CN112572653A

CN112572653A - Anti-falling device modified from middle support

Info

Publication number: CN112572653A
Application number: CN202110133074.2A
Authority: CN
Inventors: 刘淑林
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-02-01
Filing date: 2021-02-01
Publication date: 2021-03-30

Abstract

A fall-down prevention device modified by a middle support structurally comprises a shared rear wheel brake handle, an additional traction line, a newly-added traction line fixing frame and the modified middle support which are matched and connected; the outside at rear wheel brake handle is connected the trailing arm respectively and another section drum head locating plate, link the mount below the floorbar of electric motor car, at another section drum head locating plate, connect the pull wire between the mount, the pull wire links to each other back and sharing rear wheel brake handle formation link gear through triangle rope and well centre support, when the rear wheel emergency brake, drive the trailing arm through the pull wire by sharing rear wheel brake handle, support in the triangle rope pulling and do the slope after rotatory downwards, the downward sloping of well support makes two truckles of setting below well support ground connection in step, two truckles of ground connection play the effect of support to the balance when the automobile body emergency brake.

Description

Anti-falling device modified from middle support

Technical Field

The utility model provides a prevent falling down device by well support transformation system, belongs to two-wheeled electric motor car, motorcycle technical improvement's supporting technical field.

Background

The electric bicycle is an individual household engaged in electric bicycle and motorcycle repair work for many years, and the electric bicycle and the motorcycle with two wheels are frequently ridden at ordinary times; the phenomenon that the rear wheel can slide transversely to cause the left and right swinging of a vehicle body is easy to occur if the rear wheel brakes suddenly (because the front wheel can not brake at the moment, a greater accident that the vehicle turns over is easily caused) after the running speed of the existing two-wheel electric vehicle and motorcycle exceeds 25 kilometers is found, and the swinging phenomenon of the twisted hip of the vehicle body is more serious if the vehicle speed is higher, so that the accident potential that the vehicle is easy to fall down is brought to normal riding trip; particularly, accidents of falling injury are frequent for small brows which are delivered for taking out; in view of the above, i think that the technical means are needed to overcome the defects, so as to generate innovative inspiration (motivation), and particularly propose an anti-falling device modified from a middle support.

Disclosure of Invention

The invention aims to provide a falling-down prevention device modified from a middle support, so that the accident potential caused by the fact that a two-wheeled electric vehicle and a motorcycle in the prior art are easy to fall down when emergency braking is carried out is eliminated;

the structure of the device is formed by connecting a shared rear wheel brake handle, an additional traction wire, a newly-added traction wire fixing frame and a modified middle support in a matching way;

the shared rear wheel brake handle is formed by modifying an existing rear wheel brake handle (the shared rear wheel brake handle is called as a shared brake handle because the rear wheel brake handle has two functions), and the technical means adopted by the modified shared rear wheel brake handle is as follows: the outside of the rear wheel brake handle is connected with a section of traction arm (namely a rocker arm), the traction arm is made of a steel plate, the traction arm and the rear wheel brake handle made of steel are welded and connected into a whole, and the welded traction arm and the rear wheel brake handle are on the same plane; the outer end (the side close to the handlebar is the inner) of the traction arm is provided with a clamping groove connected with the cord end of the brake cord, and the clamping groove is structurally used for connecting the traction arm with one end of a joint of the cord in another traction cord; the length of the traction arm can meet the requirement that two trundles in a support during traction touch the ground when a rear wheel emergency brake is operated (when a brake handle is pinched), so that the swinging phenomenon that the hip of a vehicle body is twisted when the electric vehicle is subjected to emergency brake on the rear wheel is overcome;

another section of drum head positioning plate is connected to the drum head positioning plate which is used for fixing one end of the drum head of the rear wheel brake cable, and the other section of drum head positioning plate is formed by cutting (removing the annular sleeve part fixed on the handlebar, and increasing the length if the length is not enough) the drum head positioning plate; the other section of drum head positioning plate is connected with the existing drum head positioning plate for fixing one end of the rear wheel brake line drum head into a whole in a welding way; the length of the other section of drum head positioning plate after welding is matched with the length of a traction arm (rocker arm), and the other section of drum head positioning plate is used for fixing one end of a drum head of another traction wire; thus, the remanufacturing feature of the brake lever on the handlebar is formed (i.e., the remanufacturing feature on the handlebar is finished);

the following is to reform transform the automobile body of electric motor car, and the part of reforming transform is: a drum head positioning plate, namely a fixing frame, is additionally arranged below a bottom beam of the electric vehicle, the fixing frame is formed by modifying a lower fixing positioning plate in a rear wheel brake in the prior art, a plate body of the modified fixing frame is made into a right-angled trapezoid, and the fixing frame and a middle girder of a vehicle body are vertically welded and connected into a whole; the fixed frame is used for installing and fixing the lower end of another traction line; thus, the related remanufacturing characteristics of the body of the electric vehicle are formed (finished);

the following is to install another traction line: the other traction line is a brake line matched with the vehicle (the front and the rear brake lines can be used after being modified, and the length is long enough), the traction line is laid on the vehicle body along a section of path of the rear wheel brake line, and the drum heads (the drum heads at the two ends are different in shape) of the outer leather tubes at the two ends of the traction line are respectively connected with the other drum head positioning plate and the fixing frame into a whole; two ends of a cord in the outer sheath tube of the traction wire are respectively fixedly connected with the clamping groove in the traction arm and the middle part of the triangular rope into a whole; thus, a remanufacturing feature of an additional pull wire is formed; namely the installation process of an additional traction line is completed;

the following is a modification of the centering support: the bottom end of the middle support is modified, the bottoms of two bottom legs of the middle support are respectively cut off (only one caster is shown for comparison in the figure), the casters are respectively arranged below the cut-off end surfaces, and the caster frames of the casters and the bottoms of the two bottom legs of the middle support are respectively welded and connected into a whole; the length of the two bottom legs of the middle support after the caster is welded is equal to the length of the bottom legs before the caster is not cut off; therefore, the original use function of the middle support is ensured to be unchanged;

the inner sides of the two caster frames are respectively provided with a damper, one end of the wheel shaft of the caster is inserted into the shaft hole of the damper and then connected into a whole, and the shell of the damper and the caster frames are fixedly connected into a whole; so that the caster wheel and the damper are installed and connected into a whole; the mounted damper is used for controlling the flexible rotation of the caster and making resistance for the rotation of the caster; therefore, the phenomenon that the caster wheels slide due to uneven terrain when the middle support is used for supporting the vehicle body and parking is prevented; when the caster brakes and lands, the friction resistance with the ground is generated, and the caster maintains the balance of the vehicle body when braking and also helps to improve the braking effect of the brake; therefore, the damper on the caster has double functions of parking and braking the electric vehicle;

secondly, two bottom legs of the middle support are reformed: the adopted technical means is as follows: two bottom legs of the middle support are symmetrically drilled with a through hole respectively, and the through holes are positioned above the middle position of the length of the bottom legs; the through hole is used for penetrating the triangular rope and realizing the connection with a cord of another traction line; therefore, the structural characteristics of the caster, the damper and the through hole are added in the modified middle support, and the modification of the middle support is finished;

the connection of another traction line and the middle support is as follows: the adopted technical means is as follows: an additional traction line is connected with the two bottom legs of the middle support into a whole through a triangular rope; the triangular rope is made of a section of brake cable, the middle part of the triangular rope and the bottom end of another traction cable (namely, an inner rope arranged in a pipe skin of the brake cable) are tied and connected into a whole, and then the two ends of the triangular rope are respectively inserted into through holes on two bottom legs of the middle support, so that a three-point structure (so called triangular rope) is formed; the penetrated triangular rope can be flexibly drawn back and forth in the through hole; the reserved length (namely the movable forming) of the triangular rope is determined according to the vertical to horizontal movable stroke of the middle support, the two ends of the triangular rope are tensioned when the middle support is in a horizontal state, the rope in an additional traction line is pulled outwards to extend out for a section, and the length of the extended section is just the stroke length (the shared rear wheel brake handle is in a non-braking state) which can drive the support to incline downwards to cause the two caster wheels to be grounded when the rear wheel is operated to brake; then, two ends of the triangular rope are sealed by seal heads (line hammers) so as to ensure that the middle support is not influenced by another traction line when in a supporting state; thus, an additional traction wire and a middle support linkage structure are arranged;

the action process of the newly added structure is as follows: when the emergency brake of the rear wheel is carried out during the running of the vehicle, the shared rear wheel brake handle drives the traction arm (rocker arm) to rotate for an angle, the rotation of the traction arm pulls out a cord in an additionally arranged traction line for a certain distance, the other end (lower end) of the cord is pulled by the triangular cord to support downwards to rotate and form inclination (namely the middle support is inclined downwards from a flat state), the two casters are synchronously grounded due to the downward inclination of the middle support, and the two grounded casters play a role in supporting the balance of the vehicle body during the emergency brake;

when the brake of the rear wheel is released, the shared rear wheel brake handle is loosened, the inclined middle support is reset to the original flat state under the action of the tension of the spring of the middle support, and the shared rear wheel brake handle is used for finishing the protection action process during one emergency brake of the rear wheel;

when the middle support needs to be supported during parking, the triangular rope can flexibly slide in the through hole, and the triangular rope is in a tensioning state only when the middle support is in a flat state, so that the normal parking support using of the middle support is not influenced; this is the use of the present application;

the beneficial technological effect of this application is: the rear wheel brake handle used on the vehicle is fully utilized, the characteristic of a linkage structure is formed by an additional traction wire and the middle support, two trundles in the middle support are driven to be synchronously grounded during emergency braking of the rear wheel, the synchronous action of emergency braking of the rear wheel of the electric vehicle and grounding of the trundles in the middle support is realized, and the unstable phenomenon of left and right swinging of the vehicle body caused by transverse slipping of the rear wheel during emergency braking is fundamentally eliminated by the characteristic of the linkage structure; through the technical improvement of the electric vehicle in the prior art, the novel structural characteristics and the novel function of the electric vehicle are increased, so that the structural characteristics and the service performance of the electric vehicle are more perfect.

Drawings

In the drawings:

FIG. 1 is a front view of a fall arrest device modified from a mid-support;

FIG. 2 is a front view of the modified mid-support;

fig. 3 is a front view of the modified rear wheel brake handle.

Description of reference numerals:

in the figure, 1, a middle support; 2. a rear wheel brake handle is shared; 3. a pull wire; 4. a fixed mount; 5. a rear wheel brake handle is used; 6. a traction arm; 7. a clamping groove; 8. a caster wheel; 9. another drum head positioning plate; 10. a drum head; 11. sealing the end; 12. a triangular rope; 13. a bottom leg; 14. a caster frame; 15. a damper; 16. a through hole; 17. a thread rope.

Detailed Description

As shown in fig. 1, 2 and 3, a fall-down prevention device modified from a middle support 1 is provided, so that the accident potential of easy fall-down caused by sudden braking of a two-wheeled electric vehicle and a motorcycle in the prior art is eliminated;

the structure of the device is formed by matching and connecting a shared rear wheel brake handle 2, an additional traction wire 3, a newly-added traction wire fixing frame 4 and a modified middle support 1;

the shared rear wheel brake handle 2 is formed by modifying a used rear wheel brake handle 5 (the shared rear wheel brake handle is called as a shared brake handle because the rear wheel brake handle has two functions), and the technical means adopted for modifying the shared rear wheel brake handle 2 is as follows: a section of traction arm (namely a rocker arm) 6 is connected to the outer side of the rear wheel brake handle 5, the traction arm 6 is made of steel plates, the traction arm 6 and the rear wheel brake handle 5 made of steel are welded and connected into a whole, and the welded traction arm 6 and the rear wheel brake handle 5 are on the same plane; the outer end (one side close to the handlebar is inner) of the traction arm 6 is provided with a clamping groove 7 connected with the end of a cord 17 of a brake cable, and the structure of the clamping groove 7 (note: the structure of the clamping groove is the clamping groove structure in the prior art) is used for connecting the traction arm 6 with one end of a joint of the cord 17 in another traction cable 3; the length of the traction arm (namely the rocker arm) 6 can meet the requirement that two caster wheels 8 in the support 1 land during traction when the rear wheel emergency brake is operated (when the brake handle is pinched), so that the swinging phenomenon of the hip of the vehicle body caused by the emergency brake of the rear wheel of the electric vehicle is overcome;

another drum head positioning plate 9 is connected to the drum head positioning plate for fixing one end of the drum head of the rear wheel brake cable, and the other drum head positioning plate 9 is formed by cutting (removing the annular sleeve part fixed on the handlebar, and increasing the length if not enough) the drum head positioning plate; the other section of drum head positioning plate 9 is connected with the existing drum head positioning plate for fixing one end of the rear wheel brake line drum head into a whole by welding; the length of the other section of drum head positioning plate 9 after welding is matched with the length of the traction arm (rocker arm) 6, and the other section of drum head positioning plate 9 is used for fixing a drum head 10 at one end of another traction wire 3; thus, the remanufacturing feature of the brake lever on the handlebar is formed (i.e., the remanufacturing feature on the handlebar is finished);

the common rear wheel brake handle 2 modified by the method is added with the structural characteristics and the function of synchronous linkage with the middle support 1; therefore, when the rear wheel emergency brake is adopted, the two trundles 8 at the lower end of the middle support 1 can be synchronously driven to land, and the two landed trundles 8 at the lower end of the middle support 1 have the function of assisting balance for the swinging phenomenon of the hip turn caused by the rear wheel brake, so that the unstable phenomenon of the left-right swinging of the vehicle body caused by the rear wheel emergency brake can be eliminated when the rear wheel is subjected to emergency brake;

the following is to reform transform the automobile body of electric motor car, and the part of reforming transform is: a drum head positioning plate, namely a fixing frame 4, is additionally arranged below a bottom beam of the electric vehicle, the fixing frame 4 is formed by modifying a lower fixing positioning plate in a rear wheel brake in the prior art, a plate body of the modified fixing frame 4 is made into a right-angled trapezoid, and the fixing frame 4 and a middle girder of a vehicle body are vertically welded and connected into a whole; the fixed frame 4 is used for installing and fixing the lower end of another traction wire 3; thus, the related remanufacturing characteristics of the body of the electric vehicle are formed (finished);

the following is to install another traction line 3: another traction line 3 is a brake line (both front and rear brake lines can be used after being modified and can be long enough) matched with the vehicle, the traction line 3 is laid on the vehicle body along a section of path of the rear wheel brake line, and drum heads (the drum heads at two ends are different in shape) of outer leather tubes at two ends of the traction line 3 are respectively connected with another drum head positioning plate 9 and the fixing frame 4 into a whole; two ends of a cord 17 in the outer skin tube of the traction wire 3 are respectively fixedly connected with the clamping groove 7 in the traction arm 6 and the middle part of the triangular rope 12 into a whole; in this way, a modified feature of an additional traction wire 3 is formed; namely the installation process of the other traction wire 3 is finished;

the following is a modification of the centering support 1: two changes are provided, one is that for the modification of the bottom end of the middle support 1, the bottom parts of two bottom legs 13 of the middle support 1 are respectively cut off (only one caster is shown in the figure for comparison), the casters 8 are respectively arranged under the cut-off end surfaces, and the caster frame 14 of the caster 8 and the bottom parts of the two bottom legs 13 of the middle support 1 are respectively welded and connected into a whole; the length of the two bottom legs 13 of the middle support 1 after welding the caster 8 is equal to the length of the bottom legs before truncation; thus ensuring the original use function of the middle support 1 to be unchanged;

the casters 8 are respectively arranged below the two bottom legs 13 of the middle support 1, the casters with a wheel shaft type structure are selected (namely the casters with wheels and shafts fixed into a whole, and the wheel shafts of the casters can integrally rotate in the shaft holes of the caster frames), the inner sides of the two caster frames 14 are respectively provided with a damper 15, one end of the wheel shaft of each caster 8 is inserted into the shaft hole of the damper 15 and then connected into a whole, and the shell of each damper 15 and the caster frame 14 are fixedly connected into a whole; so that the caster 8 and the damper 15 are installed and connected into a whole; the mounted damper 15 is used for controlling the flexible rotation of the caster 8 and making resistance for the rotation of the caster 8; therefore, the phenomenon that the caster 8 slides due to uneven terrain when the middle support 1 supports the vehicle body and parks is prevented; when the caster 8 is braked and lands, the friction resistance with the ground is generated, and the caster 8 helps to improve the braking effect of the brake while maintaining the balance of the vehicle body when braking; therefore, the damper 15 on the caster has double functions of parking and braking the electric vehicle;

secondly, two bottom legs 13 of the middle support 1 are modified: the adopted technical means is as follows: a through hole 16 is symmetrically drilled on each of the two bottom legs 13 of the middle support 1, and the through hole 16 is positioned above the middle position of the length of each bottom leg 13; the through hole 16 is used for penetrating the triangular rope 12 and realizing connection with a rope 17 of another traction line 3; thus, the structural characteristics of the caster 8, the damper 15 and the through hole 16 are newly added in the modified middle support 1, and the modification of the middle support 1 is completed;

the following is the connection of another traction wire 3 with the middle support 1: the adopted technical means is as follows: an additional traction line 3 is connected with two bottom legs 13 of the middle support 1 into a whole through a triangular rope 12; the triangular rope 12 is made of a cord 17 of a section of brake cable, the middle part of the triangular rope 12 and the bottom end of the cord 17 (namely, an inner cord arranged in a tube skin of the brake cable) in another traction line 3 are tied and connected into a whole, and then the two ends of the triangular rope 12 are respectively inserted into through holes 16 on two bottom legs 13 of the middle support 1, so that a three-point structure (so called triangular rope) is formed; the penetrated triangular rope 12 can be flexibly drawn back and forth in the through hole 16; the reserved length (namely the movable forming) of the triangular rope 12 is determined according to the movable stroke of the middle support 1 from the vertical position to the horizontal position, the two ends of the triangular rope 12 are tensioned when the middle support 1 is in the horizontal position, the rope 17 of the other traction line 3 is pulled outwards to extend out for a section, and the length of the extended section is just the stroke length which can drive the middle support 1 to incline downwards to cause the two caster wheels 8 to be grounded when the rear wheel brake is operated; then, two ends of the triangular rope 12 are sealed by a seal head (a plumb bob) 11, so that the middle support 1 is not influenced by another traction wire 3 when being supported; thus, an additional traction wire 3 and a linkage structure of the middle support 1 are arranged;

the action process of the newly added structure is as follows: when the emergency brake of the rear wheel is carried out during the running of the vehicle, the shared rear wheel brake handle 2 drives the traction arm (rocker arm) 6 to rotate for an angle, the rotation of the traction arm (rocker arm) 6 pulls out a cord 17 in an additionally arranged traction line 3 for a certain distance, the other end (lower end) of the cord 17 is pulled by the triangular rope 12 to pull the middle support 1 to rotate downwards to form an inclination, the downward inclination of the middle support 1 enables the two caster wheels 8 to be synchronously grounded, and the two grounded caster wheels 8 play a role in supporting the balance during the emergency brake of the vehicle body;

when the brake of the rear wheel is released, the shared rear wheel brake handle 2 is loosened, the inclined middle support 1 is reset to the original flat state under the action of the tension of the spring of the middle support, and the shared rear wheel brake handle 2 finishes the protection action process during one emergency brake of the rear wheel;

when the middle support 1 needs to be supported during parking, the triangular rope 12 can flexibly slide in the through hole 16, and the triangular rope 12 is in a tensioned state only when the middle support 1 is in a flat state, so that the normal parking supporting use of the middle support 1 is not influenced; this is the use of the present application;

the beneficial technological effect of this application is: the rear wheel brake handle 5 used on the vehicle is fully utilized, the characteristic of a linkage structure is formed by the additionally arranged traction wire 3 and the middle support 1, two trundles 8 in the middle support 1 are driven to be synchronously grounded during emergency braking of the rear wheel, the synchronous action of emergency braking of the rear wheel of the electric vehicle and grounding of the trundles 8 in the middle support 1 is realized, and the instability phenomenon of the vehicle body swinging left and right caused by transverse slipping of the rear wheel during emergency braking is fundamentally eliminated by the characteristic of the linkage structure; through the technical improvement of the electric vehicle in the prior art, the novel structural characteristics and the novel function of the electric vehicle are increased, so that the structural characteristics and the service performance of the electric vehicle are more perfect.

Claims

1. A fall-down prevention device reformed from a middle support is used for eliminating the accident potential caused by the sudden braking of a two-wheeled electric vehicle and a motorcycle in the prior art, wherein the accident potential is easy to fall down; the method is characterized in that:

the structure of the device is formed by matching and connecting a shared rear wheel brake handle (2), an additionally arranged traction line (3), a newly added traction line fixing frame (4) and a modified middle support (1);

the shared rear wheel brake handle (2) is formed by modifying an existing rear wheel brake handle (5), and the technical means adopted for modifying the shared rear wheel brake handle (2) is as follows: a section of traction arm (6) is connected to the outer side of the rear wheel brake handle (5), the traction arm (6) is made of steel plates, the traction arm (6) and the rear wheel brake handle (5) made of steel are welded and connected into a whole, and the welded traction arm (6) and the rear wheel brake handle (5) are on the same plane; the outer end of the traction arm (6) is provided with a clamping groove (7) connected with the end of a cord (17) of a brake cable, and the clamping groove (7) is structurally used for connecting the traction arm (6) with one end of a joint in the cord (17) of another traction cable (3); the length of the towing arm (6) can meet the requirement that two caster wheels (8) in the support (1) are grounded during towing when the rear wheel emergency brake is operated, so that the swinging phenomenon of the hip of a vehicle body caused by the emergency brake of the rear wheel of the electric vehicle is overcome;

another section of drum head positioning plate (9) is connected to the drum head positioning plate for fixing one end of the rear wheel brake cable drum head, and the other section of drum head positioning plate (9) is formed by cutting and modifying the drum head positioning plate; the other section of drum head positioning plate (9) is welded and connected with the existing drum head positioning plate for fixing one end of the rear wheel brake line drum head into a whole; the length of the other section of drum head positioning plate (9) after welding is matched with the length of the traction arm (6), and the other section of drum head positioning plate (9) is used for fixing one end drum head (10) of another traction wire (3) for use; thus, the remanufacturing characteristic of the brake handle on the handlebar is well realized;

the following is to reform transform the automobile body of electric motor car, and the part of reforming transform is: a drum head positioning plate, namely a fixing frame (4), is additionally arranged below a bottom beam of the electric vehicle, the fixing frame (4) is formed by modifying a lower fixing positioning plate in a rear wheel brake in the prior art, a plate body of the modified fixing frame (4) is made into a right-angled trapezoid, and the fixing frame (4) and a middle girder of a vehicle body are vertically welded and connected into a whole; the fixed frame (4) is used for installing and fixing the lower end of another traction wire (3); therefore, the related remanufacturing characteristics of the body of the electric vehicle are well made;

the following is a traction line (3) installed additionally: a traction wire (3) is additionally arranged and is a brake wire matched with the vehicle for use, the traction wire (3) is laid on the vehicle body along a section of path of the rear wheel brake wire, and the drum heads of the outer leather tubes at the two ends of the traction wire (3) are respectively connected with the other drum head positioning plate (9) and the fixing frame (4) into a whole; two ends of a cord (17) in the outer skin tube of the traction wire (3) are respectively fixedly connected with the clamping groove (7) in the traction arm (6) and the middle part of the triangular rope (12) into a whole; thus, the remanufacturing and installation process of an additional traction wire (3) is completed;

the following is a modification of the centering support (1): the bottom end of the middle support (1) is modified, the bottoms of two bottom legs (13) of the middle support (1) are respectively cut off, the caster wheels (8) are respectively arranged below the cut-off end surfaces, and the caster frames (14) of the caster wheels (8) and the bottoms of the two bottom legs (13) of the middle support (1) are respectively welded and connected into a whole; the length of the two bottom legs (13) of the middle support (1) after the caster (8) is welded is equal to the length of the bottom legs before the caster is cut off; thus ensuring the original use function of the middle support (1) to be unchanged;

the casters (8) are respectively arranged below the two bottom legs (13) of the middle support (1), the casters are selected to be in a wheel shaft type structure, the inner sides of the two caster frames (14) are respectively provided with a damper (15), one end of a wheel shaft of each caster (8) is inserted into a shaft hole of the damper (15) and then connected into a whole, and the shell of each damper (15) and the corresponding caster frame (14) are fixedly connected into a whole; so that the caster wheel (8) and the damper (15) are installed and connected into a whole; the mounted damper (15) is used for controlling the flexible rotation of the caster (8) and making resistance for the rotation of the caster (8); therefore, the phenomenon that the caster (8) slides due to uneven terrain when the middle support (1) supports the vehicle body to park is prevented; when the caster wheel (8) is braked and landed, the friction resistance with the ground is generated, and the caster wheel (8) helps to improve the braking effect of the brake while maintaining the balance of the vehicle body when the brake is performed;

secondly, two bottom legs (13) of the middle support (1) are reformed: the adopted technical means is as follows: two bottom legs (13) of the middle support (1) are symmetrically drilled with a through hole (16), and the through hole (16) is positioned above the middle position of the length of the bottom legs (13); the through hole (16) is used for penetrating the triangular rope (12) and realizing connection with a rope (17) of another traction line (3); therefore, the structural characteristics of the caster (8), the damper (15) and the through hole (16) are newly added in the modified middle support 91, and the modification of the middle support (1) is completed;

the following is the connection of another traction line (3) with the middle support (1): the adopted technical means is as follows: an additional traction line (3) is connected with the two bottom legs (13) of the middle support (1) into a whole through a triangular rope (12); the triangular rope (12) is made of a cord (17) of a section of brake cable, the middle part of the triangular rope (12) and the bottom end of the cord (17) in another traction line (3) are tied and connected into a whole, and then the two ends of the triangular rope (12) are respectively inserted into through holes (16) on two bottom legs (13) of the middle support (1), so that a three-point structure is formed; the penetrated triangular rope (12) can be flexibly drawn back and forth in the through hole (16); the reserved length of the triangular rope (12) is determined according to the moving stroke of the middle support (1) from vertical to horizontal, when the middle support (1) is in a horizontal state, two ends of the triangular rope (12) are tensioned, at the moment, a rope (17) of an additional traction line (3) is pulled outwards to extend out for a section, and the length of the extended section is just the stroke length which can drive the middle support (1) to incline downwards to enable two trundles (8) to be grounded when a rear wheel brake is operated; then, two ends of the triangular rope (12) are sealed by using end sockets (11), so that the middle support (1) is not influenced by another traction wire (3) when in a supporting state; thus, an additional traction wire 93 and the linkage structure of the middle support (1) are arranged;

the action process of the newly added structure is as follows: when the emergency brake of the rear wheel is carried out during the running of the vehicle, the common rear wheel brake handle (2) drives the traction arm (6) to rotate for an angle, the rotation of the traction arm (6) pulls out a cord (17) in an additionally arranged traction line (3) for a certain distance, the other end of the cord (17) pulls the middle support (1) through the triangular rope (12) to rotate downwards to form an inclination, the downward inclination of the middle support (1) enables the two casters (8) to be synchronously grounded, and the two grounded casters (8) play a role in supporting the balance of the vehicle during the emergency brake;

when the brake of the rear wheel is released, the shared rear wheel brake handle (2) is loosened, the inclined middle support (1) is reset to the original flat state under the action of the tension of the spring of the middle support, and the shared rear wheel brake handle (2) completes the protection action process during one emergency brake of the rear wheel;

when the middle support (1) needs to be supported during parking, the triangular rope (12) can flexibly slide in the through hole (16), and the triangular rope (12) is in a tensioning state only when the middle support (1) is in a flat state, so that the normal parking supporting use of the middle support (1) is not influenced.