GB2436511A

GB2436511A - Coil spring actuated lawn aerator

Info

Publication number: GB2436511A
Application number: GB0606254A
Authority: GB
Inventors: Miles Roland William Bozeat
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-03-29
Filing date: 2006-03-29
Publication date: 2007-10-03
Also published as: GB0606254D0; WO2007110652A3; WO2007110652A2

Abstract

A lawn aerator comprising pivoting tines 2 which are actuated by coiled torsion bar springs 1, tine holder pivots 3 being situated between the tines and the springs. The tine holder pivots are combined with cam followers 4 to form head units. The cam followers are acted upon by cams 8 attached to a rotating drive wheel 9, which movement compresses the springs and lifts the tine out of the ground. Several of the aerator units may be combined in one machine.

Description

IMPROVED COIL SPRING ACTUATED LAWN AERATOR

Lawn aerators are well known devices used in the maintenance of lawns and grassed areas.

Previously revealed lawn aerators and cultivators that utilise the release of potential energy from a spring to plunge the tines into the ground have exerted energy indirectly from the tines by applying forces to an associated actuating arm. The actions of the cams that raise the tines, compress the springs and withdraw the tines similarly have acted indirectly from the tines and springs. All of these indirect applications of force minimise the potential mechanical advantage consequently the actuating arms are necessarily of a more complex and substantial design and section [to resist the bending moments applied] than if they were acting directly, the springs have to be more powerful than if they acted directly upon the tine and the cams and followers need to be more substantial, and have more force applied to them, than if they were to operate in intimate proximity to the tine and spring. AU of the afore mentioned mechanical disadvantages mitigate against mechanical efficiency and simplicity.

The current invention discloses an improved coiled torsion bar spring actuated lawn aerator in which the relative dispositions of the actuating coiled torsion bar springs, cams, cam followers and pivoting tines are such as to maximise the mechanical advantage. The actuating coiled torsion bar springs act directly upon the centre lines of the pivoting tines through moulded nylon head units which head units combine and group as closely as is practical a cam follower and tine holder leaving the arms upon which the head units are mounted to act as unstressed radial locating devices for the springs, tine holders and tines. The lifting cams of the combined double sided offset cam / drive wheel unit act directly beneath the actuating coiled torsion bar springs and immediately along side the pivoting tines which pivoting tines except when in or being drawn from the lawn are maintained in an essentially vertical position against the cam/driveshaft in preparation for successive plungings into the lawn. The machine automatically produces a regular pattern of holes in the lawn all in a relatively lightweight, inexpensive, compact, self propelled and hand portable machine.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figures 1 / 2 / 3 / 4 are schematic representations of the invention.

For clarity in none of the Figures above are the power source or the chassis of the machine carrying manifestations of the invention shown.

Figure 5 is a cutaway general arrangement perspective of a machine embodying a second manifestation of the invention.

Referring to the drawings an improved coil spring actuated lawn aerator comprises actuating coiled torsion bar springs [1] which actuating coiled torsion bar springs [1] act directly onto pivoting tines [21 through tine holder pivots [3] which tine holder pivots [3] are located directly above the pivoting tines [2] and directly below the actuating coiled torsion bar springs [1] the leading edges of cam followers [4] are located at the nearest possible position to tine holder pivots [3] and directly beneath the actuating coiled torsion bar springs [1] tine holder pivots [3] are integrally combined with cam followers [4] to form head units [5] which head units [5] are mounted on radial locating arms [6] at a distance from the radial locating arm pivot bar [7] actuating coiled torsion bar springs [I] are compressed by the rotary and upward action of cams [8] which cams [8] are integral with and disposed around both sides of drive wheel [9] acting upon the cam followers [4] concurrently pivoting tines [2] are drawn out of the lawn [10] whereupon pivoting tines [2] are returned and held against drive shaft [11] once drawn from the lawn [101 by the action of springs [12] acting between pivoting tines [2] and radial locating arms [6] [Figs I / 2 / 3 / 4] Multiple manifestations of the invention may be ganged together in a machine each manifestation operating sequentially with the next so to produce a higher aerating capacity per machine [Fig 5]

N

Claims

CLAIMS

An improved coil spring actuated lawn aerator which comprises actuating coiled torsion bar springs [1] which actuating coiled torsion bar springs [1] act directly onto pivoting tines [2] through tine holder pivots [3] which tine holder pivots [3] are located directly above the pivoting tines [2] and directly below the actuating coiled torsion bar springs [I] the leading edges of cam followers [4] are located at the nearest possible position to tine holder pivots [3] and directly beneath the actuating coiled torsion bar springs [1] actuating coiled torsion bar springs [1] are compressed by the rotary and upward action of cams [8] which cams [8] are integral with and disposed around both sides of drive wheel [9] acting upon the cam followers [4] concurrently pivoting tines [2] are drawn out of the lawn [10] whereupon pivoting tines [2] are returned and held against drive shaft [II] once drawn from the lawn [10] by the action of springs [12] acting between pivoting tines [2] and radial locating arms [6]
2. An improved coiled torsion bar spring actuated lawn aerator as in claim 1 where the tine holder pivots [2] and cam followers [4] are combined into head units [2]
3. An improved coiled torsion bar spring actuated lawn aerator as claimed in claims I and 2 above wherein multiple manifestations of the invention are ganged together in a machine.