The present invention relates to a wheelbarrow, such as a single-wheeled transport trolley with manual push, and in particular to a wheelbarrow provided with an electric motor having an electric motor to assist in moving the wheelbarrow.
A wheelbarrow, such as a hand-pushed single-wheeled transport trolley, is well passable on narrow paths and is often used to transport materials, parts, harvest or fertilizer in workplaces, fields, orchards, mountains or forests. As the wheelbarrow needs to be pushed by hand, manipulating it on poorly maintained paths, meadows or steep slopes is difficult, so the scope of its use is limited. When manipulating the wheelbarrow, it is necessary to push or brake, maintain forward/backward balance and left/right balance. Transporting goods on rough terrain is therefore often difficult, especially for occasional users such as amateur workers maintaining courtyards, houses, gardens and amateur food growers. The need to use a wheelbarrow at a remote location often arises.
These generally known issues give rise to many attempts to develop a convincing product.
Patent WO1992007747A1 proposes a solution to the forward/backward weight balance, in which all drive elements and part of the load space are placed above the wheel axle.
EP0867353A2 proposes an intuitive solution to controlling including a movable handle.
The left/right weight balance is solved by placing the batteries in different positions of the frame.
US2002/0084119A1 solves the weight balance by integrating the motor into the wheelbarrow wheel and the battery under the container.
DE202012009715U1 solves the weight balance by integrating the motor and batteries into the wheelbarrow wheel.
Due to the need for an easy transport of wheelbarrows, wheelbarrows with folding handles are already available on the market.
The solutions proposed so far do not provide an intuitive use comparable to a non-motorized wheelbarrow.
Known solutions to motorised wheelbarrows use a sliding lever or switch to control the drive.
Known battery placement solutions position the battery in a way that the centre of gravity of the battery is above the neutral axis, which raises the total centre of gravity even further from the neutral axis.
The invention is based on the background described so far and aims to provide a single-wheel transport trolley with manual push, in which the auxiliary force of the electric motor acts effectively on the wheel to reduce the required force exerted by arms, while reducing battery power consumption and weight balance around the neutral axis is similar to that of a non-motorized wheelbarrow. The wheelbarrow should be intuitively manageable and easy to transport, and its stored energy and unoccupied volume should also be used for other purposes.
In order to achieve the above identified purpose, in accordance with a first aspect of the invention, a wheelbarrow with an electric drive is proposed, which comprises: a frame for a container; a wheel mounted in the middle of the lower part of the frame of the container; right and left handle supports extending backwards from two sides of the frame for the container; a left and right leg, which are an integral part of the frame; an electric motor mounted in said wheel, which drives or brakes the wheelbarrow only when necessary; two separate batteries mounted in a protective housing attached to said legs; two handles overlapping to a limited extent said pair of supports which are fixed with respect to said supports; a contactless sensor for detecting the position of a hand that is attached to one of said handle supports; a multi-axis acceleration sensor rigidly connected to said frame, buttons accessible by a finger while simultaneously holding said handles; and a control system for monitoring the operation of said electric motor based on motor controller information, detected values of sensors for detecting the position of the user's hand, wheelbarrow position, temperature sensors of each battery, and allowing a selection of different operating modes according to the sequence of pressing said button.
According to the construction of this first aspect, the pushing forces acting on the handles are detected via a small movement of the hands in the forward/backward direction. The hand position sensor transmits a signal to the wheelbarrow controller so that the motor can drive the wheelbarrow according to push forces and manual work can be reduced, so a fully loaded wheelbarrow can be pushed onto a rough or gravel surface. With an empty container or in a slightly filled state on a level ground, the energy consumption of the battery can be reduced by not activating the electric motor.
In addition, the wheelbarrow is pushed by lifting the handles and then the pushing force acts on the handles. Especially if the load is transported on rough terrain or a slope, the position of the frame of the container may become unstable. Loss of balance is often further caused by the push of the grip of the handle on one side. Thus, the hand displacement sensor can detect the push forces that need to be applied to the grip in order to apply the correct traction force to the wheel.
The position of compact separate batteries allows for an optimal compromise between left/right and forward/backward balance, greater stability and easier manipulation with the container fully loaded or empty. The choice of modern batteries allows for a suitable compact installation and ensures great autonomy of operation. The battery installation method provides user protection against possible explosion of the battery and at the same time protects the battery from mechanical damage. Placing the battery in the housing, which is an integral part of the legs of the support frame, allows adequate cooling of the batteries and preserves the space under the container for the attachment of other electrical devices.
The use of a suitably large wheel allows the use of standard winter-profile tyres for scooters, which ensures better grip of the drive wheel on slippery surfaces at an acceptable cost, while allowing significantly smoother driving compared to tractor-profile tyres, which is especially noticeable on smooth hard surfaces.
Short overall length of the wheelbarrow and flanges built into the legs of the support frame for attaching the transport support contribute to an easy transport of the wheelbarrow on a towing hitch of a passenger car.
The wheel 1 comprises a wheel rim and a built-in motor, and is attached via a shaft to a wheel support 14 via a preferably form-fit connection. On one side of the motor, there is a mounting position of the wheel, preferably a perforated flange 24 which is preferably rigidly attached to the motor cover. Preferably, the rim is adapted to tubeless tyres having dimensions 3.00-10.
The support frame 2 is preferably made of a steel tube, preferably of round cross-section.
The support legs 3 are preferably made of a curved steel L-profile and are preferably welded to the support frame 2.
The plastic handles 4 are preferably round in shape and preferably glued to the tube of the support frame 2.
The container 5 is preferably made of sheet steel and is preferably welded to the support frame 2 via supports 13 and 17.
The shield 6 of the hand movement sensor is preferably circular in shape and preferably welded to the support frame 2, preferably positioned on the underside.
The button 7 is—preferably via an intermediate flange—preferably welded to the support frame 2, preferably positioned so that its upper edge does not reach the upper point of the support frame 2 at this point in height.
The battery housing 8 is preferably made of sheet steel and is preferably welded to the supported legs 3. It is configured in a way to form, together with the battery housing cover 19, an enclosed space of such a size that it embraces the battery together with the surrounding damping element, which preferably at the same time provides good thermal conductivity.
The control unit housing 9 is preferably made of sheet steel and preferably encloses the power motor controller and the wheelbarrow controller in a watertight manner. The control unit housing 9 is preferably attached to the support 13 via cylindrical damping elements 16 by a screw connection.
The cooling part 10 of the power motor controller has free access to the environmental air so as to provide sufficient cooling.
The two mounting flanges 11 of the supporting legs 13 with a form-fit connection, preferably with a rectangular cut-out, allow for adequate rigidity of the connection with the support for connection to the towing hitch.
The protective tube 12 is preferably made of a curved steel tube and is preferably welded on one side to the battery housing 8 and on the other side to the support 13.
The support 13 is preferably made of sheet steel and is preferably welded to the support frame 2.
The wheel support 14 is preferably made of sheet steel and is preferably welded to the support frame 2.
The tyre 15 is preferably a winter tyre for scooters.
The elastic damping element 16 is preferably fastened by a screw connection to the control unit housing 9 and the support 13, and is dimensioned to prevent the transmission of shocks from the support frame 2 to the control unit housing 9.
The support 17 is preferably made of sheet steel and connects the rear part of the container 5 with the rear part of the support frame 2 preferably via a welded joint.
The support 18 is preferably made of a curved steel bar and connects the front part of the container 5 with the front part of the support frame 2 preferably via a welded joint.
The battery housing cover 19 is preferably made of sheet steel and is preferably fastened to the battery housing 8 with a screw connection.
The neutral axle 20 extends from the grip of the hand with the handle to the junction of the tyre with the ground.
The position of the centre 21 of gravity of the batteries, far below the neutral axis 20, makes it possible to compensate for the unfavourable location of the centre of gravity of the motor and the centre of gravity of the container above the neutral axis.
The goal of balancing the wheelbarrow left/right is to keep the centre 22 of gravity of the wheelbarrow as close to the neutral axis 20 as possible.
The thread pattern of the tyre includes a number of grooves 23 mimicking winter tyres.
The mounting position of the wheel Tallows the connection of various devices, preferably a flange of a towing winch.
The motor is preferably a brushless DC motor and preferably transmits torque directly to the wheel shaft. The motor controller is preferably a controller used to control electric scooters. The wheelbarrow controller is preferably based on a 32-bit microcontroller and preferably has a built-in voltage converter to supply power from a preferably 48 V battery. The wheelbarrow controller receives signals from the sensors and the motor controller. The hand position sensor detects the position of the user's hand and transmits information to the wheelbarrow controller. The hand position sensor is mounted in the shield 6 of the sensor via a damping element 16. The button 7 is preferably a push-button switch 7 and is connected via conductors, which are disposed preferably in a tube of a support frame, to the wheelbarrow controller. The wheelbarrow controller changes the operating mode and emergency stop preferably based on different sequences of button pushes. Based on the axial movement of the arm, the wheelbarrow controller calculates the pushing or pulling force of the arms on the handles. The wheelbarrow controller controls the motor controller preferably via a software-implemented PID control mode. The batteries are preferably formed of lithium cells and preferably have a built-in monitoring system. The batteries preferably include a temperature sensor and provide temperature-related information to the wheelbarrow controller. The accelerometer preferably transmits acceleration data in three directions to the wheelbarrow controller. The gyroscope preferably transmits data on rotation about three axes to the wheelbarrow controller.
Number | Date | Country | Kind |
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P 2020 0 0048 | Mar 2020 | SI | national |