CN209852395U - Wheel components and handcart - Google Patents

Abstract

The utility model relates to a roller component and a trolley, wherein the roller component comprises a positioning seat, a braking component and a roller which are sequentially arranged on a guide shaft, the end surface of a shaft ring of the braking component is a cam surface, and the end surface of the roller can be collided or loosened to extrude the end surface of the roller when rotating, so that a braking structure is formed; the trolley with the roller assembly comprises a front frame rod, a rear frame rod, a bottom frame, a grab rail and a flexible bag body; the bag body is made of flexible fabric, the bottom of the bag body is placed on the bottom frame, and at least two corresponding edges of the four edges of the opening are hung on the upper edges of the front frame rod and the rear frame rod; the roller components are arranged at two ends of a guide shaft at the lower part of the rear frame rod. The utility model provides a wheel components only needs three part cooperation, can be easy to assemble on the guide shaft, and has brake function, uses on especially being fit for all kinds of simple handcart.

Description

Wheel components and handcart

The technical field is as follows:

the utility model relates to a wheel components and handcart especially have brake function's gyro wheel to and use this wheel components's handcart, and this handcart adopts flexible surface fabric processing such as net cloth, oxford to form.

Background art:

the folding shopping cart has the advantages of being light and foldable, is popular with the public, and becomes a necessary tool for household shopping. CN201520690086.5 discloses a foldable shopping cart, which comprises a basket, a handrail and rollers; the bicycle basket comprises a front frame, a rear frame, a bottom frame and a connecting strip for connecting the front frame and the rear frame; the two ends of the handrail below the bottom frame are provided with connecting rods which support the front part of the bottom frame; the middle part of the handrail is hinged with a connecting strip to form angle positioning; the bottom frame below is provided with the backing sheet, and this backing sheet one side is articulated the setting with the connecting rod, and the opposite side is articulated the setting with the bottom frame connecting strip, also forms the relevance of handrail and bottom frame promptly to when folding, can pull handrail lower part, follow the preceding car frame and fold to back car frame one side. The folding shopping cart is also a typical representative of a plurality of shopping carts on the market at present, and due to the consideration of folding convenience, the front frame and the rear frame can only be related by connecting strips and cannot be made of materials with dense hole structures such as grids. The small or flat articles cannot be directly placed in the shopping cart, and the dragging vibration is easy to fall off, which is also the biggest defect of the shopping cart.

Therefore, CN201720162611.5 discloses a magnetic attraction type netted shopping cart, which comprises a shopping cart body, wherein the shopping cart body comprises a bottom plate, a front panel, a rear panel, a left panel and a right panel, one end of each of the left panel and the right panel is hinged to a corresponding vertical rod on two sides of the front panel, and the other end of each of the left panel and the right panel is a free end; the upper end of the vertical rod and the rear panel are provided with a cross rod between the corresponding rear vertical rods, the left panel and the right panel are both positioned between the two cross rods, and the free ends of the left panel and the right panel and the corresponding cross rods are fixed in a magnetic attraction mode. In this patent technique, bottom plate, front panel, rear panel, left side board, the design of the five sides of right panel adoption thinner netted board, can directly be used for holding little article, in order to solve folding problem, will control the panel and adopt single-ended articulated, and another is the method that the free end passes through magnetism to inhale, realize and correspond the fixed relation between the horizontal pole. The shopping cart is creative, but the use trouble is increased.

The use of wheels with braking function in the field of trolleys is relatively rare, while in the field of bags or prams, most have braking wheels, but most have complex wheel support mechanisms, such as chinese patent application No. 012330841, the disclosed trunk caster brake device, and patent application No. 201120556269X, the disclosed wheel assembly. It cannot be used on shopping trolleys either because of cost.

Therefore, provide simple and easy and take braking function's gyro wheel mechanism to supporting the scheme that uses on the handcart, it is to become the utility model discloses the direction of research.

The invention content is as follows:

the utility model aims at designing a roller component, wherein a roller is matched with a positioning seat through a convex ring of an end surface shaft sleeve to form a positioning and braking structure; another purpose is a trolley with the roller assembly, which can be folded to tighten the flexible bag body.

The utility model discloses technical scheme realizes like this:

a roller assembly, characterized in that: the roller positioning device comprises a roller, a positioning seat and a braking part, wherein a shaft sleeve is convexly arranged on the inner end surface of the roller along the direction of a shaft hole, the outer edge of the shaft sleeve is of a waisted structure, and a convex ring is formed at the end part of the shaft sleeve; the positioning seat is provided with a shaft seat and a suspension claw, the suspension claw is fixedly locked on a guide shaft penetrating through a roller shaft hole by the shaft seat, and the suspension claw is buckled at the convex ring and movably positions the roller; the braking piece is provided with a shaft ring and a pedal which are connected, the hole diameter of the shaft ring is equivalent to that of the shaft hole of the roller, and the end surface of the shaft ring is a cam surface; the braking piece is arranged between the positioning seat and the roller, the cam surface is abutted against the end face of the shaft seat, and the braking piece can be forced to move axially by rotation and abutted against or loosened from extrusion on the end face of the convex ring of the roller; the pedal is arranged on a tangent line of the shaft ring, and the shaft ring is driven to rotate by the pedal.

The suspended claws of the positioning seat and the convex ring of the roller have the same circumferential structure, and chamfer claw surfaces are formed on the inner edge of the outer end surface; the outer edge of the convex ring is formed into a chamfer ring surface, the chamfer ring surface and the chamfer claw surface form an assembly surface, and the chamfer ring surface of the convex ring is abutted against the chamfer claw surface of the suspension claw during roller assembly to force the suspension claw to open and slide in, so that a movable positioning structure is formed.

The surface of the shaft seat of the positioning seat, which is abutted to the cam surface of the braking part shaft ring, is an inclined surface, and the cam surface is matched with the inclined surface, so that the braking stroke can be shortened.

A handcart comprises a front frame rod, a rear frame rod, a bottom frame, a grab rail and the roller components; the roller assemblies are arranged on two sides of the lower part of the rear frame rod; the method is characterized in that:

the lower parts of the front frame rod and the rear frame rod are correspondingly hinged to the front edge and the rear edge of the bottom frame, and a connecting rod is respectively hinged between the upper parts of the two sides of the front frame rod and the upper part of the two sides of the rear frame rod to form the associated support of the front frame rod and the rear frame rod and build up two side vertical surfaces with foldable quadrangles;

the lower part of the grab rail is provided with a front cross bar, the handcart is opened in place, and the front cross bar is supported at the lower side of the bottom frame;

the grab rail inclines backwards, and the middle part of the grab rail is hinged at the middle rear part of the connecting rod;

the front end part of the associated rod is hinged at the lower end part of the grab rail, and the rear part of the associated rod is hinged at the side surface of the bottom frame, so that the action association when the grab rail is opened or folded is formed;

a bag body made of flexible fabric, the bottom of the bag body is arranged on the bottom frame, and four sides of the opening are at least two corresponding to each other

The side is hung on the upper edges of the front frame rod and the rear frame rod;

the lower part of the rear frame rod is fixedly locked with a guide shaft, the end parts of the two ends of the guide shaft, which extend out of the rear frame rod, are respectively provided with the roller assemblies, the positioning seat, the braking part and the roller are sequentially assembled from outside to inside, and the positioning seat is fixedly riveted on the guide shaft through a rivet.

The handrail rod is of a folding structure and comprises an upper U-shaped rod and a lower U-shaped rod, the end parts of the two U-shaped rods are hinged together, and a backward turning limiting mechanism is arranged; the middle section of the lower U-shaped rod forms a front cross rod, can be supported on the lower side of the bottom frame, and is provided with a front guide roller.

The backward turning limiting mechanism is a plastic hinge and comprises a left half leaf, a right half leaf and a rivet for riveting the left half leaf and the right half leaf together; the left half page and the right half page are in rotational symmetry structures and are provided with disc ends which are in contact with each other and rod sleeve ends which are positioned in the tangential direction of the discs, and the outer bottoms of the rod sleeves which are positioned at the disc ends in place are abutted to each other when the rods are opened to form backward turning limiting.

The positioning seat in the roller assembly is formed with an upward rod seat; the rear frame rod consists of an inverted U-shaped rod and a guide shaft, two ends of the inverted U-shaped rod are directly inserted into the rod seat and are riveted through rivets, and the positioning seat forms connection between the inverted U-shaped rod and the guide shaft to form the whole rear frame rod.

The front frame rod consists of a short U-shaped rod and two upright rods hinged at the end part of the short U-shaped rod, the upper end part of each upright rod is hinged with the front end part of the connecting rod, or the front end part of the connecting rod is hinged with the upper end part of each upright rod after being transited by a plastic piece; the lower end parts of the upright rod pieces are hinged on the supporting rods on two sides of the bottom frame; the bottom frame is of an H-shaped structure, and a steel wire or a steel wire mesh is connected between the supporting rods on the two sides.

The front frame rod, the rear frame rod and the grab rail are all inverted U-shaped rods formed by bending a rod piece; the bottom frame is of an H-shaped structure, supporting rods are arranged on two sides of the bottom frame, and steel wires or steel wire meshes are connected between the supporting rods; the bottom frame is hinged with the ends of the inverted U-shaped rods of the front frame rod and the rear frame rod by means of the support rods on the two sides; and a front guide roller is arranged at the lower end part of the grab rail.

The bag body becomes rectangle tubular structure, has two kinds of location structures, respectively as follows: firstly, cloth sleeves are processed on the four vertical edges of the bag body, and are sleeved on two parallel rod sections on the two sides of the front frame rod and the rear frame rod by virtue of the cloth sleeves, so that the bag body is opened by the front frame rod and the rear frame rod; and the bottom of the bag body is placed on the bottom frame, and at least two corresponding edges of the four sides of the opening are hung on the upper edges of the front frame rod and the rear frame rod.

The roller component provided by the utility model can be conveniently installed on the guide shaft only by matching three parts, has a braking function, and is particularly suitable for being used on various simple trolleys; the trolley matched with the trolley is combined with the flexible bag body through the folding frame, and the bag body does not influence the placement of small articles and can be folded along with the frame; the optimized folding handrail can be closely collected outside the frame, does not occupy space, and can also be in an unfolded state of the trolley, including that a load-bearing object is integrally placed in a car trunk, so that the application occasion of the trolley is expanded.

Description of the drawings:

the present invention will be further explained with reference to the following specific drawings:

FIG. 1 shows a schematic view of a roller assembly

FIG. 2 is an exploded view of the roller assembly

FIG. 3 shows a rear view of the scroll wheel assembly

FIG. 4 shows a schematic view of a cart support

FIG. 5 shows a hand truck armrest folded schematic

FIG. 6 is a side view of the folding process of the armrest of the cart

Fig. 7 shows a schematic view of the trolley in a collapsed state

FIG. 8 shows a side view of the cart in a collapsed position

FIG. 9 shows a schematic view of a plastic hinge

FIG. 10 is a schematic view showing the plastic hinge being turned upside down

FIG. 11 shows a schematic view of a cart

FIG. 12 shows a schematic view of a cart

FIG. 13 shows a schematic view of a cart two stand

FIG. 14 shows a two-leg folding view of the cart

Wherein

1-roller 11-shaft sleeve 12-convex ring 121-chamfer ring surface

2-positioning seat 21-axle seat 211-inclined plane 22-hanging claw

221-chamfer claw surface 23-rod seat 3-brake piece 31-shaft ring

311-cam surface 32-pedal 4-guide shaft 5-front frame rod

51-short U-shaped rod 52-upright rod 6-rear frame rod 61-inverted U-shaped rod

7-bottom frame 71-support rod 72-steel wire 8-handrail rod

81-upper U-shaped rod 82-lower U-shaped rod 821-front cross bar 822-front guide roller

83-plastic hinge 831-disc end 832-rod sleeve end 833-rod sleeve outer end part

834-cylindrical tenon 835-cylindrical mortise 84-connecting rod 85-associated rod

851 extension 86 plastic part 9 bag 91 cloth cover

The specific implementation mode is as follows:

referring to fig. 1, 2 and 3, the roller assembly includes a roller 1, a positioning seat 2 and a braking member 3. Wherein:

the inner end surface of the roller 1 is convexly provided with a shaft sleeve 11 along the shaft hole direction, the outer edge of the shaft sleeve 11 is of a waist-contracting structure, and a convex ring 12 is formed at the end part; the shaft hole can be a through hole or a blind hole. According to the design requirement of bearing capacity, a bearing or a copper sleeve can be added in the shaft hole to reduce the abrasion between the shaft hole and the guide shaft 4.

The positioning seat 2 is provided with a shaft seat 21 and a suspending claw 22, and is locked on the guide shaft 4 penetrating through the shaft hole of the roller by the shaft seat 21, and the suspending claw 22 is buckled at the convex ring 12 to movably position the roller 1. Furthermore, the suspension claws 22 of the positioning seat and the convex ring 12 of the roller have the same circumferential structure, and a chamfer claw surface 221 is formed on the inner edge of the outer end surface; correspondingly, the outer edge of the convex ring 12 is formed with a chamfered ring surface 121, the chamfered ring surface 121 and the chamfered claw surface 221 form an assembling surface, when the roller 1 is assembled, the chamfered ring surface 121 of the convex ring is abutted against the chamfered claw surface 221 of the suspension claw, so that the suspension claw 22 is forced to open and slide in, and the roller assembling process is simplified. In this embodiment, the shaft seat 21 of the positioning seat is an open structure, and may also be designed into a shaft ring form, and is sleeved on the guide shaft 4 and locked by a rivet.

The braking piece 3 is provided with a shaft ring 31 and a pedal 32 which are connected, the hole diameter of the shaft ring 31 is equivalent to the shaft hole of the roller 1, and the end surface of the shaft ring 31 is a cam surface 311; the braking part 3 is arranged between the positioning seat 2 and the roller 1, the cam surface 311 is abutted against the end surface of the shaft seat 21, the braking part 3 can be forced to move axially by rotating, and the braking part is abutted against or loosens the extrusion on the end surface of the roller convex ring 12 to realize braking or releasing action; the pedal 32 is disposed on a tangent of the collar 31, and the collar 31 is rotated by the pedal 32.

In order to shorten the braking stroke, the surface of the shaft seat 21 of the positioning seat, which is abutted against the cam surface 311 of the braking member shaft ring, is an inclined surface 211, and the cam surface 311 is matched with the inclined surface 211, so that the braking member can rotate by a smaller angle, and a larger axial movement stroke is obtained.

The first embodiment is as follows:

referring to fig. 4 to 11, this example is a foldable stroller suitable for use in a trunk of an automobile, and particularly, in a state of holding articles, the stroller is entirely put into the trunk after the grab bar is folded. The structure is characterized as follows:

a handcart comprising the above roller components also comprises a front frame rod 5, a rear frame rod 6, a bottom frame 7, a grab bar 8, a bag body 9 made of flexible fabric, a connecting rod 84 for connecting the upper parts of the two sides of the front and rear frame rods 5 and 6 and a connecting rod 85 for connecting the lower end part of the grab bar 8 and the side surface of the bottom frame 7; the front frame rod 5, the rear frame rod 6 and the grab rail 8 are rectangular frames or three-side frames which are formed by enclosing rod pieces; the bottom frame 7 is of an H-shaped structure, supporting rods 71 are arranged on two sides of the bottom frame, steel wires 72 or steel wire meshes are connected between the supporting rods 71, and the bottom of the bag body 9 is supported densely enough; the bag body 9 is made of flexible fabric, the bottom of the bag body is placed on the bottom frame 4, two sides corresponding to four sides of the opening are hung on the upper edges of the front frame rod 5 and the rear frame rod 6, and the bag body can be opened and folded along with the opening.

More specifically, the front frame rod 5 is composed of a short U-shaped rod 51 and two upright rods 52 hinged at the end of the short U-shaped rod, the upper end of the upright rod 52 is hinged with the front end of the connecting rod 84, or the front end of the connecting rod 84 is excessive through a plastic piece 86 and then is hinged with the upper end of the upright rod 52, so that the problem that the upright rod 52 cannot be close to the hinge due to the bending of the short U-shaped rod 51 is solved, the upright rod 52 is flush with the connecting rod 84 and does not occupy excessive height space, and the plastic piece 86 is wrapped at the ends of the direct rod 52 and the connecting rod 84, so that the protection effect is achieved, and the end part can be prevented from hurting people or bags; the lower end of the upright member 52 is hinged on the support bar 71 at both sides of the bottom frame.

The rear frame rod 6 is a rectangular frame consisting of an inverted U-shaped rod 61 and a guide shaft 4, and the positioning seat 2 in the roller assembly is formed with an upward rod seat 23; the two ends of the inverted U-shaped rod 61 are directly inserted into the rod seat 23 and are riveted by rivets, and the positioning seat 2 forms the connection between the inverted U-shaped rod 61 and the guide shaft 4 to form the whole rear frame rod 6. During assembly, the frame rod 6 can be assembled firstly and then the braking piece 3 and the roller 1 are installed, or the roller 1 and the like can be installed at two ends of the guide shaft 4 firstly and then are riveted with the inverted U-shaped rod 61 finally, so that the assembly is more convenient.

The lower parts of the front and the rear frame rods 5 and 6 are correspondingly hinged at the front and the rear edges of the bottom frame 7, namely the front and the rear end parts of the supporting rod 71; a connecting rod 84 is respectively hinged between the upper parts of the two sides of the front and the rear frame rods 5 and 6 to form the associated support of the front and the rear frame rods 5 and 6, the support of the two side surfaces is formed by opening, namely, the quadrangular foldable two side vertical surfaces are built, and the traction function can be realized when the folding is carried out.

The grab bar 8, in this example, the grab bar is a folding structure, and comprises an upper U-shaped bar 81 and a lower U-shaped bar 82, the end parts of the two U-shaped bars are hinged together, and a backward turning limiting mechanism is arranged, if the backward turning angle can not exceed 250 degrees; a front rail 821 is formed by the middle section of the lower U-shaped bar 82, the trolley is opened in place, the front rail 821 is supported on the lower side of the bottom frame 7 to form a front support, for this purpose, a front guide roller 822 is arranged on the front rail 821, the front guide roller 822 is a universal wheel, the turning operation is convenient, and the trolley is supported by four wheels. For two-wheeled hand trucks, the foot pads are only locked to the front cross bar 821 to achieve a balanced ground support with the rollers 1.

The grab bar 8 inclines backwards, and the middle part is hinged at the middle rear part of the connecting rod 84 to form a connection with the upper part of the side vertical surface; the lower end part of the grab rail 8 is connected with the lower part of the side vertical surface through a connecting rod 85, the front end part of the connecting rod 85 is hinged on the lower end part of the grab rail 8, the rear part of the connecting rod 85 is hinged on the supporting rod 71 on the side surface of the bottom frame, the action connection when the grab rail 8 is opened or folded is formed, and the strengthening effect is also formed on the two side vertical surfaces.

In addition, when the handcart is pushed, the hand rail 8 can be slightly pressed down, so that the front end of the handcart is tilted by taking the roller 1 as a supporting point, the handcart can walk on the ground by virtue of the two rollers, the vibration caused by uneven ground is reduced, the handcart can be automatically adjusted to the optimal pushing force angle according to different people, and the handcart is only provided with a use method of the two rollers on the rear vertical surface.

Referring to fig. 9 and 10, the backward turning limiting mechanism in this embodiment is a plastic hinge 83, which includes a left half leaf, a right half leaf and a rivet for riveting the two together; the left half page and the right half page are in a rotational symmetry structure and are provided with a disc end 831 and a rod sleeve end 832 positioned in the tangential direction of the disc, and the outer bottom 833 of the rod sleeve positioned at the disc end is abutted when the left half page and the right half page are opened in place to form backward turning limit. Certainly, the left and right half pages of the plastic hinge 83 can also be formed into an asymmetric structure through two sets of dies, and besides forming a rivet hole, a cylindrical tenon 834 and a cylindrical mortise 835 structure which are tightly matched are formed on the adjacent surfaces of the disc end 831, so that the damping effect is achieved, the U-shaped rod 81 can be positioned to any angle, and the pre-positioning is convenient during assembly; in this illustration, the left and right half pages are asymmetric.

Referring to fig. 11, the bag body 9 is made of a flexible fabric, such as oxford fabric, mesh fabric, waterproof fabric, etc., and is flexible without hindering the folding of the support; the bottom of the bag body 9 is placed on the bottom frame 7, at least two corresponding sides of the four sides of the opening are hung on the upper edges of the front frame rod 5 and the rear frame rod 6, namely the middle sections of the short U-shaped rod 51 and the inverted U-shaped rod 61, in the figure, the other two corresponding sides are hung on the two connecting rods 84 to form balanced support of the four sides of the bag opening, and the bag body 9 is smoother. In order to achieve that the bottom of the bag body 9 can be organically connected with the bottom frame 7, the bag body can be tied and fixed on the support rods 71 at the two sides by using woven belts; in addition, a backward extending section 851 is arranged at the hinged point of the related rod 85 and the supporting rod 71, two sides of the bag body 9 are fastened on the end part of the extending section 851, when the support is opened or folded, the rear corner parts at two sides of the bag body 9 are synchronously pulled by the aid of the related rod extending section 851, the operation is more smooth, and the forming effect of the bag body after the bag body is opened is better.

Example two:

referring to figures 12, 13 and 14, this is an example of an alternative configuration of a trolley, also a conventional shopping cart, suitable for casual shopping. The structure is mainly and technically characterized in that the bag body 9 is made of flexible fabric, the support is improved, and the roller components with the braking function, namely the rollers 1 on the two sides of the rear frame rod 6, are arranged, so that the braking is needed when the structure is used conveniently.

In the shopping cart in the figure, because the restriction of space is not required to be considered, the front frame rod 5, the rear frame rod 6 and the grab bar 8 are all inverted U-shaped rods formed by bending a rod piece; the bottom frame 7 is of an H-shaped structure, supporting rods 71 are arranged on two sides of the bottom frame, and steel wires 72 or steel wire meshes are connected between the supporting rods; the bottom frame 7 is hinged with the two ends of the front frame rod 5 and the rear frame rod 6 of the inverted U-shaped rod by the support rods 71 at the two sides; a front cross bar 821 is arranged between the lower parts of the grab bars 8 of the inverted U-shaped bars, the handcart is opened in place and supported at the lower side of the bottom frame 7 by the front cross bar 821, and a front guide roller 822 is directly arranged at the lower end part of the grab bar 8; the lead roller 822 may also be mounted on the front rail 821. For a trolley with a smaller area of the bottom frame 7, the leading roller 822 is installed at the lower end of the grab bar 8, so that more stable support can be obtained. And the rollers 1 on the two sides of the rear frame rod 6 are positioned and supported by the two ends of the guide shaft 4 locked on the lower part of the rear frame rod 6, and the rollers 1 are positioned on the outer side of the rear frame rod 6, so that the pushing is more stable.

The bag body 9 is of a rectangular tubular structure, cloth sleeves 91 are processed on the four vertical edges of the bag body 9, the cloth sleeves 91 are sleeved on the two parallel rod sections at the two sides of the front and rear frame rods 5 and 6, and the bag body is expanded by the front and rear frame rods 5 and 6; in addition, the opening of the bag body 9 is hung on the upper edges of the front and rear frame rods 5 and 6 corresponding to two sides, or the four edges of the opening of the bag body 9 are hung on the upper edges of the front and rear frame rods 5 and 6 and the two connecting rods 84 corresponding to the four edges.

Claims (10)

1. A roller assembly, characterized in that: the roller positioning device comprises a roller, a positioning seat and a braking part, wherein a shaft sleeve is convexly arranged on the inner end surface of the roller along the direction of a shaft hole, the outer edge of the shaft sleeve is of a waisted structure, and a convex ring is formed at the end part of the shaft sleeve; the positioning seat is provided with a shaft seat and a suspension claw, the suspension claw is fixedly locked on a guide shaft penetrating through a roller shaft hole by the shaft seat, and the suspension claw is buckled at the convex ring and movably positions the roller; the braking piece is provided with a shaft ring and a pedal which are connected, the hole diameter of the shaft ring is equivalent to that of the shaft hole of the roller, and the end surface of the shaft ring is a cam surface; the braking piece is arranged between the positioning seat and the roller, the cam surface is abutted against the end face of the shaft seat, and the braking piece can be forced to move axially by rotation and abutted against or loosened from extrusion on the end face of the convex ring of the roller; the pedal is arranged on a tangent line of the shaft ring, and the shaft ring is driven to rotate by the pedal.

2. The roller assembly of claim 1, wherein: the suspended claws of the positioning seat and the convex ring of the roller have the same circumferential structure, and chamfer claw surfaces are formed on the inner edge of the outer end surface; the outer edge of the convex ring is formed into a chamfer ring surface, the chamfer ring surface and the chamfer claw surface form an assembly surface, and the chamfer ring surface of the convex ring is abutted against the chamfer claw surface of the suspension claw during roller assembly to force the suspension claw to open and slide in, so that a movable positioning structure is formed.

3. A roller assembly according to claim 1 or 2, wherein: the surface of the shaft seat of the positioning seat, which is abutted to the cam surface of the braking part shaft ring, is an inclined surface, and the cam surface is matched with the inclined surface, so that the braking stroke can be shortened.

4. A hand truck comprising a front frame bar, a rear frame bar, a bottom frame, a grab bar and the roller assembly of any one of the preceding claims 1 to 3; the roller assemblies are arranged on two sides of the lower part of the rear frame rod; the method is characterized in that: the lower parts of the front frame rod and the rear frame rod are correspondingly hinged to the front edge and the rear edge of the bottom frame, and a connecting rod is respectively hinged between the upper parts of the two sides of the front frame rod and the upper part of the two sides of the rear frame rod to form the associated support of the front frame rod and the rear frame rod and build up two side vertical surfaces with foldable quadrangles;

the lower part of the grab rail is provided with a front cross bar, the handcart is opened in place, and the front cross bar is supported at the lower side of the bottom frame;

the grab rail inclines backwards, and the middle part of the grab rail is hinged at the middle rear part of the connecting rod;

the front end part of the associated rod is hinged at the lower end part of the grab rail, and the rear part of the associated rod is hinged at the side surface of the bottom frame, so that the action association when the grab rail is opened or folded is formed;

the bag body is made of flexible fabric, the bottom of the bag body is placed on the bottom frame, and at least two corresponding edges of the four edges of the opening are hung on the upper edges of the front frame rod and the rear frame rod;

the lower part of the rear frame rod is fixedly locked with a guide shaft, the end parts of the two ends of the guide shaft, which extend out of the rear frame rod, are respectively provided with the roller assemblies, the positioning seat, the braking part and the roller are sequentially assembled from outside to inside, and the positioning seat is fixedly riveted on the guide shaft through a rivet.

5. A trolley according to claim 4, characterized in that: the handrail rod is of a folding structure and comprises an upper U-shaped rod and a lower U-shaped rod, the end parts of the two U-shaped rods are hinged together, and a backward turning limiting mechanism is arranged; the middle section of the lower U-shaped rod forms a front cross rod, can be supported on the lower side of the bottom frame, and is provided with a front guide roller.

6. A trolley according to claim 5, characterized in that: the backward turning limiting mechanism is a plastic hinge which comprises a left half leaf, a right half leaf and a rivet for riveting the left half leaf and the right half leaf together; the left half page and the right half page are in rotational symmetry structures and are provided with disc ends which are in contact with each other and rod sleeve ends which are positioned in the tangential direction of the discs, and the outer bottoms of the rod sleeves which are positioned at the disc ends in place are abutted to each other when the rods are opened to form backward turning limiting.

7. A trolley according to claim 4, characterized in that: the positioning seat in the roller component is formed with an upward rod seat; the rear frame rod consists of an inverted U-shaped rod and a guide shaft, two ends of the inverted U-shaped rod are directly inserted into the rod seat and are riveted through rivets, and the positioning seat forms connection between the inverted U-shaped rod and the guide shaft to form the whole rear frame rod.

8. A trolley according to claim 4, characterized in that: the front frame rod consists of a short U-shaped rod and two upright rods hinged at the end part of the short U-shaped rod, the upper end part of each upright rod is hinged with the front end part of the connecting rod, or the front end part of the connecting rod is hinged with the upper end part of each upright rod after being transited by a plastic piece; the lower end parts of the upright rod pieces are hinged on the supporting rods on two sides of the bottom frame; the bottom frame is of an H-shaped structure, and a steel wire or a steel wire mesh is connected between the supporting rods on the two sides.

9. A trolley according to claim 4, characterized in that: the front frame rod, the rear frame rod and the grab rail are all inverted U-shaped rods formed by bending a rod piece; the bottom frame is of an H-shaped structure, supporting rods are arranged on two sides of the bottom frame, and steel wires or steel wire meshes are connected between the supporting rods; the bottom frame is hinged with the ends of the inverted U-shaped rods of the front frame rod and the rear frame rod by means of the support rods on the two sides; and a front guide roller is arranged at the lower end part of the grab rail.

10. A trolley according to claim 4 or 9, characterized in that: the bag body becomes rectangle tubular structure, has two kinds of location structures, as follows respectively: firstly, cloth sleeves are processed on the four vertical edges of the bag body, and are sleeved on two parallel rod sections on the two sides of the front frame rod and the rear frame rod by virtue of the cloth sleeves, so that the bag body is opened by the front frame rod and the rear frame rod; and the bottom of the bag body is placed on the bottom frame, and at least two corresponding edges of the four sides of the opening are hung on the upper edges of the front frame rod and the rear frame rod.