US 5,293,731 A · Lawn mower

Abstract

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.

Claims20

Dependent claims

A braking system for a lawn mower, comprising:

a motor drivingly connected to a rotatable shaft;
an air impeller mounted for rotation on and with said shaft and movable in an axial direction relative to the axis of said shaft;
a brake element mounted for rotation with the impeller;
a friction element which is connected to a housing of said lawn mower and restrained from rotation;
resilient means for urging the brake element in an axial direction into braking contact with the friction element;
a cutting blade mounted on said shaft for rotation therewith, the cutting blade being spaced axially along said shaft from said air impeller;
and
said air impeller being formed to produce an air flow upon rotation by said shaft, said air flow creating a force on said air impeller to move said air impeller axially in opposition to said resilient means to disengage said brake element from said friction element.

5 more elements

Dependencies are inferred from the claim text.

Lawn mower

Life of this patent

Lawn mower

Life of this patent

Abstract

Claims20