Black Decker Inc.

W Roger Thomas

Craig D Webster

Vincent Carr

Melvin Temple

A braking system for a powered rotary tool of the type in which a shaft is rotated about an axis by a motor includes a first brake element mounted for rotation with the shaft; a second brake element which is restrained from rotation; a biasing member normally urging the first brake element in an axial direction into braking contact with the second brake element and a brake release subsystem, the brake release subsystem to release the braking contact between the first and second brake elements upon start-up of the motor. On start-up of the motor, the shaft is free to rotate through a small angle of rotation before initiating rotation of the first brake element. The release subsystem includes at lease one pair of co-operating ramp surfaces, one of the ramp surfaces being arranged for rotation with the shaft and the other of the ramp surfaces being arranged for rotation with the first brake element. The braking system of the present invention is particularly suitable for use on a rotary-blade lawn mower.

Braking system

A lawn mower of the type which collects grass cuttings includes a motor-driven blade rotatable about a sustantially vertical axis, at least one fan rotatable about the same axis, and a grass collecting system of the type in which grass collection is aided by suction from an airstream produced by the fan. It includes a closure which is selectively adjustable to at least two positions: one in which a grass collection aperture in a grass box is closed and a debris collection aperture in the grass box is open, and the other in which the grass collection aperture is open and the debris collection aperture is closed. A second embodiment includes a closure which is selectively adjustable to at least two positions: one in which both the grass collection aperture and the debris collection aperture are open, and the other in which only the grass collection aperture is open.

Lawn mower with means for selectively collecting grass and grass plus

A braking system for a rotary mower includes a brake element which is secured to an impeller and is urged by a spring normally into braking engagement with a fixed brake friction member. On start-up of a motor of the mower, rotation of the impeller causes axial movement of the brake element against the spring and out of braking engagement. Movement of the brake element may be assisted by mechanical means, for example by a multiple ball and ramp system or arrangement. In this embodiment, four equally spaced balls are normally located in ramped recesses formed in an upper face of an adaptor element, such that on start-up of the motor, the balls ramp up at least partially out of the recesses, and assist in urging a braking element and a friction element out of braking engagement with one another. This assist stops when the motor is turned off, the balls now moving back into their respective lowest positions in the recesses formed in the upper face of the adaptor element.

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Cleveland, United Kingdom

W Roger Thomas