CN207389403U - Scooter - Google Patents

Abstract

The utility model discloses a kind of scooters, including beat and steering mechanism, stage casing vehicle frame, driving wheel, two front-wheels, the beat and steering mechanism are arranged at the front end of the stage casing vehicle frame, described two front-wheels are connected with the beat and steering mechanism and are symmetrically arranged at left and right sides of the front end of the stage casing vehicle frame, and using the stage casing vehicle frame as symmetry axis, the driving wheel is arranged at the rear end of back segment vehicle frame, and back segment vehicle frame is arranged on the rear end of the stage casing vehicle frame and back segment damping is equipped between back segment vehicle frame and stage casing vehicle frame；The free end of the supporting beam is hinged by the front end of articulated shaft and stage casing vehicle frame, and the top of beam accessory body is connected by adjusting fixed mechanism with stage casing vehicle frame.The scooter of the utility model, overall structure is simple, easily manufactured, reduces the thickness of stage casing vehicle frame, reduces the running center of gravity of vehicle, improves the stationarity of driver in motion.

Description

Scooter

Technical field

The utility model is related to a kind of vehicles, and in particular to a kind of scooter.

Background technology

Existing scooter on the market is usually two wheel scooters, and there is following defects for two wheel scooters：1st, the balance palm Hold that difficulty is high, pedal position is higher, this causes user when riding, and whole center of gravity is higher, this so that riding stability is bad, Driver, which easily occurs to break away, to be fallen down；2nd, front frame can not realize foldable integral；3rd, the damping effect of vehicle is poor.

The content of the invention

The technical problem to be solved by the utility model is to provide a kind of scooters, it can solve current scooter traveling Stability is poor, can not foldable integral, the problem of damping effect is poor.

In order to solve the above technical problems, the technical solution of the utility model scooter is：

Including beat and steering mechanism, stage casing vehicle frame, driving wheel, two front-wheels, the beat and steering mechanism are arranged at The front end of the stage casing vehicle frame, described two front-wheels connect with the beat and steering mechanism and are symmetrically arranged on the stage casing At left and right sides of the front end of vehicle frame, and using the stage casing vehicle frame as symmetry axis, the driving wheel is arranged at the rear end of back segment vehicle frame, after Section vehicle frame is arranged on the rear end of the stage casing vehicle frame and back segment damping is equipped between back segment vehicle frame and stage casing vehicle frame；

The beat and steering mechanism include front section bicycle frame and the left forearm for being symmetrically disposed on the front section bicycle frame both sides Component, right forearm component,

The left front arm component includes upper left rocking arm, lower left swing arm and left steering section, the first end of the upper left rocking arm, a left side The first end of lower shake-changing arm is hinged respectively by the first pivot, the second pivot and the front section bicycle frame, and the upper left is shaken Arm, the second end of lower left swing arm pass through the first spherical plain bearing rod end, the second spherical plain bearing rod end and the left steering section respectively Top, lower hinge, first pivot, the shaft of the second pivot are perpendicular to same plane；

The right forearm component includes upper right rocking arm, lower right swing arm and right turn section, the first end of the upper right rocking arm, the right side The first end of lower shake-changing arm is hinged respectively by the 3rd pivot, the 4th pivot and the front section bicycle frame, and the upper right is shaken Arm, the second end of lower right swing arm pass through the 3rd spherical plain bearing rod end, the 4th spherical plain bearing rod end and the right turn section respectively Top, lower hinge, the 3rd pivot, the shaft of the 4th pivot are perpendicular to same plane；

Leading portion damping is equipped between the upper left rocking arm and upper right rocking arm；

The beat and steering mechanism further include a steering structure, and the steering structure includes being fixed on front section bicycle frame Front steering column sleeve, the side wall of front steering column through front steering column sleeve and front steering column are extended with connecting rod, connecting rod Be connected on the axle bed of universal steering machine structure, the left end of the universal steering machine structure, right end respectively with mounted on left steering section 5th spherical plain bearing rod end of front end, the 6th spherical plain bearing rod end connection of the front end of right turn section；The front steering column Upper end is equipped with handlebar；

The front section bicycle frame includes girder, and the girder includes D type beam main bodys and beam accessory body, and D type beams main body has bottom Longitudinal extension one and bottom longitudinal extension two, are additionally provided with mounting hole in the D types beam main body, the mounting hole by upper hole with Lower opening forms, and first end, the first end of upper right rocking arm of the upper left rocking arm are arranged in lower opening, and leading portion damping is arranged in Upper hole；The first end of the lower left swing arm, the first end of lower right swing arm are arranged on bottom longitudinal extension one and longitudinally prolong with bottom It stretches between section two；The beam accessory body is in the upper rear end of D type beam main bodys, and is connected with branch in the rear end lower of D type beam main bodys Support beam；

The free end of the supporting beam is hinged by the front end of articulated shaft and stage casing vehicle frame, and the top of beam accessory body passes through adjusting Fixed mechanism is connected with stage casing vehicle frame, so that front end vehicle frame can be rotated or fixed compared with the stage casing vehicle frame；The tune Saving fixed mechanism includes first support bar, second support bar and lock, and the first support bar is inserted in second support bar In heart hole, and first support bar can move back and forth in centre bore along axis；The free end of the first support bar and stage casing vehicle Frame is hinged, and free end and the front section bicycle frame of second support bar are hinged.

The back segment damping includes the fixed pressing plate in front end with back segment vehicle frame, the support being fixed on the vehicle frame of stage casing Plate and the damping spring between pressing plate and support plate, fixing axle perforation stage casing vehicle frame, back segment vehicle frame and pressing plate, So that back segment vehicle frame is hinged with respect to stage casing vehicle frame, and damping spring has upward active force always to pressing plate.

The stage casing vehicle frame includes left stay tube, right stay tube, the left stay tube of connection and the middle stay tube and pedal of right stay tube, institute It states and battery accommodating groove is formd between left stay tube and right stay tube, battery case is installed in battery accommodating groove, the battery case includes Box body is arranged on the in vivo battery pack of box, and the battery pack includes several battery units, and several battery units assume diamond in shape array row Cloth.

The left stay tube, right stay tube, back segment vehicle frame, supporting beam are section bar, and structure is consistent, including rectangular main body, Semicircular ring of the main body wherein one with respect to both sides is arranged on, the main body is integrally formed with semicircular ring.

The beat and steering mechanism further include hub unit, and the hub unit, which is sheathed on the knuckle, installs wheel The axis of hub is arranged with bearing on the axis, and bearing is embedded in the axis hole of knuckle.

The beat and steering mechanism further include hub unit, and the hub unit is arranged on the knuckle and installs wheel hub Axis, the axis is fixed on knuckle, bearing is arranged on axis, hub unit is set in bearing outer wall.

The beam accessory body is connected to the upper rear end of D type beam main bodys by joinery and its construction, in the rear end lower of D type beam main bodys Section two is extended laterally equipped with Duan Yiyu is extended laterally, described extend laterally between Duan Yiyu extends laterally section two forms accommodating sky Between, inserted block is equipped in accommodating space, the supporting beam is arranged in accommodating space, and is equipped with and inserted block in the front end of supporting beam The slot matched somebody with somebody；The supporting beam is equipped with welding hole, and welding hole matching is in the outer edge position of inserted block, can be with by welding hole The interior welds of inserted block and supporting beam are integrated；By to seam crossing, supporting beam and the D type beams between beam accessory body and supporting beam The seam crossing and inserted block of main body and the welding inside supporting beam, so as to the beam accessory body and supporting beam and D type beam main bodys Realize high intensity connection.Split designs, and reduces the size of mold, reduces die cost, meanwhile, it ensure that the carrying of girder Intensity.

Several hollow outs are equipped in the beam accessory body.

The D types beam main body is an integral molding structure with beam accessory body.

First end, the first end of lower left swing arm of the upper left rocking arm are equipped with U-shaped pivotal arm, and the first of upper right rocking arm End, the first end of lower right swing arm are embedded respectively in the U-shaped opening of the U-shaped pivotal arm in upper left rocking arm, lower left swing arm.

What the utility model can reach has the technical effect that：

The main load-carrying members of the unitized frame of the utility model are one-time formed section bar, alleviate the weight of vehicle, special The main beam structure not designed so that the bearing strength of vehicle improves, meanwhile, the hollow out design of beam accessory body alleviates weight, simplifies Manufacturing process, meanwhile, it, can be by D type beam main bodys, beam accessory body and supporting beam separate machined in order to further reduce production cost；

The utility model is equipped with leading portion damping and back segment damping, improves the traveling damping performance of vehicle；

The beat of the utility model and steering mechanism, the battery pack of diamond shape array distribution reduce the thickness of stage casing vehicle frame, The running center of gravity of vehicle is reduced, improves the stationarity of driver in motion；

The upper right rocking arm of the utility model（Lower right swing arm）First end is in upper left rocking arm（Lower left swing arm）First end it is U-shaped Layout type in the U-shaped opening of pivotal arm improves vehicle when driving, stability of strutting system of the rocking arm in beat.

Description of the drawings

The utility model is described in further detail with reference to the accompanying drawings and detailed description：

Fig. 1 is the stereoscopic schematic diagram of an angle of the utility model scooter；

Fig. 2 is the stereoscopic schematic diagram of another angle of the utility model scooter；

Fig. 3 is the three-dimensional exploded view of the utility model scooter；

Fig. 4 is the sectional view under the non-folded state of the utility model scooter；

Fig. 5 is the sectional view under the folded state of the utility model scooter；

Fig. 6 is the structure diagram of the section bar of the utility model scooter；

Fig. 7 is the structure diagram of the front end vehicle frame of the utility model scooter；

Fig. 8 is the structure diagram between the upper left rocking arm of the utility model scooter and upper right rocking arm；

Fig. 9 is the structure diagram of the embodiment one of the hub unit of the utility model scooter；

Figure 10 is the structure diagram of the embodiment two of the hub unit of the utility model scooter.

Specific embodiment

As shown in Figures 1 to 10, the utility model scooter, including beat and steering mechanism 1, stage casing vehicle frame 2, driving wheel 3rd, two front-wheels 4, the beat and steering mechanism 1 are arranged at the front end of the stage casing vehicle frame 2, described two front-wheels 4 and described Beat and steering mechanism 1 connect and are symmetrically arranged at left and right sides of the front end of the stage casing vehicle frame 2, and with the stage casing vehicle frame 2 be symmetry axis, and the driving wheel 3 is arranged at the rear end of back segment vehicle frame 5, and back segment vehicle frame 5 is arranged on the rear end of the stage casing vehicle frame 2 And back segment damping 6 is equipped between back segment vehicle frame 5 and stage casing vehicle frame 2；

The beat and steering mechanism 1 include front section bicycle frame 7 and are symmetrically disposed on a left side for 7 both sides of front section bicycle frame Forearm component, right forearm component,

The left front arm component include upper left rocking arm 8, lower left swing arm 9 and left steering section 10, the first of the upper left rocking arm 8 End, the first end of lower left swing arm 9 are hinged by the first pivot 11, the second pivot 12 and the front section bicycle frame 7 respectively, The upper left rocking arm 8, the second end of lower left swing arm 9 pass through the first spherical plain bearing rod end 13, the second spherical plain bearing rod end 14 respectively Top, lower hinge with the left steering section 10, first pivot 11, the second pivot 12 shaft perpendicular to Same plane；

The right forearm component includes upper right rocking arm 16, lower right swing arm 17 and right turn section 18, the upper right rocking arm 16 First end, the first end of lower right swing arm 17 pass through the 3rd pivot 19, the 4th pivot 20 and the front section bicycle frame 7 respectively Hinged, the upper right rocking arm 16, the second end of lower right swing arm 17 pass through the 3rd spherical plain bearing rod end 21, the 4th rod end joint respectively The top of bearing 22 and the right turn section 18, lower hinge, the 3rd pivot 19, the shaft of the 4th pivot 20 Perpendicular to same plane；

Leading portion damping 23 is equipped between the upper left rocking arm 8 and upper right rocking arm 16；

The beat and steering mechanism 1 further include a steering structure, and the steering structure includes being fixed on front section bicycle frame 7 Front steering column sleeve 25, the side wall of front steering column 26 through front steering column sleeve 25 and front steering column 26 is extended with Connecting rod 27, connecting rod 27 are connected on the axle bed 28 of universal steering machine structure, the left end of the universal steering machine structure, right end respectively with peace 6th spherical plain bearing rod end 30 of the front end of the 5th spherical plain bearing rod end 29, right turn section 18 mounted in the front end of left steering section 10 Connection；The upper end of the front steering column 26 is equipped with handlebar 32；

The front section bicycle frame 7 includes girder 61, and the girder 61 includes D type beams main body 62 and beam accessory body 63, D type beam main bodys 62 have bottom longitudinal extension 1 and bottom longitudinal extension 2 65, and mounting hole 66 is additionally provided in the D types beam main body 62, The mounting hole 66 is made of upper hole 67 with lower opening 68, and first end, the first end of upper right rocking arm 16 of the upper left rocking arm 8 are set In lower opening 68, leading portion damping 23 is arranged in hole 67；The first end of the lower left swing arm 9, the first of lower right swing arm 17 End is arranged between bottom longitudinal extension 1 and bottom longitudinal extension 2 65；The beam accessory body 63 is in D type beam main bodys 62 upper rear end, and it is connected with supporting beam 69 in the rear end lower of D type beams main body 62；

The free end of the supporting beam 69 is hinged by articulated shaft 70 and the front end of stage casing vehicle frame 2, the top of beam accessory body 63 It is connected by adjusting fixed mechanism 34 with stage casing vehicle frame 2, so that front section bicycle frame 7 can be rotated compared with the stage casing vehicle frame 2 It is or fixed；The adjusting fixed mechanism 34 includes first support bar 35, second support bar 36 and lock 37, the first support bar 35 are inserted in the centre bore of second support bar 36, and first support bar 35 can move back and forth in centre bore along axis；It is described The free end of first support bar 35 is hinged with stage casing vehicle frame 2, and the free end of second support bar 36 and front section bicycle frame 7 are hinged.

The back segment damping 6 include with the fixed pressing plate 38 in front end of back segment vehicle frame 5, be fixed on stage casing vehicle frame 2 Support plate 39 and the damping spring 40 between pressing plate 38 and support plate 39, a fixing axle 71 perforation stage casing vehicle frame 2, Back segment vehicle frame 5 and pressing plate 38 so that back segment vehicle frame 5 is hinged with respect to stage casing vehicle frame 2, and damping spring 40 to pressing plate 38 always With upward active force.

Middle stay tube 43 of the stage casing vehicle frame 2 including left stay tube 41, right stay tube 42, the left stay tube 41 of connection and right stay tube 42, And pedal 44, battery accommodating groove 45 is formd between the left stay tube 41 and right stay tube 42, is equipped in battery accommodating groove 45 Battery case 46, the battery case 46 includes box body 47, the battery pack being arranged in box body 47, if the battery pack includes dry cell Unit 49, several battery units 49 assume diamond in shape array arrangement.

The left stay tube 41, right stay tube 42, back segment vehicle frame 5, supporting beam 69 are section bar, and structure is consistent, including rectangular Main body 50, be arranged on semicircular ring 51 of the main body 50 wherein one with respect to both sides, the main body 50 is integrally formed with semicircular ring 51. In application process, the pedal 44 of stage casing vehicle frame 2 is supported in semicircular ring 51, according to the stronger principle of domes support force, Improve vehicle frame integrated carrying ability and the distortion resistance of vehicle frame simultaneously.

The tool of girder 61 is there are two types of processing method, and one kind is split structure, and this processing method can substantially reduce mold Cost, be specially：

The beam accessory body 63 is connected to the upper rear end of D type beams main body 62 by joinery and its construction 73, in D type beams main body 62 Rear end lower, which is equipped with, to be extended laterally section 1 and extends laterally section 2 75, described to extend laterally section 1 and extend laterally section 2 75 Between form accommodating space, inserted block 76 is equipped in accommodating space, the supporting beam 69 is arranged in accommodating space, and is supporting The front end of beam 69 be equipped with 76 matched slot 77 of inserted block, since supporting beam 69 has rectangular main body 50 and is arranged on 51 structure of semicircular ring on the opposite both sides of main body 50 wherein one, so, the actual rectangular body 50 for section bar of slot 77 is interior herein Hole；The supporting beam 69 is equipped with welding hole 78, and welding hole 78 matched in the outer edge position of inserted block 76, by welding hole 78, Inserted block 76 and the interior welds of supporting beam 69 can be integrated；By between beam accessory body 63 and supporting beam 69 seam crossing, The seam crossing, inserted block 76 and the welding at 69 inside of supporting beam and joinery and its construction 73 of supporting beam 69 and D type beams main body 62, so as to High intensity, which is connected, to be realized with supporting beam 69 and D type beams main body 62 to the beam accessory body 63.D type beams main body 62, beam accessory body 63 Split designs, and reduces the size of mold, reduces die cost, meanwhile, it ensure that the bearing strength of girder 61.

Another kind is that D type beams main body 62 is an integral molding structure with beam accessory body 63, this undoubtedly absolute guarantee in structure Intensity.

In order to mitigate the weight of girder 61, several hollow outs 79 are especially set in beam accessory body 63.

First end, the first end of lower left swing arm 9 of the upper left rocking arm 8 are equipped with U-shaped pivotal arm 80, upper right rocking arm 16 First end, the first end of lower right swing arm 17 are embedded the U-shaped opening of the U-shaped pivotal arm 80 in upper left rocking arm 8, lower left swing arm 9 respectively In 81.This layout type improves vehicle when driving, stability of strutting system of the rocking arm in beat, meanwhile, reduce bearing Usage amount reduces cost.

There are two types of the mounting structure tools of the hub unit of the scooter of the utility model, specific as follows：

Embodiment one, without brake disc version.Referring to Fig. 6, the beat and steering mechanism 1 further include hub unit 52, The hub unit 52 is sheathed on the axis 54 that wheel hub is installed on the knuckle 53, and bearing 55, bearing are arranged on the axis 54 55 are embedded in the axis hole 56 of knuckle 53.

Embodiment two has brake disc version.Referring to Fig. 7, the beat and steering mechanism 1 further include hub unit 57, The hub unit 57 is arranged on the knuckle 58 axis 59 for installing wheel hub, and the axis 59 is fixed on knuckle 58, in axis Bearing 60 is arranged on 59, hub unit 57 is set in 60 outer wall of bearing.

The scooter provided above the utility model embodiment is described in detail, used herein specifically a Example is set forth the principle and embodiment of the utility model, and the explanation of above example is only intended to help to understand this reality With new revealed technical solution；Meanwhile for those of ordinary skill in the art, according to the thought of the utility model, There will be changes in specific embodiment and application range, in conclusion this specification content should not be construed as this practicality New limitation.

Claims (10)

1. a kind of scooter, it is characterised in that：It is described including beat and steering mechanism, stage casing vehicle frame, driving wheel, two front-wheels Beat and steering mechanism are arranged at the front end of the stage casing vehicle frame, and described two front-wheels connect simultaneously with the beat and steering mechanism It is symmetrically arranged at left and right sides of the front end of the stage casing vehicle frame, and using the stage casing vehicle frame as symmetry axis, the driving wheel is set The rear end of back segment vehicle frame is placed in, back segment vehicle frame is arranged on the rear end of the stage casing vehicle frame and between back segment vehicle frame and stage casing vehicle frame Equipped with back segment damping；

The beat and steering mechanism include front section bicycle frame and the left forearm group for being symmetrically disposed on the front section bicycle frame both sides Part, right forearm component,

The left front arm component includes upper left rocking arm, lower left swing arm and left steering section, and the first end of the upper left rocking arm, lower-left are shaken The first end of arm is hinged respectively by the first pivot, the second pivot and the front section bicycle frame, the upper left rocking arm, a left side The second end of lower shake-changing arm respectively by the first spherical plain bearing rod end, the second spherical plain bearing rod end and the left steering section top, Lower hinge, first pivot, the shaft of the second pivot are perpendicular to same plane；

The right forearm component includes upper right rocking arm, lower right swing arm and right turn section, and the first end of the upper right rocking arm, bottom right are shaken The first end of arm is hinged respectively by the 3rd pivot, the 4th pivot and the front section bicycle frame, the upper right rocking arm, the right side The second end of lower shake-changing arm respectively by the top of the 3rd spherical plain bearing rod end, the 4th spherical plain bearing rod end and the right turn section, Lower hinge, the 3rd pivot, the shaft of the 4th pivot are perpendicular to same plane；

Leading portion damping is equipped between the upper left rocking arm and upper right rocking arm；

The beat and steering mechanism further include a steering structure, and the steering structure includes the forward being fixed on front section bicycle frame To column sleeve, the side wall of front steering column through front steering column sleeve and front steering column is extended with connecting rod, connecting rod connection On the axle bed of universal steering machine structure, the left end of the universal steering machine structure, right end respectively with mounted on the front end of left steering section The 5th spherical plain bearing rod end, right turn section front end the 6th spherical plain bearing rod end connection；The upper end of the front steering column Equipped with handlebar；

The front section bicycle frame includes girder, and the girder includes D type beam main bodys and beam accessory body, and D type beams main body has bottom longitudinal direction Extended segment one and bottom longitudinal extension two are additionally provided with mounting hole in the D types beam main body, and the mounting hole is by upper hole and lower opening Composition, first end, the first end of upper right rocking arm of the upper left rocking arm are arranged in lower opening, and leading portion damping is arranged in Hole；The first end of the lower left swing arm, the first end of lower right swing arm are arranged on bottom longitudinal extension one and bottom Longitudinal extending Between section two；The beam accessory body is in the upper rear end of D type beam main bodys, and is connected with support in the rear end lower of D type beam main bodys Beam；

The free end of the supporting beam is hinged by the front end of articulated shaft and stage casing vehicle frame, and the top of beam accessory body is fixed by adjusting Mechanism is connected with stage casing vehicle frame, so that front end vehicle frame can be rotated or fixed compared with the stage casing vehicle frame；It is described to adjust admittedly Determining mechanism includes first support bar, second support bar and lock, and the first support bar is inserted in the centre bore of second support bar It is interior, and first support bar can move back and forth in centre bore along axis；It is cut with scissors with stage casing vehicle frame the free end of the first support bar It connects, free end and the front section bicycle frame of second support bar are hinged.

2. scooter according to claim 1, it is characterised in that：The back segment damping include with before back segment vehicle frame Fixed pressing plate, the support plate being fixed on the vehicle frame of stage casing and the damping spring between pressing plate and support plate are held, one is solid Dead axle perforation stage casing vehicle frame, back segment vehicle frame and pressing plate, so that back segment vehicle frame is hinged with respect to stage casing vehicle frame, and damping spring pair Pressing plate has upward active force always.

3. scooter according to claim 1, it is characterised in that：The stage casing vehicle frame includes left stay tube, right stay tube, connection The middle stay tube and pedal of left stay tube and right stay tube, form battery accommodating groove between the left stay tube and right stay tube, battery holds It puts and battery case is installed in slot, the battery case includes box body, is arranged on the in vivo battery pack of box, and the battery pack includes several Battery unit, several battery units assume diamond in shape array arrangement.

4. scooter according to claim 3, it is characterised in that：The left stay tube, right stay tube, back segment vehicle frame, supporting beam For section bar, and structure is consistent, including rectangular main body, is arranged on semicircular ring of the main body wherein one with respect to both sides, the main body It is integrally formed with semicircular ring.

5. scooter according to claim 1, it is characterised in that：The beat and steering mechanism further include hub unit, The hub unit is sheathed on the axis that wheel hub is installed on the knuckle, is arranged with bearing on the axis, bearing, which is embedded, to be turned to In the axis hole of section.

6. scooter according to claim 1, it is characterised in that：The beat and steering mechanism further include hub unit, The hub unit is arranged on the knuckle axis for installing wheel hub, and the axis is fixed on knuckle, and axis is arranged on axis It holds, hub unit is set in bearing outer wall.

7. scooter according to claim 1, it is characterised in that：The beam accessory body is connected to D type beams by joinery and its construction The upper rear end of main body is equipped in the rear end lower of D type beam main bodys and extends laterally Duan Yiyu and extend laterally section two, and the transverse direction is prolonged It stretches between Duan Yiyu extends laterally section two and forms accommodating space, inserted block is equipped in accommodating space, the supporting beam, which is arranged on, to be held In emptying, and it is equipped with and the matched slot of inserted block in the front end of supporting beam；The supporting beam is equipped with welding hole, welding hole The outer edge position of inserted block is fitted over, by welding hole, the interior welds of inserted block and supporting beam can be integrated.

8. scooter according to claim 7, it is characterised in that：Several hollow outs are equipped in the beam accessory body.

9. scooter according to claim 1, it is characterised in that：The D types beam main body and beam accessory body are integrally formed knot Structure.

10. scooter according to claim 1, it is characterised in that：The first end of the upper left rocking arm, the of lower left swing arm One end is equipped with U-shaped pivotal arm, and the first end of upper right rocking arm, the first end of lower right swing arm are embedded respectively in upper left rocking arm, lower-left In the U-shaped opening of the U-shaped pivotal arm of rocking arm.