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US 4,344,273 AGranted
Lawn scarifier and rake
AssigneeBlack & Decker Inc.
InventorsAlan V. Jobling, David J. Crisp
Life of this patent
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AssigneeBlack & Decker Inc.
InventorsAlan V. Jobling, David J. Crisp
Estimating the term…
A turf scarifier and raker includes a housing with an elongated upright handle and having suitably positioned wheels designed to permit traversing movements over turf while the operator is in a standing position. The housing has an electric motor positioned in essentially the same plane as a tine assembly driven by the electric motor. The tine assembly has a plurality of tines which extend through an opening at the bottom of the housing. The tines result from a plurality of torsion coil springs having radially extending active ends that are serially threaded on rods arcuately and radially located about a central axle of the tine assembly. The active ends come into contact with the turf when the device is operated. At the same time, the other ends of the springs are inhibited from turning torque, preferably by lying in abutment against the central axle. The tines are arranged along helical paths about the central axle to contribute to a more constant torque resistance to the rotation of the tine assembly by causing the tines along each helical path to successively engage the lawn.
A lawn device, comprising:
A lawn scarifier and raker device, comprising:
A turf scarifier and raker device, comprising:
In a lawn scarifier and rake, the combination of a carriage and means for longitudinally moving the carriage across the lawn, a shaft rotatably journaled in the carriage along an axis transverse to the longitudinal movement of the carriage, a plurality of respective rods spaced radially from the shaft, means for rotating the rods in unison with the shaft and about the axis of the shaft as an integral assembly, each of the rods being disposed along a helical angle with respect to the shaft, and a plurality of coil springs serially threaded axially on each rod and carried thereby, each of the springs having a pair of ends including an active end and a passive end respectively projecting radially of the rod, the active end being formed as a tine for engaging the lawn during operation, and the passive end being reactively deflected against the shaft substantially in tangential abutment thereto when stress is applied to the tine during operation, whereby the helical angle of the rods contributes to a more constant torque resistance to the rotation of said assembly by causing the tines along each rod to successively engage the lawn.
In a lawn scarifier and rake, the combination of a carriage and means for longitudinally moving the carriage across the lawn, a shaft rotatably journaled in the carriage along an axis transverse to the longitudinal movement of the carriage, a motor on the carriage for driving the shaft, three rods each spaced radially of the shaft and substantially equidistant to each other, means for rotating the rods in unison with the shaft and about the axis of the shaft as an integral assembly, each of the rods passing helically through an angle of substantially 120 degrees over its length, and a plurality of coil springs mounted on each rod in substantial axial abutting relationship to each other, and each of the springs having a radially-projecting end portion formed as a tine for engaging the lawn during operation, the first tine in any one row being in substantially the same axial plane as the last tine in the prededing row, thus preceding a substantially constant torque resistance to the rotation of said assembly by causing the tines along each individual rod to make contact with the lawn in succession.
A lawn device, comprising:
Dependencies are inferred from the claim text.