Dolly for equal braking of multiple wheels

Abstract

The present invention relates to a dolly capable of uniform braking on a plurality of wheels. The dolly comprises at least one wheel coupled to both sides, a braking shaft connected to a tow bar rotatably coupled to a main body and reciprocating in accordance with rotation; and a braking bar rotatably coupled to the end of the braking shaft and angle-adjustable and in contact with the wheels located on both sides according to the wear condition of the wheels. With this configuration, the braking bar is angle-adjustably coupled to the braking shaft, and braking pads for braking the wheels are angle-adjustably coupled to each side of the braking bar. As the braking bar moves, the angle is adjusted according to the wear condition of the wheels and in contact simultaneously and evenly. Consequently, the braking force is adjusted according to the degree of wear of each wheel, thereby enabling stable braking performance through equal braking force on each wheel. Furthermore, excellent braking safety can be achieved by preventing slipping or drifting phenomena that may occur due to unbalanced braking.

Description

Technology Field

[0001] The present invention relates to a dolly capable of equal braking on a plurality of wheels, and more specifically, to a dolly capable of equal braking on a plurality of wheels used to transport heavy loads. Background Technology

[0003] Dollies are generally used in environments requiring the efficient management and transportation of large volumes of goods, such as logistics centers, or as devices to quickly and safely transport numerous air cargoes at airports.

[0004] These dollies maximize efficiency at work sites and can safely transport heavy loads that are difficult to move manually. They feature a sturdy main body designed to stably support loads of various shapes and sizes. Wheels are essentially mounted on the underside of the main body to facilitate movement, and typically, multiple wheels are balanced to distribute the weight of the load and enable smooth motion. A tow bar is installed at the front of the dolly to allow it to be towed by connecting it to another towing device, while a connection point is provided at the rear to connect another dolly or other devices if necessary.

[0005] In conventional dollies, the tow bar functions not only for towing but also operates in conjunction with a braking unit that controls the wheel's movement. When an operator lifts the tow bar upward relative to the main body and rotates it, the braking unit engages to stop the wheel's rotation and secure the dolly in place. Conversely, rotating the tow bar back to a horizontal position relative to the main body releases the brake, allowing the dolly to be moved freely. This method enables the dolly to be easily stopped and moved at the work site.

[0006] However, in work environments such as logistics centers or airports, dollies continuously transport heavy loads, which places significant stress on the wheels and eventually leads to wheel wear or uneven wear. When wheel wear occurs, the wheel's grip decreases, resulting in problems such as longer braking distances or weaker braking power.

[0007] A more serious issue is when uneven wear occurs on the wheels, which results in a dangerous situation where the contact surface between the wheel and the ground becomes uneven, causing the vehicle to pull to one side or fail to exert proper braking force during braking.

[0008] Meanwhile, the connection point located at the rear of the existing dolly also presents various inconveniences and problems. There is a risk of accidents caused by the connection suddenly separating due to unexpected external impacts during operation, and the process of connecting other dollies is complex and cumbersome, leading to delays in work time or increased worker fatigue. Prior art literature

[0010] Korean Intellectual Property Office Registration No. 10-2055288 (Dec. 6, 2019) Korean Intellectual Property Office Registration No. 20-0320125 (July 3, 2003) Korean Intellectual Property Office Registration No. 10-1919117 (November 9, 2018) Korean Intellectual Property Office Registration No. 20-0408824 (February 8, 2006) The problem to be solved

[0011] The present invention was devised to solve the aforementioned problems, and its purpose is not only to stably brake a dolly under a heavy load, but also to brake the wheel through uniform traction even when wear occurs on the wheel.

[0012] In particular, its purpose is to ensure uniform contact and transmit uniform braking force to multiple wheels even if uneven wear occurs on multiple wheels.

[0013] In addition, the purpose is to provide a connection part that does not easily separate or detach due to external impact and allows for quick connection and disconnection. means of solving the problem

[0015] To achieve the above objectives, a dolly capable of uniformly braking a plurality of wheels according to a preferred embodiment of the present invention comprises: a braking shaft connected to a tow bar rotatably coupled to a main body and reciprocating in accordance with rotation; and a braking bar rotatably coupled to the end of the braking shaft and having its angle adjusted and contacted according to the wear condition of the wheels located on both sides.

[0016] In addition, braking pads are coupled to both sides of the braking bar so as to be rotatable in a position facing the wheel, and are characterized by being angle-adjustable and in close contact according to the wear condition of the adjacent wheel.

[0017] In addition, the braking pad is characterized by being rotatably coupled by a pivot axis at a position facing the center of the adjacent wheel.

[0018] In addition, the brake pad is characterized by having a pivot hole formed in the shape of an elongated hole to allow rotation and position adjustment on the pivot shaft, corresponding to the wear condition of the wheel and adjusting the angle and position.

[0019] In addition, the braking bar is characterized by having an elastic body coupled thereto between the braking pads to uniformly push the braking pads toward both sides of the pivot axis. Effects of the invention

[0021] According to the dolly capable of uniform braking on a plurality of wheels according to the present invention, a braking bar is angle-adjustably coupled to a braking shaft, and braking pads for braking the wheels are angle-adjustably coupled to each side of the braking bar, so that when the braking bar moves, the angle is adjusted according to the wear condition of the wheels and simultaneously and evenly contacts them. As a result, the braking force is adjusted according to the degree of wear of each wheel, thereby enabling stable braking performance through equal braking force on each wheel, and excellent braking safety can be achieved by preventing slipping or pulling phenomena that may occur due to unbalanced braking.

[0022] In addition, braking force is applied evenly to each wheel, minimizing wear on the tires or brake pads, resulting in excellent durability and easy maintenance. Brief explanation of the drawing

[0024] FIG. 1 is a bottom perspective view of a dolly capable of equal braking on a plurality of wheels according to a preferred embodiment of the present invention. FIG. 2 is a perspective view of a braking unit according to a preferred embodiment of the present invention. FIG. 3 is a side view of a tow bar according to a preferred embodiment of the present invention. FIG. 4 is an operation diagram of a tow bar according to a preferred embodiment of the present invention. FIG. 5 is a side view of a braking unit according to a preferred embodiment of the present invention. FIG. 6 is an operation diagram of a braking unit according to a preferred embodiment of the present invention. FIG. 7 is a plan view of a rear wheel with uneven wear according to a preferred embodiment of the present invention. FIG. 8 is an operation diagram of the braking pad shown in FIG. 7 according to a preferred embodiment of the present invention. FIG. 9 is a plan view of an elastic member according to a preferred embodiment of the present invention. FIG. 10 is a rear view of a connecting portion according to a preferred embodiment of the present invention. FIG. 11 is a side view of a connecting pin according to a preferred embodiment of the present invention. Specific details for implementing the invention

[0025] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described in detail below together with the accompanying drawings.

[0026] However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0027] Hereinafter, the present invention will be described with reference to drawings illustrating a dolly capable of uniform braking on a plurality of wheels according to embodiments of the present invention.

[0028] FIG. 1 is a bottom perspective view of a dolly capable of uniform braking on a plurality of wheels according to a preferred embodiment of the present invention, FIG. 2 is a perspective view of a braking unit according to a preferred embodiment of the present invention, FIG. 3 is a side view of a tow bar according to a preferred embodiment of the present invention, FIG. 4 is an operation diagram of a tow bar according to a preferred embodiment of the present invention, FIG. 5 is a side view of a braking unit according to a preferred embodiment of the present invention, FIG. 6 is an operation diagram of a braking unit according to a preferred embodiment of the present invention, FIG. 7 is a plan view of a rear wheel with uneven wear according to a preferred embodiment of the present invention, FIG. 8 is an operation diagram of a braking pad shown in FIG. 7 according to a preferred embodiment of the present invention, FIG. 9 is a plan view of an elastic member according to a preferred embodiment of the present invention, FIG. 10 is a rear view of a connecting unit according to a preferred embodiment of the present invention, and FIG. 11 is a side view of a connecting pin according to a preferred embodiment of the present invention.

[0030] Referring to these drawings, the rotating wheel capable of uniform braking on a plurality of wheels according to the present embodiment has the feature of being able to provide uniform braking force to each wheel even if uneven wear occurs on a plurality of wheels.

[0031] A dolly (100) capable of providing such effects and capable of braking a plurality of wheels according to the present embodiment comprises a main body (110), a dolly having at least one wheel coupled to both sides, a braking shaft (131) connected to a tow bar (120) rotatably coupled to the main body (110) and reciprocating according to rotation, a braking bar (135) rotatably coupled to the end of the braking shaft (131) and angle-adjustable and in contact with the wheels (113) located on both sides, and a braking pad (137) rotatably coupled to both sides of the braking bar (135) in a position facing the wheel (113) so as to angle-adjustable and in contact with the adjacent wheel (113) according to the wear condition of the wheel (113).

[0033] The main body (110) includes a main frame (111) to allow for loading of objects. The upper surface of the main frame (111) has a flat shape, which prevents various types of objects from tilting or sliding and provides a stable loading space. Additionally, the main frame (111) is formed of a material having sufficient rigidity to safely withstand the load of the objects. For example, the main frame (111) can be made of various materials such as metal, wood, or reinforced plastic, and can be appropriately selected according to the purpose of use and the weight of the objects.

[0034] The main frame (111) of the main body (110) may have a square plate shape as a basic form. This square plate shape is easy to manufacture and allows for the efficient loading of various sizes and shapes of materials. Of course, the main frame (111) is not limited to a square plate and may be formed in various polygonal or curved shapes, such as a circle, triangle, or pentagon.

[0035] At least one wheel (113) is attached to the lower surface of the main frame (111) in the front-rear direction at the bottom of the main body (110). The wheel (113) is attached at a position adjacent to each corner of the main frame (111) so as to stably support the load of the object loaded on the main frame (111). It is preferable that each wheel (113) be formed as a pair.

[0036] The wheel (113) of the main body (110) includes a front wheel (113a) located at the front and a rear wheel (113b) located at the rear. The front wheel (113a) is rotatably coupled to enable steering. The front wheel (113a) can be steered by rotating along the center of a rotation axis (112) coupled to the lower surface of the main frame (111).

[0037] A support projection (114) for supporting a tow bar (120), which will be described later, is attached to the front of the main frame (111) of the main body (110). The support projection (114) is formed so that the tow bar (120) can be supported parallel to the main frame (111).

[0039] The tow bar (120) is for towing the main body (110) and is rotatably formed at the front end of the main frame (111) of the main body (110). A tow frame (121) is coupled to the tow bar (120) so as to be rotatably formed at the front end of the main frame (111). The rotation angle of the tow frame (121) may be limited to a certain angle. A connecting link (123) is formed at the front end of the tow frame (121), and a first pivot shaft (122) is coupled to the rear end so as to be rotatably formed on the main frame (111).

[0040] A first extension member (122a) having a first fastening hole (122b) formed therein is coupled to the first pivot shaft (122).

[0042] The braking unit (130) is for braking the rear wheel (113b) and is coupled to the lower part of the main body (110). A braking shaft (131) is disposed on the lower surface of the main frame (111) in the braking unit (130). A spring turnbuckle (132) is coupled to the front end of the braking shaft (131), and a first link member (133) is rotatably coupled to the front end of the spring turnbuckle (132). A second fastening hole (133a) is formed at the end of the first link member (133), and the second fastening hole (133a) is rotatably coupled by the first fastening hole (122b) and the first fastening pin (133b). The braking shaft (131) reciprocates according to the rotation of the tow bar (120).

[0043] A second link member (134) is connected to the rear end of the braking member (130), and a third fastening hole (134a) is formed at the end of the second link member (134). A second fastening pin (134b) is connected to the third fastening hole (134a).

[0044] In the braking unit (130), a braking bar (135) is positioned at a certain distance from the rear of the rear wheel (113b). A second extension member (135a) is coupled to the braking bar (135) at a position facing the second link member (134). A fourth fastening hole (135b) is formed at the end of the second extension member (135a) so as to be rotatably fastened to the second fastening pin (134b).

[0045] A first pivot hole (135c) is formed in the braking bar (135) of the braking unit (130) at a position adjacent to the adjacent rear wheel (113b). A second pivot shaft (136) is coupled to the first pivot hole (135c), and a braking pad (137) is rotatably coupled to the second pivot shaft (136).

[0046] Specifically, the brake pad (137) is positioned between the brake bar (135) and the rear wheel (113b) and is spaced apart from the brake bar (135) by a certain distance. An extension projection (137a) is formed so that the upper and lower ends extend to the upper and lower parts of the brake bar (135), and a second rotation hole (137b) is formed in the extension projection (137a) at a position facing the first rotation hole (135c) so as to be rotatably coupled to the second rotation shaft (136).

[0047] Here, the brake pad (137) has an area, more specifically a width, that can contact adjacent rear wheels (113b).

[0048] The braking pad (137) is rotatably coupled to the braking bar (135) at a certain distance apart, so that when the braking bar (135) moves forward, it comes into contact with the adjacent rear wheel (113b) to apply braking to the rear wheel (113b).

[0049] At this time, when wear (uneven wear) occurs on the rear wheel (113b), the angle of the brake pad (137) is rotated to correspond to the wear condition so that it can be uniformly adhered to the rear wheel (113b).

[0051] Furthermore, a connecting part (140) can be attached to the rear of the main body (110).

[0052] A connecting frame (141) is coupled to the connecting part (140) so as to be positioned at the rear end of the main frame (111) of the main body (110). A first frame (142) is coupled to the upper end of the connecting frame (141) so as to extend. The first frame (142) extends to the rear, and a first through hole (142a) is formed in the center.

[0053] A second frame (143) and a third frame (144) are joined at the lower part of the connecting frame (141), spaced apart from each other by a certain distance. The second frame (143) extends rearward, and a second through hole (143a) is formed at a position facing the first through hole (142a). The third frame (144) extends rearward, and a third through hole (144a) is formed at a position facing the second through hole (143a).

[0054] Additionally, a fourth frame (145) is formed vertically between the first frame (142) and the second frame (143) in the connecting frame (141). The upper and lower ends of the fourth frame (145) extend to the first frame (142) and the second frame (143), a first opening (145a) is formed at the upper end, and a second opening (145b) is formed at the lower end.

[0056] A connecting pin (146) is coupled to the connecting portion (140) so that it is movable in the vertical direction and rotatable by passing through the first through hole (142a), the second through hole (143a), and the third through hole (144a). The connecting pin (146) has a cylindrical shape, and the first through hole (142a), the second through hole (143a), and the third through hole (144a) also have a circular shape corresponding to the cylindrical shape of the connecting pin (146). A stepped portion (146a) is formed along the circumference of the outer surface of the connecting pin (146). The stepped portion (146a) has a ring shape and moves between the first frame (142) and the second frame (143) according to the movement of the connecting pin (146). The stepped portion (146a) has a diameter that extends to the inner wall of the first opening (145a) and the second opening (145b), and has a thickness equal to or smaller than the height of the first opening (145a) and the second opening (145b). On one side of the stepped portion (146a), a third opening (146b) is formed having a width equal to or greater than the width of the fourth frame (145).

[0057] Here, the connecting part (140) moves in the vertical direction when the third opening (146b) of the step part (146a) is positioned facing the fourth frame (145), and rotates while the step part (146a) is positioned at the first opening (145a) or the second opening (145b) so that the third opening (146b) is positioned opposite the fourth frame (145), thereby fixing the position by the step part (146a) being caught on the first opening (145a) or the second opening (145b).

[0058] When the connecting pin (146) of the connecting part (140) moves downward, the step portion (146a) is positionally restricted by being caught on the upper surface of the second frame (143), and the lower end of the connecting pin (146) is positioned within the third through hole (144a) or positioned downward. When moving upward, the step portion (146a) is positionally restricted by being caught on the lower surface of the first frame (142), and the lower end of the connecting pin (146) is positioned within the second through hole (143a) or positioned upward.

[0059] Additionally, a gripping portion (146c) is attached to the upper part of the connecting portion (140). For example, the gripping portion (146c) has a square ring shape.

[0060] A restraining member (147) is attached to one side of the connecting member (140) to prevent the downwardly moved connecting pin (146) from moving upward. A spacing frame (147a) is attached to the restraining member (147) on one side of the upper surface of the second frame (143) so as to be spaced apart from each other. A third pivot shaft (147b) is attached between the spacing frames (147a), and a restraining plate (147c) is rotatably attached to the third pivot shaft (147b). The restraining plate (147c) extends to an adjacent position so that one end catches on the step portion (146a), and an inclined surface (147d) is formed at the end. The inclined surface (147d) is formed on the upper and lower surfaces so that the end of the restraining plate (147c) is formed into a triangular shape.

[0061] A stopper (147f) is attached between the spacing frames (147a) of the control section (147) at a position adjacent to the inclined surface (147d). At this time, the control plate (147c) rotates in one direction due to an external force, and when it rotates in the other direction due to its own weight, it catches on the stopper (147f) at a certain angle, thereby limiting the rotation angle.

[0062] Here, the stopper plate (147c) is rotated to a position where it catches on the catch (147f) by its own weight, and its end is extended to the step portion (146a) of the connecting pin (146). When the connecting pin (146) is positioned downward and moves upward, the step portion (146a) catches on the stopper plate (147c), thereby restricting upward movement. Accordingly, when the connecting pin (146) moves upward, it is preferable to rotate the stopper plate (147c) in one direction by an external force so that its end is positioned so that it does not interfere with the step portion (146a) by the inclined surface (147d).

[0063] Additionally, when the connecting pin (146) moves downward while in an upward position, the step portion (146a) presses against the inclined surface (147d), causing the stopping plate (147c) to rotate in one direction, and the step portion (146a) of the connecting pin (146) moves downward. When the step portion (146a) moves downward, the stopping plate (147c) rotates back in the other direction by its own weight and returns to its original position.

[0064] Additionally, the connecting pin (146) can be moved downward not only by its own weight but also by an elastic body coupled between the first frame (142) and the step portion (146a). The elastic body can be coupled to be wound around the connecting pin (146) by a coil spring.

[0066] Furthermore, the first pivot hole (135c) of the brake pad (137) may be formed in an elongated shape to allow for more precise and diverse angle adjustments. The first pivot hole (135c) has a long side in the front-rear direction, and the second pivot shaft (136) is coupled to move in the front-rear direction so as to allow for more flexible movement. A cushioning member (139) for cushioning impact is coupled to the rear end of the second pivot hole (137b). For example, the cushioning member (139) may be formed of rubber or silicone material.

[0067] Additionally, as the braking pad (137) moves flexibly, an elastic member (138) may be attached so that it does not move arbitrarily due to external impact, thereby preventing wear or noise or vibration caused by impact. The elastic member (138) is coupled between the second pivot shaft (136) and the second pivot hole (137b), with one side coupled to the first inlet hole (136a) formed in the second pivot shaft (136) and the other side coupled to the second inlet hole (137c) formed at the front end of the second pivot hole (137b).

[0069] Furthermore, the control plate (147c) can be rotated by external force or self-weight, as well as rotated or fixed in position by magnetism.

[0070] Specifically, a first magnetic body (143b) having a first pole is coupled to the outer upper surface of the second frame (143), and a second magnetic body (146d) having a second pole identical to the first magnetic body (143b) is coupled to the lower surface of the stepped portion (146a) of the connecting pin (146).

[0071] For example, the first pole of the first magnetic body (143b) is formed as an S pole, and the second pole of the second magnetic body (146d) is formed as an S pole.

[0072] Inside the interruption plate (147c), a third magnetic body (147e) is coupled to have a third pole that is the same as the first pole on one side of the interruption plate (147c), and a fourth pole that is opposite to the third pole on the other side.

[0073] For example, the first pole of the third magnetic body (147e) is formed as an S pole, and the second pole is formed as an N pole.

[0074] Accordingly, when the control plate (147c) rotates in the other direction due to its own weight and the other end is supported on the second frame (143), the first pole of the first magnetic body (143b) and the fourth pole of the third magnetic body (147e) are magnetically coupled to each other and fixed.

[0075] And, when the connecting pin (146) is positioned upward and moves downward, the inclined surface (147d) of the interrupting plate (147c) rotates in one direction due to the repulsive force generated by the second pole of the second magnetic body (146d) coupled to the step portion (146a) and the third pole of the third magnetic body (147e) coupled to the interrupting plate (147c), in addition to the load and external force of the connecting pin (146).

[0077] Hereinafter, the operation of the dolly (100) capable of equal braking on a plurality of wheels of the present invention will be explained.

[0078] A tow bar (120) is rotatably coupled to the front end of the main body (110) by a first pivot shaft (122), so as to be attached to a tow vehicle of various heights, and also brakes the rear wheel (113b) of the main body (110) according to the angle of rotation. When the tow bar (120) moves downward by the support jaw (114), it is positioned parallel to the main body (110), and when it rotates upward by approximately 38 degrees, the braking part (130) is pulled according to the rotation, thereby applying braking to the rear wheel (113b). The angle of braking as the tow bar (120) rotates is approximately 38 degrees, but a deviation of approximately 2 degrees may occur depending on the type or wear condition of the rear wheel (113b).

[0079] The braking unit (130) can maintain traction regardless of deviation from the rear wheel (113b) through a spring turnbuckle (132), and as the braking unit (130) moves back and forth, the braking bar (135) and the braking pad (137) can rotate to correspond to the deviation of the rear wheel (113b) and be uniformly in contact.

[0080] Additionally, the braking pad (137) is coupled to the first pivot hole (135c), which is in the shape of an elongated hole, so that it can move and rotate in the forward and backward directions, allowing for more flexible angle adjustment. In order to prevent easy movement due to external factors through flexibility, an elastic member (138) is coupled between the first pivot hole (135c) and the second pivot shaft (136), and a cushioning member (139) is coupled so that the impact can be cushioned.

[0081] Meanwhile, a connecting part (140) is attached to the rear of the main body (110) to increase usability by additionally connecting other devices or loads. The connecting pin (146) of the connecting part (140) is capable of vertical movement and rotation, and a stepped portion (146a) formed on the connecting pin (146) is fixed to the first frame (142) and the second frame (143) of the connecting frame (141) so as not to detach. The stepped portion (146a) can be fixed by being caught within the first opening (145a) and the second opening (145b) of the fourth frame (145), or can be moved in the vertical direction when the third opening (146b) is positioned to face the fourth frame (145).

[0082] After the connecting pin (146) is moved downward, the control part (147) is operated to prevent it from moving upward arbitrarily, and when the connecting pin (146) is to be moved upward again, the control plate (147c) is pressed with an external force to move the inclined surface (147d) so that it does not catch on the step part (146a), and then the connecting pin (146) is moved.

[0083] Here, the interruption plate (147c) may be magnetically coupled to the second frame (143) by the third magnetic body (147e) or rotated by the repulsive force due to the second magnetism of the step portion (146a).

[0085] According to the dolly capable of uniform braking on a plurality of wheels according to the present invention, a braking bar is angle-adjustably coupled to a braking shaft, and braking pads for braking the wheels are angle-adjustably coupled to each side of the braking bar, so that when the braking bar moves, the angle is adjusted according to the wear condition of the wheels and simultaneously and evenly contacts them. As a result, the braking force is adjusted according to the degree of wear of each wheel, thereby enabling stable braking performance through equal braking force on each wheel, and excellent braking safety can be achieved by preventing slipping or pulling phenomena that may occur due to unbalanced braking.

[0086] In addition, braking force is applied evenly to each wheel, minimizing wear on the tires or brake pads, resulting in excellent durability and easy maintenance.

[0088] A person skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0089] 100: Dolly 110: Main body 111: Main frame 112: Rotation axis 113: Wheel 113a: Front wheel 113b: Rear wheel 114: Support jaw 120: Tow bar 121: Toe frame 122: First pivot axis 122a: First extension member 122b: First fastening hole 123: Link 130: Braking unit 131: Braking shaft 132: Spring turnbuckle 133: First link member 133a: Second fastening hole 133b: First fastening pin 134: Second link member 134a: 3rd fastening hole 134b: 2nd fastening pin 135: Brake bar 135a: Second extension member 135b: 4th fastening hole 135c: 1st pivot hole 136: Second pivot shaft 136a: First inlet hole 137: Brake pad 137a: Extension bump 137b: 2nd pivot hole 137c: 2nd inlet hole 138: Elastic member 139: Cushioning member 140: Connection part 141: Connection frame 142: First frame 142a: First through hole 143: Second frame 143a: Second through hole 143b: First magnetic body 144: Third frame 144a: 3rd penetration hole 145: 4th frame 145a: 1st opening 145b: 2nd opening 146: Connecting pin 146a: Step portion 146b: Third opening 146c: Grasping part 146d: Second magnetic body 147: Intermittent part 147a: Separation frame 147b: Third pivot axis 147c: Stop sign 147d: Sloping surface 147e: Third magnetic material 147f: Stopper

Claims

Claim 1 A dolly having at least one wheel coupled to both sides, a braking shaft connected to a tow bar rotatably coupled to a main body and reciprocating as it rotates; and a braking bar rotatably coupled to the end of the braking shaft and angle-adjustable and in contact with the wheels located on both sides according to the wear condition of the wheels; braking pads are rotatably coupled to both sides of the braking bar in a position facing the wheels and angle-adjustable and in contact with the adjacent wheels according to the wear condition of the adjacent wheels; the braking pads are rotatably coupled by a pivot axis in a position facing the center of the adjacent wheels, and the pivot axis is positioned parallel to the center between a plurality of adjacent wheels; a connecting part is further coupled to the rear of the main body, and the connecting part comprises: a connecting frame coupled to the end of the main body; a first frame coupled to the upper end of the connecting frame and having a first through hole formed therein; a second frame and a third frame coupled to the lower end of the connecting frame spaced apart from each other and extending rearward, with a second through hole and a third through hole respectively formed in a position facing the first through hole; a fourth frame formed vertically between the first frame and the second frame, with a first opening formed at the upper end and a second opening formed at the lower end; the first through hole, A dolly capable of uniform braking on a plurality of wheels, comprising: a connecting pin that is coupled through a second through hole and a third through hole, is movable and rotatable in the vertical direction, and intermittently moves between the second frame and the third frame as it moves, and is coupled to a stepped portion having a third opening formed on one side between the first frame and the second frame, so as to be fixed in position by engaging with the first opening and the second opening as it rotates; and an intermittent portion rotatably coupled to one side of the second frame, which intermittently moves the connecting pin from one direction to the other, and is pushed and rotated by the stepped portion when it moves from the other direction to the one direction. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete

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