Assist device

Abstract

To provide an assist device that ensures good operability while minimizing the bulkiness required for installation space. [Solution] The assist mechanism 11 includes a mounting base 13 fixed to the bottom surface of the base 2 of the hand truck 1, an assist lever 30 rotatably connected to the mounting base 13, and an assist link 33 connected to the assist lever 30, which receives a reaction force from the ground surface FL that becomes an assist force when the assist lever 33 is rotated to push the hand truck 1 forward. The lock mechanism 12 includes a lock lever 70 rotatably connected to the mounting base 13, which restricts the movement of the assist lever 30 when the lock lever 70 is rotated, and maintains a state in which the assist link 33 contacts the ground surface FL and the hand truck 1 is braked. The lock lever 70 is positioned to overlap with the assist lever 30 in a plan view.

Description

Technical Field

[0001] The present invention relates to an assist device.

Background Art

[0002] In Patent Document 1, when the assist footrest part of the foot-operated assist lever part is depressed, the foot-operated assist lever part rotates about the first connecting shaft, and the assist wheel support part descends. At this time, an assist device is disclosed in which an assist operation guide pin provided on the assist wheel support part pushes out a road surface kicking part backward by an assist force generation rear case part provided on the base part to obtain an assist force forward. Further, this assist device includes a foot-operated brake lever part provided with a brake footrest part that the user steps on with the foot when stopping the handcart.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above assist device, since the brake footrest part of the foot-operated brake lever part is arranged at a protruding position on the side of the assist footrest part of the assist lever part, the installation space becomes large.

[0005] In view of the above circumstances, the present invention has been made, and an object thereof is to provide an assist device capable of suppressing the increase in installation space while ensuring good operability.

Means for Solving the Problems

[0006] In order to achieve the above object, the assist device of the present invention is An assist device that provides assisting force to a hand truck capable of traveling on a ground surface, A mounting base fixed to the bottom surface of the base of the aforementioned hand truck, An assist mechanism comprising: an assist lever rotatably connected to the mounting base; and an assist link connected to the assist lever, which receives a reaction force from the ground surface that provides an assisting force when the assist lever is rotated and pushes the hand truck forward; A locking mechanism having a lock lever rotatably connected to the mounting base, wherein the movement of the assist lever is restricted when the lock lever is rotated, and the assist link contacts the ground surface, maintaining the hand truck in a braked state, Equipped with, The lock lever is positioned in a location that overlaps with the assist lever in a plan view. With this assist device configuration, by rotating the assist lever of the assist mechanism, the hand truck can be easily pushed forward by the assist force resulting from the reaction force from the ground. Furthermore, by rotating the lock lever of the lock mechanism, the assist link can be brought into contact with the ground, maintaining a state where the brakes are applied to the hand truck. Furthermore, in this assist device, the lock lever of the locking mechanism is positioned so that it overlaps with the assist lever of the assisting mechanism in a plan view. Therefore, compared to a structure in which the lock lever is positioned so as to protrude laterally from the assist lever, the bulkiness required for installation space can be reduced. In addition, contact between the lock lever and the foot is reduced when operating the assist lever with the foot. In short, it is possible to reduce the bulkiness of the installation space while ensuring good operability.

[0007] Furthermore, the lock lever may have a lock pin, and the movement of the assist lever may be restricted by engaging the lock pin between the assist lever and the assist link. With this type of assist device, the movement of the assist lever can be easily restricted by rotating the lock lever to engage the lock pin between the assist lever and the assist link, allowing the assist link to contact the ground surface and maintain a state where the brakes are applied to the handcart.

[0008] Furthermore, the assist link is connected to the assist lever via the first link and the second link. The first link and the second link have one end connected to the assist lever, and the other ends are connected to each other and to the upper end of the assist link. The toggle mechanism may be configured by the first link, the second link, and the assist link. In this assist device configuration, the toggle mechanism is formed by the first link, the second link, and the assist link. Therefore, the assist force resulting from the reaction force received by the assist link from the ground surface can be amplified, making it possible to easily push the handcart forward and start moving smoothly.

[0009] Furthermore, the assist lever may have a pair of side plates spaced apart, with the first link, the second link, and the assist link positioned between the side plates. This configuration of the assist device allows for a compact design while enabling the toggle mechanism to be constructed using the first link, the second link, and the assist link.

[0010] Furthermore, the mounting base has a support pin that rotatably supports the lock lever. The first link is positioned below the support pin and may have a relief recess to avoid interference with the support pin. With this configuration of the assist device, the first link has a relief recess to avoid interference with the support pin provided on the mounting base that rotatably supports the lock lever, thereby increasing the range of motion of the first link. As a result, the toggle mechanism, which is composed of the first link, the second link, and the assist link, can be operated smoothly.

[0011] Furthermore, the assist link may have an assist leg at its lower end that is movable forward and backward relative to the assist link, and the assist leg may be biased by a biasing member in a direction that protrudes from the lower end of the assist link. With this configuration of the assist device, the biasing force of the biasing member allows the assist foot to make balanced contact with the ground surface during assistance or braking. As a result, the assist mechanism can provide efficient assistance, and braking can be applied stably. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an assist device that can reduce the bulkiness of the installation space while ensuring good operability. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a side view of the assist device according to this embodiment. [Figure 2] Figure 2 is a plan view of the assist device according to this embodiment. [Figure 3] Figure 3 is a rear view of the assist device according to this embodiment. [Figure 4] Figure 4 is a longitudinal cross-sectional view of the assist device attached to the hand truck, along the front-to-back direction. [Figure 5] Figure 5 is a longitudinal cross-sectional view along the front-to-back direction of the assist device, illustrating the operation of the assist mechanism. [Figure 6] Figure 6 is a longitudinal cross-sectional view along the front-to-back direction of the assist device, illustrating the operation of the assist mechanism. [Figure 7]FIG. 7 is a longitudinal sectional view along the front-rear direction of an assist device for explaining the operation of the lock mechanism.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of an assist device 10 according to the present embodiment. FIG. 2 is a plan view of the assist device 10 according to the present embodiment. FIG. 3 is a rear view of the assist device 10 according to the present embodiment. FIG. 4 is a longitudinal sectional view along the front-rear direction of the assist device 10 mounted on the hand truck 1.

[0015] (Overall Configuration) As shown in FIGS. 1 to 4, the assist device 10 according to the present embodiment includes an assist mechanism 11 and a lock mechanism 12. The assist device 10 includes a mounting base 13, and the assist mechanism 11 and the lock mechanism 12 are assembled to the mounting base 13.

[0016] The assist device 10 is attached to the hand truck 1 (see FIG. 4). The hand truck 1 includes a rectangular plate-shaped pedestal 2, and a load can be placed on the upper surface of the pedestal 2. Four wheels 3 are attached to the bottom surface of the pedestal 2. The wheels 3 are arranged at the four corners of the bottom surface of the pedestal 2. The hand truck 1 can travel on the ground contact surface FL by the wheels 3 attached to the bottom surface of the pedestal 2. Further, a handle 4 is erected at the rear part of the pedestal 2. The hand truck 1 travels forward when the user grips the handle 4 and pushes it forward.

[0017] Hereinafter, in each drawing, the front side in the traveling direction of the hand truck 1 is indicated by FR, and the rear side in the traveling direction of the hand truck 1 is indicated by BC. Also, the front side in the traveling direction of the hand truck 1 is regarded as the front, and the rear side in the traveling direction of the hand truck 1 is regarded as the rear. The portion on the front side in the traveling direction of the hand truck 1 in each member will be described as the front part or the front end part, and the portion on the rear side in the traveling direction of the hand truck 1 in each member will be described as the rear part or the rear end part.

[0018] The assist device 10 is attached to the bottom surface of the base 2 of the hand truck 1. The assist device 10 is located at the rear of the base 2, for example, positioned in the center of the base 2 in the width direction.

[0019] (Mounting base) The mounting base 13 is formed in the shape of a rectangular plate in plan view. This mounting base 13 has mounting holes 20 at its four corners, and is fixed to the bottom surface of the base 2 by screws (not shown) inserted into these mounting holes 20. A pair of brackets 21 are fixed to the lower part of the front side of the mounting base 13. The mounting base 13 also has a pair of stays 22 at the lower part of the rear side. These stays 22 are formed by cutting and bending the mounting base 13. Furthermore, the strength of this mounting base 13 is improved by forming a stepped recess 13a in its central part.

[0020] (Assist mechanism) The assist mechanism 11 includes an assist lever 30, a first link 31, a second link 32, and an assist link 33.

[0021] The assist lever 30 has a pair of side plate portions 35 that face each other. The assist lever 30 has a plate-shaped foot-operated piece 36 at its rear end that is pressed down by the user. The assist lever 30 is constructed by connecting the rear ends of the pair of side plate portions 35 with the foot-operated piece 36. The first link 31, the second link 32, and the assist link 33 are arranged between the side plate portions 35 of the assist lever 30.

[0022] The assist lever 30 is formed in a curved shape in side view, bulging downwards when viewed from the side. The front end of the assist lever 30 is rotatably connected to the bracket 21 of the mounting base 13 by a first connecting shaft 41. The assist lever 30 has an arc-shaped recessed engagement recess 37 on its upper part near the rear end. The assist lever 30 also has an engagement projection 38 that protrudes upwards on the front end side of the engagement recess 37. The strength of this assist lever 30 is improved by forming a stepped recess 35a in the side plate portion 35.

[0023] The first link 31 is formed in a straight line, and its front end is rotatably connected to the bracket 21 of the mounting base 13 by a first connecting shaft 41, together with the front end of the assist lever 30. The first link 31 has a relief recess 40 extending along its longitudinal direction at its upper part in the center of its longitudinal direction.

[0024] The second link 32 is formed in a straight line, and its front end is connected to the middle part of the assist lever 30 by a second connecting shaft 42. The rear end of the second link 32 is connected to the rear end of the first link 31 by a third connecting shaft 43. The second link 32 has a contact plate portion 44 at the lower part in the center in the longitudinal direction.

[0025] The assist link 33 is formed in a straight line and is arranged along the vertical direction. The upper end of the assist link 33 is rotatably connected to the rear ends of the first link 31 and the second link 32 by a third connecting shaft 43.

[0026] The assist link 33 is equipped with an assist leg 50 at its lower end. This assist leg 50 comprises a sliding plate 51 and an assist plate 52, and is capable of moving forward and backward relative to the assist link 33.

[0027] The slide plate 51 is positioned to protrude from the lower end of the assist link 33. A long hole 51a is formed in the slide plate 51, and a pin 53 provided on the assist link 33 is inserted through this long hole 51a. As a result, the slide plate 51 is slidable relative to the assist link 33 within the longitudinal range in which the pin 53 can move within the long hole 51a. A coil spring 54 is also installed between the assist link 33 and the slide plate 51, and this coil spring 54 biases the slide plate 51 downward relative to the assist link 33.

[0028] The assist plate 52 is connected to the lower end of the slide plate 51. A connecting piece 55 is erected on the upper surface of the assist plate 52, and this connecting piece 55 is connected to the lower end of the slide plate 51 by a pin 56. The lower end of the slide plate 51 has an arc-shaped corner on one side in the width direction. As a result, the assist plate 52 is rotatable around the pin 56 towards the side of the slide plate 51 where the arc-shaped corner is formed. A torsion spring 57 is attached to the connection point between the slide plate 51 and the assist plate 52, and this torsion spring 57 biases the assist plate 52 toward the other corner. As a result, the assist plate 52 is positioned perpendicular to the slide plate 51. In addition, a grip material 58 such as rubber is attached to the lower surface of the assist plate 52.

[0029] The assist mechanism 11 includes a first spring 61 and a second spring 62. Both the first spring 61 and the second spring 62 are made of coil springs.

[0030] The first spring 61 has one end locked to the second connecting shaft 42, which connects the assist lever 30 and the second link 32, and the other end locked to the middle section of the assist link 33. The elastic force of this first spring 61 pulls the middle section of the assist link 33 forward. The assist link 33, with its middle section pulled forward by the first spring 61, comes into contact with a contact plate 44 provided on the second link 32, and its forward movement is restricted.

[0031] The second spring 62 has one end locked to the second connecting shaft 42 that connects the assist lever 30 and the second link 32, and the other end locked to a support pin 63 provided on the stay 22 of the mounting base 13. The elastic force of this second spring 62 pulls the assist lever 30 upward.

[0032] (Locking mechanism) The locking mechanism 12 has a locking lever 70. The locking lever 70 is formed in a substantially U-shape with side plate portions 72 extending downward from both side edges of the flat plate portion 71. The locking lever 70 has a hole 71a formed in the flat plate portion 71, which reduces weight and avoids interference with the rear end of the first link 31, the rear end of the second link, and the upper end of the assist link 33 (see Figures 2 and 4).

[0033] The lock lever 70 and the assist lever 30 share the same centerline CL in the width direction. Furthermore, the lock lever 70 is positioned to overlap with the assist lever 30 in a plan view (see Figures 2 and 3).

[0034] The lock lever 70 is rotatably supported at its front end by a support pin 63 provided on a stay 22 of the mounting base 13. The lock lever 70 has a plate-shaped operating piece 73 at its rear end that is operated by the user. A torsion spring 74 is installed at the connection point between the lock lever 70 and the stay 22. As a result, the rear end of the lock lever 70 is biased upward by the torsion spring 74, and the flat plate portion 71 is positioned in the same plane as the mounting base 13.

[0035] The lock lever 70 has a lock pin 75. This lock pin 75 is located on the rear end side of the lock lever 70 and spans across the side plate portion 72. This lock pin 75 engages with an engagement recess 37 of the assist lever 30, which is pulled upward by the second spring 62. As a result, the upward movement of the assist lever 30 by the elastic force of the second spring 62 is restricted by the lock pin 75 engaging with the engagement recess 37, and the assist lever 30, the first link 31, the second link 32, and the assist link 33 are positioned in their initial positions. In this initial position, the support pin 63 is positioned in a relief recess 40 of the first link 31, which is located below the support pin 63 that supports the lock lever 70.

[0036] Next, the operation of the assist device 10 with the above configuration will be described.

[0037] (Operation of the assist mechanism) Figures 5 and 6 are longitudinal cross-sectional views of the assist device 10 along the front-rear direction, illustrating the operation of the assist mechanism 11.

[0038] When the user presses down on the foot-operated piece 36 on the assist lever 30 of the assist device 10, as shown in Figure 5, the assist lever 30 rotates in one direction (arrow Ra in Figure 5) around the first connecting shaft 41 against the biasing force of the second spring 62, causing the assist lever 30 to move downward. As a result, the first link 31, the second link 32, and the assist link 33 rotate together with the assist lever 30 in one direction (arrow Ra in Figure 5) around the first connecting shaft 41. Then, the assist foot 50 of the assist link 33 moves toward the ground surface FL, and the grip material 58 of the assist plate 52 of the assist foot 50 comes into contact with the ground surface FL. Furthermore, as the assist link 33 moves downward and the grip material 58 of the assist plate 52 is pressed against the ground surface FL, the coil spring 54 of the assist foot 50 is compressed, and the slide plate 51 is pushed toward the assist link 33. As a result, the assist leg 50 is pressed against the ground surface FL, and the grip material 58 of the assist plate 52 is in close contact with the ground surface FL.

[0039] From this state, when the user further presses down on the foot pedal 36, as shown in Figure 6, the assist lever 30 rotates further in one direction (arrow Ra in Figure 5) around the first connecting shaft 41 against the biasing force of the second spring 62, and the rotation of the assist lever 30 causes the second connecting shaft 42 to move forward, and the second link 32 connected by this second connecting shaft 42 also moves forward. At this time, the assist link 33 has its assist foot 50 pressed against the ground surface FL, and the grip material 58 of the assist plate 52 is in close contact with the ground surface FL. Therefore, the lower end of the assist link 33, which has the assist foot 50, is maintained in a position where it is in contact with the ground surface FL due to the frictional force. As a result, the upper end of the assist link 33, which is connected to the third connecting shaft 43, moves forward and rotates relatively upward (arrow Rb in Figure 6) around the third connecting shaft 43 against the biasing force of the first spring 61. Furthermore, in the assist leg 50 where the grip material 58 of the assist plate 52 is in close contact with the ground surface FL, the assist plate 52 rotates against the biasing force of the torsion spring 57 relative to the assist link 33. This maintains the grip material 58 of the assist plate 52 in close contact with the ground surface FL.

[0040] In this way, as the upper end of the assist link 33, which is connected to the third connecting shaft 43, moves forward, a pushing force is generated in the assist link 33 that pushes it relatively backward. At this time, since the assist plate 52 of the assist leg 50 of the assist link 33 is in close contact with the ground surface FL, the pushing force generated in the assist link 33 is transmitted as an assist force to the mounting base 13 via the first link 31, the second link 32, and the assist lever 30. As a result, the hand truck 1 is pushed forward by the assist force consisting of the reaction force from the ground surface FL caused by the pushing force generated in the assist link 33.

[0041] Here, the assist mechanism 11 is configured as a toggle mechanism by the first link 31, the second link 32, and the assist link 33. Therefore, when the foot-operated piece 36 of the assist lever 30 is pressed down, the assist link 33 is rotated relatively upward (in the direction of arrow Rb in Figure 6) around the third connecting shaft 43, and as the angle between the first link 31 and the assist link 33 and the angle between the second link 32 and the assist link 33 gradually increases, the assist force pushing the hand truck 1 forward is amplified. Therefore, by pressing down the foot-operated piece 36 of the assist lever 30, the user can easily push the hand truck 1 forward with the large assist force generated by the assist mechanism 11 and start moving smoothly.

[0042] When the user releases the depressing portion 36 of the assist lever 30, the assist mechanism 11 is activated by the second spring 62, which pulls up the second connecting shaft 42, and the assist link 33 is pulled forward by the first spring 61. As a result, the assist lever 30, the first link 31, the second link 32, and the assist link 33 are pulled up, and the assist link 33 comes into contact with the contact plate portion 44 of the second link 32. As a result, the assist lever 30, the first link 31, the second link 32, and the assist link 33 are returned to their initial positions, and the assist plate 52 of the assist foot 50 is positioned away from the ground surface FL (see Figure 4).

[0043] (Operation of the locking mechanism) Figure 7 is a longitudinal cross-sectional view of the assist device 10 along the front-to-back direction, illustrating the operation of the locking mechanism 12.

[0044] When the user presses down the operating piece 73 on the lock lever 70 of the assist device 10, the lock lever 70 rotates downward (in the direction of the arrow Rc in Figure 7) around the support pin 63 against the biasing force of the torsion spring 74, as shown in Figure 7. As a result, the lock pin 75 of the lock lever 70, which is engaged with the engagement recess 37 of the assist lever 30, slides along the upper edge of the assist lever 30 and pushes the assist lever 30 down. As a result, the first link 31, the second link 32, and the assist link 33 rotate together with the assist lever 30 around the first connecting shaft 41 in one direction (in the direction of the arrow Ra in Figure 5). Then, the assist leg 50 of the assist link 33 moves toward the ground surface FL, and the grip material 58 of the assist plate 52 of this assist leg 50 comes into contact with the ground surface FL. Furthermore, as the assist link 33 moves downward and the grip material 58 of the assist plate 52 is pressed against the ground surface FL, the coil spring 54 of the assist leg 50 is compressed and the slide plate 51 is pushed against the assist link 33. As a result, the assist leg 50 is pressed against the ground surface FL and the grip material 58 of the assist plate 52 is in close contact with the ground surface FL. As a result, the frictional force between the grip material 58 of the assist plate 52 and the ground surface FL causes the hand truck 1 equipped with the assist device 10 to be braked against the ground surface FL.

[0045] In this brake state, the lock pin 75 of the lock lever 70 overcomes the engaging projection 38 of the assist lever 30, moves forward of the engaging projection 38, and engages with the assist lever 30 and the assist link 33 by interlocking with the engaging projection 38. This restricts the upward movement of the assist lever 30, locks the assist leg 50 of the assist link 33 in a position pressed against the ground surface FL, and maintains the brake state of the hand truck 1. In this brake locked state, the coil spring 54 of the assist leg 50 is not fully compressed and remains in a state where it can be further compressed.

[0046] In the brake locked state described above, when the user presses down on the foot pedal 36 of the assist lever 30, the coil spring 54 of the assist foot 50 is compressed and the assist lever 30 moves downward. This releases the engagement of the lock pin 75 of the lock lever 70, which was engaged between the assist lever 30 and the assist link 33, by the engaging projection 38, and the lock lever 70 is pulled up by the biasing force of the torsion spring 74. As a result, the brake lock by the lock mechanism 12 is released.

[0047] After the brakes are released, when the user takes their foot off the foot 36 of the assist lever 30, the assist lever 30, the first link 31, the second link 32, and the assist link 33 are pulled up and returned to their initial positions, separating the assist foot 50 of the assist link 33 from the ground surface FL. This releases the brake applied by the assist foot 50 of the assist link 33.

[0048] In contrast, when the user further presses the foot pedal 36 of the assist lever 30 after the brake lock has been released, the assist lever 30 rotates further in one direction (arrow Ra direction in Figure 5) around the first connecting shaft 41 against the biasing force of the second spring 62. This rotation of the assist lever 30 causes the second connecting shaft 42 to move forward, and the second link 32 connected by this second connecting shaft 42 also moves forward. As a result, the upper end of the assist link 33 connected to the third connecting shaft 43 moves forward, generating a pushing force that pushes the assist link 33 backward. This pushing force creates an assist force that pushes the hand truck 1 forward.

[0049] As described above, according to the assist device 10 of this embodiment, by rotating the assist lever 30 of the assist mechanism 11, the hand truck 1 can be easily pushed forward by the assist force resulting from the reaction force from the ground surface FL. Furthermore, by rotating the lock lever 70 of the lock mechanism 12, the assist leg 50 of the assist link 33 can be brought into contact with the ground surface FL, maintaining a state in which the hand truck 1 is braked.

[0050] Furthermore, in the assist device 10 according to this embodiment, the lock lever 70 of the lock mechanism 12 is positioned to overlap with the assist lever 30 of the assist mechanism 11 in a plan view. Therefore, compared to the case where the lock lever 70 is positioned to protrude laterally from the assist lever 30, the bulkiness of the installation space can be reduced. In addition, contact between the lock lever 70 and the foot can be reduced when operating the assist lever 30 with the foot. In other words, the bulkiness of the installation space can be reduced while ensuring good operability.

[0051] In particular, the locking mechanism 12 allows the movement of the assist lever 30 to be easily restricted by rotating the lock lever 70 to engage the lock pin 75 between the assist lever 30 and the assist link 33, thereby maintaining a state where the assist leg 50 of the assist link 33 contacts the ground surface FL and the hand truck 1 is braked.

[0052] Furthermore, the assist mechanism 11 is configured as a toggle mechanism by the first link 31, the second link 32, and the assist link 33. Therefore, the assist force resulting from the reaction force received by the assist link 33 from the ground surface FL can be amplified, making it possible to easily push the hand truck 1 forward and start moving smoothly.

[0053] Furthermore, since the first link 31, the second link 32, and the assist link 33 are arranged between the side plates 35 of the assist lever 30, the toggle mechanism can be constructed using the first link 31, the second link 32, and the assist link 33 while maintaining a compact design.

[0054] Furthermore, since the first link 31 has a relief recess 40 to avoid interference with the support pin 63 provided on the mounting base 13 that rotatably supports the lock lever 70, the range of motion of the first link 31 can be increased. In other words, the first link 31 can be moved as far upward as possible without interfering with the support pin 63, thereby enabling the toggle mechanism, which is composed of the first link 31, the second link 32, and the assist link 33, to operate smoothly.

[0055] Furthermore, the assist link 33 has a movable assist leg 50 that is biased by a coil spring 54 to protrude from the lower end of the assist link 33. Therefore, when assisting or braking with the assist mechanism 11, the biasing force of the coil spring 54 can bring the assist leg 50 into balanced contact with the ground surface FL. This allows the assist mechanism 11 to provide efficient assistance and also enables stable braking. [Explanation of Symbols]

[0056] 1 Hand truck 2 bases 10 Assist device 11 Assist mechanism 12 Locking mechanism 13 Mounting base 30 Assist Lever 31. Link 1 32. Second Link 33 Assist Link 35 Side plate part 40 Recessed recess 50 Assist Leg 54. Coil spring (biasing member) 63 Support pins 70 Locking Lever 75 lock pins FL ground plane

Claims

1. An assist device that provides assisting force to a hand truck capable of traveling on a ground surface, A mounting base fixed to the bottom surface of the base of the aforementioned hand truck, An assist mechanism comprising: an assist lever rotatably connected to the mounting base; and an assist link connected to the assist lever, which receives a reaction force from the ground surface that provides an assisting force when the assist lever is rotated and pushes the hand truck forward; A locking mechanism having a lock lever rotatably connected to the mounting base, wherein the movement of the assist lever is restricted when the lock lever is rotated, and the assist link contacts the ground surface, maintaining the hand truck in a braked state, Equipped with, The lock lever is positioned in a location that overlaps with the assist lever in a plan view. Assist device.

2. The lock lever has a lock pin, and by engaging the lock pin between the assist lever and the assist link, it restricts the movement of the assist lever. The assist device according to claim 1.

3. The assist link is connected to the assist lever via the first link and the second link. The first link and the second link have one end connected to the assist lever, and the other ends are connected to each other and to the upper end of the assist link. The toggle mechanism is formed by the first link, the second link, and the assist link. The assist device according to claim 1.

4. The assist lever has a pair of side plates spaced apart, and the first link, the second link, and the assist link are arranged between the side plates. The assist device according to claim 3.

5. The mounting base has a support pin that rotatably supports the lock lever, The first link is positioned below the support pin and has a relief recess to avoid interference with the support pin. The assist device according to claim 3 or claim 4.

6. The assist link has an assist foot at its lower end that is movable forward and backward relative to the assist link, and the assist foot is biased by a biasing member in a direction that protrudes from the lower end of the assist link. The assist device according to claim 1.

Images