An electric power-assisted handcart and its operation method

Abstract

The present invention discloses an electric-assisted handcart, which includes a vehicle frame, an electric lifting mechanism, an electric push rod, and a guide rod; the electric lifting mechanism includes a motor, a lead screw, a fork rod, and wheels; when encountering stairs, the operator still holds the handle and pushes the handcart until the guide wheel abuts against the side of the first step. After adjusting the position of the wheels relative to the guide rod according to the step width, the handcart is fixed. The motor drives the lifting mechanism to rise, lifting the handcart and the heavy object together to the first step, and the guide rod rises to the second step. The electric push rod pulls the entire lifting mechanism towards the handle direction. With the cooperation of the operator, the entire handcart moves forward, and the wheels move to the first step; push the handcart, the motor lead screw drives the lifting mechanism to retract, and the operator forces the handcart until the guide rod abuts against the side of the second step; repeat the above actions, and the handcart can complete the task of climbing stairs with the assistance of the motor and the operator.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric-assisted trolleys, and more particularly, relates to an electric-assisted trolley with a function of assisting in going upstairs. Background Art

[0002] A trolley is a device used by operators to carry heavy objects. Most of them are two-wheel structures, which are small in size, strong in load capacity, flexible and convenient to use, and are widely used in construction sites.

[0003] Currently, most trolleys do not have a power-assisted device, so loaded trolleys are not suitable for occasions with stairs. A few electric-driven power-assisted trolleys use a three-wheel combined star wheel to climb stairs. Since the wheel diameter of the star wheel is fixed, it is not very suitable for stairs of different heights.

[0004] Or, as disclosed in the patent with the publication number CN111422229A, a stair-climbing transport trolley uses a combination of a support rod and an elastic member as a lifting mechanism. However, for the lifting or lowering of the lifting mechanism during the use of this trolley, manual operation is still required, resulting in low efficiency and instability.

[0005] Therefore, a new technical solution is needed to solve the above problems. Summary of the Invention

[0006] Object of the Invention: The present invention provides an electric-assisted trolley to solve the problems of low efficiency of manually-operated stair-climbing trolleys and poor applicability of trolleys with star wheels to stairs of different heights in the prior art.

[0007] To achieve the above object, the electric-assisted trolley of the present invention can adopt the following technical solutions:

[0008] An electric assist trolley, comprising a frame, a handle located at the rear end of the frame; further comprising a guide rod extending forward from the front end of the frame, a lifting mechanism located below the frame, and wheels located on both sides of the lifting mechanism; the lifting mechanism includes a lifting beam fixed to the bottom of the frame, an electric push rod fixed to the bottom of the frame and located behind the lifting beam, brackets extending downward from both sides of the lifting beam, a lifting rotating shaft with both ends respectively hinged to the two brackets, a first upper fork rod hinged to one side of the bottom of the lifting rotating shaft, a second upper fork rod hinged to the other side of the bottom of the lifting rotating shaft, a first lower fork rod hinged to the lower end of the first upper fork rod, a second lower fork rod hinged to the lower end of the second upper fork rod, a lead screw mechanism, and a bottom rod hinged to the bottom ends of the first lower fork rod and the second lower fork rod; the wheels are respectively hinged to both sides of the bottom rod through wheel axles; the front end of the electric push rod is hinged to the lifting rotating shaft, and when the electric push rod contracts, the wheels swing backward; the lead screw mechanism includes a motor, a lead screw coaxially connected to the output shaft of the motor, a lead screw nut located on the lead screw, and a motor flange connected to the back of the motor; the hinged part of the first upper fork rod and the first lower fork rod is simultaneously hinged to the back of the motor flange; the hinged part of the second upper fork rod and the second lower fork rod is simultaneously hinged to the two outer sides of the lead screw nut; when the lead screw rotates, the lead screw nut moves on the lead screw. When the lead screw nut moves closer to the motor, the angle between the first upper fork rod and the second upper fork rod becomes smaller, and the distance between the lifting rotating shaft and the bottom rod becomes smaller; when the lead screw nut moves away from the motor, the angle between the first upper fork rod and the second upper fork rod becomes larger, and the distance between the lifting rotating shaft and the bottom rod becomes larger.

[0009] Further, there are two guide rods, and the two guide rods are parallel and located in front of the frame, and guide wheels are further provided at the front ends of the guide rods.

[0010] Further, sliding grooves extending forward and backward are respectively provided on both sides of the bottom of the frame, the guide rods are inserted into the sliding grooves, a plurality of fixing holes are provided on the guide rods from front to back, insertion holes and pins located in the insertion holes are provided on the sliding grooves, and any fixing hole on the guide rod and the insertion hole can be fixed through the pin.

[0011] Further, the lower ends of the first upper fork rod, the second upper fork rod, the first lower fork rod, and the second lower fork rod are all U-shaped fork arm structures.

[0012] Further, a baffle extending upward is further provided at the front end of the frame.

[0013] The present invention also provides an operation method for the above-mentioned electric assist trolley, which is characterized in that it includes the following steps:

[0014] S1: Before going up the stairs, the lifting mechanism is in a contracted state, that is, the distance between the lifting rotating shaft and the bottom rod becomes smaller, so that the trolley approaches the side of the first step of the stairs, and the extension length of the guide rod is adjusted so that the guide wheel abuts against the side of the second step;

[0015] S2: Start the motor in the lifting mechanism to drive the screw rod to rotate, increasing the distance between the lifting rotating shaft and the bottom rod to lift the vehicle frame; at this time, the guide wheel rises along the side of the second-level step;

[0016] S3: After the guide wheel rises to the surface of the third-level step, start the electric push rod to retract and push the vehicle frame forward, lifting the whole trolley to the second-level step;

[0017] S4: Start the lifting mechanism to contract, and at the same time, the electric push rod is pushed out to restore the lifting mechanism to the initial state of climbing stairs;

[0018] S5: Repeat the above process to realize the operation process of the trolley going up the stairs;

[0019] S6: When going down the stairs, the operator goes down the stairs with the opposite actions as above.

[0020] Beneficial effects: Compared with the prior art, the present invention is provided with a driving device of a motor screw rod mechanism, so that the lifting mechanism can automatically lift the vehicle frame, which can assist the operator to carry heavy loads on the trolley up and down the stairs, reduce the labor intensity and improve the handling efficiency. At the same time, it can be lifted to the corresponding height position according to the height of the stairs, and is applicable to stairs of different heights or irregular stepped terrains. Among them, the wheels are located at the bottom of the lifting mechanism, so the vehicle frame can directly rise and fall relative to the wheels, and the electric push rod can swing the wheels backward to adjust the wheel position. This structure does not require additional installation space for the wheels, simplifying the overall structure. Description of the Drawings

[0021] Figure 1 is a schematic diagram of the trolley on the ground in the embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of the whole trolley in the embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of the lifting mechanism of the trolley in the embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of the small wheel of the trolley against the side of the second-level step in the embodiment of the present invention;

[0025] Figure 5 is a schematic diagram of the lifting mechanism lifting the trolley so that the guide rod is at the upper surface of the second-level step in the embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of the electric push rod contracting and the lifting mechanism rising appropriately to move the trolley forward in the embodiment of the present invention;

[0027] Figure 7It is a schematic diagram of the lifting mechanism in the embodiment of the present invention retracted to the minimum size and the electric push rod pushed out, with the wheel located on the upper surface of the first - stage step;

[0028] Figure 8 It is a schematic diagram of pushing the trolley forward in the embodiment of the present invention, with the guide rod against the side of the third - stage step. Specific embodiments

[0029] Refer to Figure 1 、 2As shown in FIGS. 2 and 3, the present invention discloses an electric assist handcart, which includes a frame 204, a baffle 203 extending upward at the front end of the frame, a handle at the rear end of the frame 204, two guide rods 202 extending forward from the front end of the frame 204, a lifting mechanism 209 below the frame 204, and wheels 208 on both sides of the lifting mechanism. The lifting mechanism includes a lifting beam 20901 fixed to the bottom of the frame 204, an electric push rod 210 fixed to the bottom of the frame 204 and located behind the lifting beam 20901, brackets extending downward from both sides of the lifting beam 20901, a lifting rotating shaft 20903 with both ends hinged to the two brackets respectively, a first upper fork rod 20902 hinged to one side of the bottom of the lifting rotating shaft 20903, a second upper fork rod 20906 hinged to the other side of the bottom of the lifting rotating shaft 20903, a first lower fork rod 20907 hinged to the lower end of the first upper fork rod 20902, a second lower fork rod 20912 hinged to the lower end of the second upper fork rod 20906, a lead screw mechanism, and a bottom rod 20910 hinged to the bottom ends of the first lower fork rod 20907 and the second lower fork rod 20912. Guide wheels 201 may be provided at the front ends of the guide rods 202. Sliding grooves 207 extending forward and backward are respectively provided on both sides of the bottom of the frame 204, and the guide rods 202 are inserted into the sliding grooves 207. A plurality of fixing holes 205 are provided on the guide rods 202 from front to back, insertion holes 206 and pins (not labeled) located in the insertion holes are provided on the sliding grooves 207, and any fixing hole 205 on the guide rod can be fixed to the insertion hole 206 through a pin, so the extending length of the guide rod can be adjusted to adapt to steps of different lengths. The wheels 208 are respectively hinged to both sides of the bottom rod 20910 through wheel axles. Since the wheels 208 move when the handcart is manually pushed, there is no mechanism for actively driving the wheels 208. The front end of the electric push rod 210 is hinged to the lifting rotating shaft 20903 and the rear end is hinged to the bottom of the frame 204. A fixed hinge 20905 for hinging with the electric push rod 210 is provided at the middle position of the lifting rotating shaft 20903; a fixed hinge 211 for hinging with the electric push rod 210 is provided at the bottom of the frame 204. When the electric push rod 210 contracts, the wheels 208 swing backward. The lead screw mechanism includes a motor 20904, a lead screw 20908 coaxially connected to the output shaft of the motor, a lead screw nut 20911 located on the lead screw 20908, and a motor flange 20909 connected to the back of the motor. The hinged part between the first upper fork rod 20902 and the first lower fork rod 20907 is simultaneously hinged to the back of the motor flange 20909; the hinged part between the second upper fork rod 20906 and the second lower fork rod 20912 is simultaneously hinged to the two outer sides of the lead screw nut 20911. In this embodiment, the lower ends of the first upper fork rod 20902, the second upper fork rod 20906, the first lower fork rod 20907, and the second lower fork rod 20912 are all U-shaped fork arm structures to facilitate stable hinging at the hinge points. When the lead screw 20908 rotates, the lead screw nut 20911 moves on the lead screw 20908.When the lead screw nut 20911 approaches the motor 20904, the angle between the first upper fork rod 20902 and the second upper fork rod 20907 becomes smaller, and the distance between the lifting rotating shaft 20903 and the bottom rod 20910 becomes smaller. When the lead screw nut 20911 moves away from the motor 20904, the angle between the first upper fork rod 20902 and the second upper fork rod 20907 becomes larger, and the distance between the lifting rotating shaft 20903 and the bottom rod 20910 becomes larger.

[0030] The operation method of the above-mentioned electric assisted handcart includes the following steps:

[0031] S1: As Figure 4 shown, before going up the stairs, the lifting mechanism is in a contracted state, that is, the distance between the lifting rotating shaft and the bottom rod becomes smaller, so that the handcart approaches the side of the first step of the stairs, and the extension length of the guide rod is adjusted so that the guide wheel abuts against the side of the second step;

[0032] S2: As Figure 5 shown, start the motor in the lifting mechanism, drive the lead screw to rotate, so that the distance between the lifting rotating shaft and the bottom rod becomes larger and the vehicle frame is lifted; at this time, the guide wheel rises along the side of the second step;

[0033] S3: As Figure 6 shown, after the guide wheel rises to the surface of the third step, start the electric push rod to retract, push the vehicle frame forward, and lift the whole trolley to the second step;

[0034] S4: As Figure 7 shown, start the lifting mechanism to contract, and at the same time, the electric push rod is pushed out, and the lifting mechanism returns to the initial state of climbing the stairs;

[0035] S5: Repeat the above process to realize the operation process of the handcart going up the stairs;

[0036] S6: When going down the stairs, the operator goes down the stairs with the opposite actions as above.

[0037] There are many methods and ways to specifically implement this technical solution of the present invention. The above description is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by the prior art.

Claims

1. An electric-assisted trolley, comprising a frame and a handle located at the rear end of the frame; Characterized in that, It further includes a guide rod extending forward from the front end of the frame, a lifting mechanism located below the frame, and wheels located on both sides of the lifting mechanism; The lifting mechanism includes a lifting beam fixed to the bottom of the frame, an electric push rod fixed to the bottom of the frame and located behind the lifting beam, brackets extending downward from both sides of the lifting beam, a lifting rotating shaft with both ends respectively hinged to the two brackets, a first upper fork rod hinged to one side of the bottom of the lifting rotating shaft, a second upper fork rod hinged to the other side of the bottom of the lifting rotating shaft, a first lower fork rod hinged to the lower end of the first upper fork rod, a second lower fork rod hinged to the lower end of the second upper fork rod, a lead screw mechanism, and a bottom rod hinged to the bottom ends of the first lower fork rod and the second lower fork rod; the wheels are respectively hinged to both sides of the bottom rod through wheel axles; the front end of the electric push rod is hinged to the lifting rotating shaft, and the electric push rod contracts to swing the wheels backward; The lead screw mechanism includes a motor, a lead screw coaxially connected to the output shaft of the motor, a lead screw nut located on the lead screw, and a motor flange connected to the back of the motor; the hinged part between the first upper fork rod and the first lower fork rod is simultaneously hinged to the back of the motor flange; the hinged part between the second upper fork rod and the second lower fork rod is simultaneously hinged to the two outer sides of the lead screw nut; When the lead screw rotates, the lead screw nut moves on the lead screw. When the lead screw nut moves closer to the motor, the angle between the first upper fork rod and the second upper fork rod becomes smaller, and the distance between the lifting rotating shaft and the bottom rod becomes smaller; when the lead screw nut moves away from the motor, the angle between the first upper fork rod and the second upper fork rod becomes larger, and the distance between the lifting rotating shaft and the bottom rod becomes larger.

2. The electric-assisted trolley according to claim 1, Characterized in that: There are two guide rods, and the two guide rods are parallel and located in front of the frame, and guide wheels are further provided at the front ends of the guide rods.

3. The electric-assisted trolley according to claim 1 or 2, Characterized in that: Chutes extending forward and backward are respectively provided on both sides of the bottom of the frame, the guide rods are inserted into the chutes, a plurality of fixing holes are provided on the guide rods from front to back, insertion holes and pins located in the insertion holes are provided on the chutes, and any fixing hole on the guide rod and the insertion hole can be fixed by the pin.

4. The electric-assisted trolley according to claim 3, Characterized in that: The lower ends of the first upper fork rod, the second upper fork rod, the first lower fork rod, and the second lower fork rod are all U-shaped fork arm structures.

5. The electric-assisted trolley according to claim 1, Characterized in that: A baffle extending upward is further provided at the front end of the frame.

6. An operation method of the electric-assisted trolley according to any one of claims 1 to 5, Characterized in that, It includes the following steps: S1: Before going up the stairs, the lifting mechanism is in a contracted state, that is, the distance between the lifting rotating shaft and the bottom rod becomes smaller, so that the trolley is close to the side of the first step of the stairs, and the extension length of the guide rod is adjusted so that the guide wheel is tightly pressed against the side of the second step; S2: Start the motor in the lifting mechanism, drive the lead screw to rotate, so that the distance between the lifting rotating shaft and the bottom rod becomes larger to lift the frame; at this time, the guide wheel rises along the side of the second step; S3: After the guide wheel rises to the surface of the third step, start the electric push rod to retract, push the vehicle frame forward, and the whole trolley is lifted to the second step; S4: Start the lifting mechanism to contract, and at the same time, the electric push rod is pushed out to make the lifting mechanism return to the initial state of climbing stairs; S5: Repeat steps S1 to S4 to realize the operation process of the handcart going up the stairs; S6: When going down the stairs, the operator makes the handcart go down the stairs with the actions opposite to those in steps S1 to S4 above.

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