance between the travelling wheels 221 of the first mechanism 210 and the second mechanism 220 on the working vehicle can be adjusted, the track is changed, and the working vehicle is suitable for walking in different environments.

Specifically, the second mechanism 220 includes a traveling wheel 221, a wheel frame 222, and a track-changing screw 223, the traveling wheel 221 is mounted at the bottom end of the wheel frame 222, and the wheel frame 222 is telescopically inserted on the frame 100; one end of the track-changing screw 223 passes through the wheel frame 222 to be abutted with the frame 100, and the track-changing screw 223 is in threaded connection with the wheel frame 222 to adjust the distance between the travelling wheel 221 and the frame 100. In the embodiment of the application, the distance between the wheel frame 222 and the frame 100 is adjusted by the track-changing screw 223, so that the distance between the travelling wheels 221 on the working vehicle between the first mechanism 210 and the second mechanism 220 is adjusted. The threaded connection of the orbital transfer screw 223 and the wheel frame 222 converts the rotation of the screw into the linear movement of the wheel frame 222, and the manual rotation of the orbital transfer screw 223 can be realized, so that the operation is convenient.

In some embodiments, the second mechanism 220 is provided with two travelling wheels 221 and two orbital screws 223, the two travelling wheels 221 are respectively located at two ends of the wheel frame 222, and each orbital screw 223 is respectively corresponding to one travelling wheel 221 and located above the travelling wheel 221. It will be appreciated that the arrangement of the two orbital screws 223 can work together on the wheel frame 222, enabling a more effort-efficient adjustment of the distance of the wheel frame 222 from the frame 100. The first mechanism 210 is also provided with two road wheels 221. The first mechanism 210 and the second mechanism 220 are symmetrically arranged. For the road wheels 221, one road wheel 221 of the first mechanism 210 is a driving wheel, and the other road wheel 221 is a driven wheel; the second mechanism 220 is disposed identically to the first mechanism 210. In addition, the first mechanism 210 and the second mechanism 220 are respectively provided with a braking device, so that the working vehicle can be decelerated or stopped in the shortest distance as required, the parking braking effect is convenient, the working vehicle cannot slide down, and the safety of personnel in the construction process is protected.

In some embodiments, the walking mechanism further includes a driving portion and a chain, and the output end of the driving portion is connected to the first mechanism 210 and the second mechanism 220 through the chain to drive the first mechanism 210 and the second mechanism 220 to move. In the embodiment of the application, the driving part comprises a driving motor and a driving gear, and the driving gear is arranged at the output end of the driving motor. The first mechanism 210 and the second mechanism 220 are respectively provided with driven gears, and the driven gears are respectively connected with driving wheels of the traveling wheels 221. The driving gear drives the driven gear to rotate through the chain so as to drive the driving wheels of the travelling wheels 221 to rotate, and the movement of the working vehicle is realized. The driving motor adopts 2 motors of 50W G series of variable frequency speed regulation formulation, the motors are arranged on the frame 100, and the motors are fixedly connected with the frame 100 through bolts 414.

In some embodiments, the work vehicle includes a guard rail 500, the guard rail 500 being mounted on the frame 100 and disposed on one side of the drive portion. It will be appreciated that the guard rail 500 can provide convenience to operators and ensure personnel safety when the motor is in trouble shooting. The guard rail 500 is formed by welding round pipes. The guard rail 500 is connected to the frame 100 in a socket-and-spigot manner. Guard rails 500 may be provided on both sides of the driving part, respectively.

In some embodiments, the frame 100 includes two cross members 110, longitudinal beams 120 and side beams 130, the number of the cross members 110 is two, the two cross members 110 are oppositely arranged and span the U-shaped beam, and the longitudinal beams 120 connect the two cross members 110; the lateral beams 130 are provided on the outer sides of the cross member 110, respectively. The longitudinal beam 120 may be one or more, which is connected between the two cross members 110 to further stabilize the frame 100. The running gear is provided at an end of the beam 110. The cross member 110 and the side member 120 are made of square steel. In order to facilitate the maintenance and the operation of material hoisting, operation tables are arranged on two sides of the bearing part. The operator's station is a layer of steel plate welded to the cross member 110 and the longitudinal member 120. The side beams 130 are provided on the outer sides of the two cross beams 110 to facilitate placement of concrete hoppers, tanks, etc.

In addition, the work vehicle is provided with a control system including an electric box and a bracket, which is connected to the frame 100. The electric box is internally provided with a circuit control switch and a remote control device, and the running and hoisting of the operation vehicle are comprehensively controlled through the circuit switch and the remote control device. The working vehicle is further provided with a cable reel mounted on the frame 100, and the cable is wound and unwound by rotating the cable reel while the working vehicle is traveling. The cable is connected with the distribution box to provide power for walking, hoisting and transportation of the operation vehicle. The cable winding reel can be replaced by a storage battery power supply mode, new energy is utilized for charging, and the convenience of walking of the comprehensive operation vehicle is met.

The working vehicle disclosed by the embodiment of the application fully solves the problem of low material transfer efficiency of tools such as U-shaped Liang Daochuang precast slabs, reinforcing steel bars, templates, concrete, steel rails and the like, releases manpower, realizes mechanized construction and accelerates the site construction progress. The walking is simple and convenient, the factors influenced by the environment are small, the speed is high, and the efficiency is high; the operation is simple, the safety and reliability are high, the functions are perfect, and not only can the hoisting be realized, but also other tooling materials such as a hopper, a water tank and the like can be placed.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The utility model provides an overhead U type operation car for roof beam which characterized in that: the lifting frame mechanism comprises a frame, a travelling mechanism, a lifting frame mechanism and a limiting mechanism, wherein the travelling mechanism is arranged on the frame to drive the frame to move, the lifting frame mechanism comprises a frame body and lifting components, the frame body is fixed on the frame, at least two lifting components are arranged on the frame body, and the two lifting components are oppositely arranged in the width direction of a U-shaped beam; the number of the limiting mechanisms is at least two, the limiting mechanisms are respectively arranged at the two ends of the frame, and the two limiting mechanisms are respectively abutted with the inner side wall of the U-shaped beam and move along the inner side wall.

2. The overhead U-beam work vehicle of claim 1 wherein the spacing mechanism includes a spacing and a guide wheel, the spacing being fixed to the frame, the guide wheel being mounted to the spacing, the guide wheel being in abutment with and moving along the inner side wall of the U-beam.

3. The overhead working truck for the U-shaped beam according to claim 2, wherein the limiting frame comprises a body, a U-shaped frame and an adjusting screw, the body is fixed on the frame, the guide wheel is installed at the bottom end of the U-shaped frame, the U-shaped frame is slidably connected with the body, and the adjusting screw passes through the end of the body and abuts against the U-shaped frame to adjust the distance between the guide wheel and the body.

4. The overhead working truck for the U-shaped beam according to claim 3, wherein the limiting frame further comprises a plurality of bolts, waist holes are respectively formed on two side walls of the U-shaped frame, and each bolt passes through the waist hole to be abutted with the body and slides in the waist hole; the adjusting screw is in threaded connection with the end part of the body, and one end of the adjusting screw is in butt joint with the bottom wall of the U-shaped frame.

5. The overhead U-beam work vehicle of any one of claims 1 to 4 wherein the travelling mechanism includes a first mechanism and a second mechanism, the first mechanism and the second mechanism being disposed opposite the ends of the frame, the first mechanism being hinged to the frame, the second mechanism being telescopically coupled to the frame.

6. The overhead U-beam work vehicle of claim 5 wherein the second mechanism includes a road wheel, a wheel frame and a track change screw, the road wheel being mounted to the bottom end of the wheel frame, the wheel frame being telescopically received on the frame; one end of the track-changing screw rod penetrates through the wheel frame to be abutted with the frame, and the track-changing screw rod is in threaded connection with the wheel frame to adjust the distance between the travelling wheel and the frame.

7. The overhead U-beam working truck according to claim 6, wherein the second mechanism is provided with two traveling wheels and two orbital transfer screws, the two traveling wheels are respectively located at two ends of the wheel frame, and each orbital transfer screw is respectively located corresponding to one traveling wheel and above the traveling wheel.

8. The overhead U-beam working truck according to claim 5, wherein the travelling mechanism further comprises a driving part and a chain, and the output end of the driving part is connected with the first mechanism and the second mechanism through the chain to drive the first mechanism and the second mechanism to move.

9. The overhead U-beam work vehicle of claim 8 wherein the work vehicle includes a rail mounted to the frame and disposed on one or both sides of the drive section.

10. The working vehicle for an overhead U-shaped beam according to any one of claims 1 to 4, wherein the frame includes two cross members, a longitudinal member and a side member, the two cross members are disposed opposite to each other and transversely across the U-shaped beam, and the longitudinal member connects the two cross members; the outside of the cross beam is respectively provided with the side beams.