Fiskars has been granted a patent for an electric pole pruner with a spring returned cutting head. The pruner includes a drive unit with an electric motor and an epicyclic gear assembly to reduce rotation speed and increase torque. A string element is used to actuate the cutting head, and a locking arrangement allows for selective locking or release of the gear assembly. GlobalData’s report on Fiskars gives a 360-degree view of the company including its patenting strategy. Buy the report here.
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Electric pole pruner with adjustable cutting head and locking gear
A recently granted patent (Publication Number: US11723313B2) describes an electric pole pruner with several innovative features. The pole pruner includes a longitudinal pole with a cutting head at one end. The cutting head consists of a knife that can move from a starting position to a cutting position when actuated by a pulling force. A biasing member returns the knife to the starting position when the pulling force is no longer exerted.
The pole pruner also features a drive unit located at a distance from the cutting end of the pole. The drive unit includes an electric motor, a drum, and an epicyclic gear assembly. The gear assembly reduces rotation speed and increases torque transmitted from the electric motor to the drum. A string element is coupled to the drum and the cutting head, causing the cutting head to be actuated when the drum rotates and exerts a pulling force on the string element.
One notable aspect of the pole pruner is a locking arrangement that selectively locks or releases the ring gear of the epicyclic gear assembly. This locking arrangement enables or prevents rotation of the ring gear, allowing the gear assembly to convert rotation of the electric motor into rotation of the drum when the ring gear is locked, and vice versa when the ring gear is released. The locking arrangement includes a brake rotor and a brake caliper with brake pads that frictionally engage the brake rotor to lock the ring gear.
Other features of the electric pole pruner include a lever for actuating the brake caliper, an operating switch that powers the electric motor when the lever is actuated, and a power input that can be coupled with a battery unit. The epicyclic gear assembly may also include multiple gear trains to further reduce rotation speed and increase torque. The gear ratio of the assembly can range from 36:1 to 200:1.
Additionally, the pole pruner may have a telescopic structure, allowing the longitudinal pole to be extended and retracted. A limit switch is included to disengage and restore the electrical coupling between the power input and the electric motor. The limit switch is actuated by an engaging member on the string element when the cutting knife reaches its cutting position.
Overall, this granted patent showcases an electric pole pruner with various innovative features that improve its functionality and efficiency.