Battery-powered walk-behind greensmower
View Patent ↗A greensmower having a cutting reel and a traction member and an independent electric circuit and motor for driving each. A handle is attached to the reel for mower guidance by an operator in a walk-behind position. Separate electric controls are connected to each motor for separate speeds for each motor and thereby control the clip rate of the mowing. There are low battery power read-outs and automatic shutoffs. Provision is made for traction powering of the mower even when the reel motor is not operating because of low battery power. A lift-out battery pack is shiftably mounted on the mower for producing the desired force of the mower on the ground.
1. A reel mower assembly:
a frame;
a reel having a plurality of blades, the reel rotatably coupled to the frame;
an electric motor drivingly coupled to the reel, a first drive current being applied to the electric motor during a startup mode, the first drive current having a maximum, and a second drive current being applied to the electric motor following the startup mode, the second drive current being less than the first drive current; and
a drive circuit for the electric motor, the drive circuit including:
a current limiting subcircuit, the current limiting subcircuit applying the first drive current to the electric motor; and
a timing subcircuit connected in parallel with the current limiting subcircuit and the timing circuit applying the second drive current to the electric motor, wherein the timing subcircuit introduces a predetermined time delay during which only the first drive current from the current limiting subcircuit is applied to the electric motor and wherein the second drive current is applied to the electric motor via the timing subcircuit after the predetermined time delay.
2. The apparatus of claim 1 wherein the current limiting subcircuit further comprises a thermistor.
3. The apparatus of claim 2 wherein the thermistor is a negative coefficient thermistor.
4. The apparatus of claim 1 wherein the timing subcircuit comprises a voltage control subcircuit, the voltage control subcircuit establishing a reference voltage to activation of other subcircuits of the timing circuit.
5. The apparatus of claim 4 wherein the timing subcircuit further comprises a time delay element, the time delay element controlling a rate of increase of the reference voltage.
6. The apparatus of claim 1 wherein the timing subcircuit further comprises a first switch, the first switch controlling activation of a second switch, wherein activation of the second switch applies the second drive current to the electric motor.
7. The apparatus of claim 6 wherein the first switch comprises a power transistor.
8. The apparatus of claim 7 wherein the second switch comprises a relay.
9. The apparatus of claim 6 wherein the second switch comprises a relay.