Referring to
The grass mower 1 includes an operation division 3 accommodating a disc-shaped rotary cutter 9, a motor division 6 accommodating a motor and its ancillary, and a power-source division 8 accommodating a battery 7. The operating lever is divided into a front operating lever (hereinafter, “front lever”) 10 and a rear operating lever (hereinafter, “rear lever”) 11.
The front lever 10, as shown in
As best shown in
In
The motor division 6 of this first version is exclusively composed of a motor which includes a shell 22 housing a rotor 25 and a stator 26 fixed directly on the inside wall of the shell 22. The rotor 25 is rotatively arranged in the central space of the shell 22, and is provided with a recessed engager 28 corresponding to the projecting engager 23 of the input side of the power-transmission shaft 12.
The output shaft of the rotor 25 projects through the motor division 6 toward the input shaft of the front lever 12. The shell 22 is provided with a flange 30 having threads 31 on and along its periphery. Herein, the motor 6 is selectively a brushless motor.
In this version the motor division 6 and the front lever 10 are coupled by means of the nut 21 and the threads 31, thereby joining the flanges 20 and 30 together. In this way the motor division 6 and the front lever 10 are integrally connected into a single driving unit.
In this case, the connection between the projecting engager 23 and the recessed engager 28 secures the connection of the rotor 25 and the power-transmission shaft 12 only in a rotational direction, but not in an axial direction, which means that the power-transmission shaft 12 and the rotor 25 can be separated in the axial direction.
As a result, by unfastening the nut 21 out of the threads 31, and separating the rotor 25 from the power-transmission shaft 12, the motor division 6 and the front lever 10 are readily disassembled.
By taking the reverse procedure; that is, by fastening the nut 21 to the threads 31 and connecting the rotor 25 to the power-transmission shaft 12, the assembly is instantly achieved.
As is evident from the description mentioned above, the grass mower can be readily subjected to regular maintenance, such as oiling, replacement of parts and cleaning, as described below.
Referring to
The shell 22 is provided with a two-tine engager 33 having a bore 35 passing through the two tines, and the rear lever 11 is provided with a tongue 36 projecting toward the two-tine engager 33, the tongue 36 having a bore 37 passing through the tongue 36. The tongue 36 is inserted into between the tines 33, and a screw 38 is inserted through the bores 35 and 37.
In this version the motor division 6 and the rear lever 11 can be connected as tightly as desired with the screw 38.
In addition, the rear lever 11 can be connected to the motor division 6 at a desired angle by fastening the screw 38 as illustrated in
Referring to
The rear lever 11 is connected to a power-source division 8 which is installed in the same manner as the motor division 6 and the front lever 10 are connected. Referring to
The power-source division 8 includes a casing 52 having threads 55 on and along its periphery, the threads 55 being adapted to mesh with the nut 51 so as to couple the power-source division 8 with the rear lever 11.
The power-source division 8 is provided with pins 56 on its end face, and the rear lever 11 is provided with a socket 57. When the pins 56 are secured in the socket 57, the power-source division 8 and the rear lever 11 are electrically connected.
This version of grass mower has an advantage that the rear lever 11 can be readily disconnected from the power-source division 8 merely by disengaging the pins 56 from the socket 57.
The rear lever 11 houses an electrical conductor 58 in the form of a cable, which connects the socket 57 to the controller 41. The controller 41 has another cable 59 electrically connected, and the cable 59 is electrically connected to the motor division 6.
According to this version of grass mower, the power-source division 8 can be readily dismounted, and replaced with another power-source of different capacity and voltage where necessary. Owing to this feature, the level of output power can be adjusted to the working conditions, such as those of the cutting grass.
Preferably, the controller 41 is provided with a voltage detector (not shown) for monitoring variations in the voltage input from the power-source division. The controlling mode is varied in accordance with the voltage monitored by the voltage detector, thereby ensuring the constant supply of adequate power. For example, suppose that the power-source division 8 is a built-in lithium battery having two stages of circuits in series, the power-supply voltage will be about 6 to 9 volts.
If the power-source division 8 is a built-in lithium battery having four stages of circuits in series, the power-supply voltage will be about 12 to 18 volts. If the power-source division 8 is a built-in nickel-hydrogen battery having ten stages of circuits in series, the power-supply voltage will be about 12 volts. If the power-source division 8 is a built-in nickel-hydrogen battery having twenty stages of circuits in series, the power-supply voltage will be about 24 volts. The controller 41 monitors the voltage varying with the capacity of the battery, thereby supplying a power of adequate capacity to the motor division 6. When the battery voltage is high, a higher voltage is applied to the motor division 6, but the voltage is not proportional to the voltage at the power-supply division 8.
The first version of grass mower is operated as follows:
The operation can be conducted in a light-load mode, a heavy-load mode, an energy-saving mode, and a special mode. The light-load mode is suitable for cutting soft grass such as lawn at a relatively low voltage applied to the motor division 6, where the rotary cutter can slowly rotate at a current with a relatively low upper limit.
The heavy-load mode is suitable for cutting grass whose stalks are stiff at a high voltage applied to the motor division 6, where the rotary cutter can speedily rotate at a current with the high upper limit. In this case, the power-source division 8 is replaced with an adequate power-source
The energy-saving mode is a mode in which the current is intermittently supplied to the motor-division 6; more particularly, the current is supplied at a predetermined cycle, or in other words, a pulsating voltage is applied to the motor division 6. In this mode, the motor division 6 rotates at intervals, but the rotary cutter 9 functions as a balance wheel and can rotate at a constant speed under its own momentum. In this mode the load is constantly monitored; more particularly, the current supplied to the motor division 6 is constantly measured. The variations in the load are ascertained indirectly through the measured current values.
When the load increases, the power-supplying time is prolonged per hour; for example, the pulse width is increased without changing the frequency, or alternatively, the pulse intervals are shortened without changing the pulse width, thereby avoiding energy waste. Another advantage is that the rotary cutter can be instantly stopped if it is prevented from rotation by being caught by an unexpected obstacle, thereby keeping the motor safe from being damaged.
This version of grass mower can reduce the current supplying time per unit hour when an overload occurs in the grass mower. For example, the rotary cutter is stopped from rotation by being caught by a tree branch. In this way, the motor can be protected against being burnt out.
The special mode is selected when a cutter other than a rotary cutter and/or an attachment is to be used. The rotations per minute (r.p.m.) is predetermined in accordance with the intended use. For example, when a nylon cord cutter is used, the r.p.m. is set so as to achieve a high speed at which the operation division is performed. In this version of grass mower a clipper can be employed when small grass is cut or trimmed, where it is required to rotate the motor at a slow speed.
The following description is about how to deal with the front lever when the cutter is replaced with another type:
Referring to
In this version the shell 22 of the motor division 6 is joined to the rear lever 11 by means of the screw 38, which constitutes a clevis type structure. The mere handling of the screw 38 can connect and disconnect the shell 22 and the rear lever 11, thereby allowing the relative angle between the motor division 6 and the rear lever 11 to vary readily as desired. Therefore, it is easy to bend the rear lever 11 when necessary. Since the motor division 6, the most heavy part, is positioned in the middle of the entire body, the operator can easily raise the machine up and will be kept safe from fatigue even if the grass cutting lasts long.
The rotary cutter can be replaced with a nylon cord cutter. As shown in
The clipper-type cutter is generally heavier than the ordinary rotary cutter, but it can be well balanced with the heavy motor division 6 placed in the middle of the entire body. Therefore, no difficulty will be felt during the operation. The example illustrated in
In the embodiments described above the power-source division 8 can be readily replaced in accordance with the purposes, for which the capacity and voltage variously vary. Furthermore, if necessary, one or two more motor divisions can be added.
In the embodiments described above the rear lever can be bent for the motor-division. It is also possible that the rear lever can be more bent; for example, at its middle portion so as to ensure that the rearmost lever portion is arranged at an angle to the motor division.
Number | Date | Country | Kind |
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172535/2006 | Jun 2006 | JP | national |