OutdoorKing Repair Forum Forums The History Forum Component Histories GREENFIELD - Theo Reinhold Patents 1980s

Greenfield Products� founder Theo Reinhold was a prolific inventor and
patentee for over fifty years. His contribution to the Australian garden
tractor industry is significant and probably unsurpassed for any one
single person.

For the record, this topic makes available his significant patents from the
1980s. These will be covered by design theme � rather than by chronological
date. I have made available the AUSPAT patent documents, sometimes edited for
better readability.



TO BE CONTINUED ...

PATENT 78865 of 1981
Theo appears to have started the new decade with a new mower design.
The main patented features were the cutter deck and engagement mechanism.



This would become the production Greenfield 5XL & 8XL ride-on.


SOURCE: Geoff Nowak Flikr Photostream.

PATENT 89142 of 1982
This patent, titled �Improvements to Lawnmowers�, specifically dealt
with the blade drive control assembly. My reading of this patent is that
the new design made a more geometrically compliant unit � to overcome a
potentially dangerous situation: the inadvertent and spontaneous engaging
of drive to the cutters when the deck was set at low-cut settings.

PREVIOUS DESIGN as seen in FIG 1 & 2:-


THIS INVENTION as seen in FIG 3 & 4:-

THEO REINHOLD PATENTS 1960s & 1970s



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PATENT 58701 of 1986
This patent involved the Greenfield Clutch Assembly, arguably the best
mechanical, friction clutch design used anywhere in the world, which could
deliver variable speed, forward-reverse, to ride-on lawn tractors. This is
a credit to the genius of Theo Reinhold.

This patent covers an improvement on the design in terms of cost of
manufacture, assembly time, and quietness of operation: It was �more
reliable and efficient in use�.

The patent is in typical �lawyer�s speak�. The accompanying drawings go to
a more clear explanation, and I feel these improvements will be only
understood by the �Greenies� with good knowledge of the Greenfield design.

Here is a diagrammatic view of the drive mechanism:-


FIG 2 is an exploded view of FIG 1:-


FIG 3 is a top elevational view of the clutch assembly.
FIG 4 is an exploded sectional view
FIG 5 is an elevational view

PATENT 72239 of 1987
This short and simple patent is covered under the generic title
�Improvements to Mowers�. Specifically, it is a simple invention for
improving cutter decks when encountering long grass. In essence, it
covers a simple removable guard to convert a domestic ride-on cutter
deck to a slasher type. The patent also covers the attaching method �
enabling the guard�s quick removal.

PATENT 81939 of 1987
These two patents draw attention to the ride-on grass catcher.
These were popular accessories for many imported ride-ons, but much less
so for AUS made ride-ons. The main reason was that the first Australian
made designs were awkward and heavy, expensive and sometimes awkward to
use.

I think these patents reflect changes in catcher designs that were
occurring overseas, particularly in the USA, the leaders in the design of
ride-on garden tractors. Catchers had to be lighter and therefore made out
of materials like plastic and fabrics. They also had to be more easily
attached, removed, and emptied.

The catcher housing (discharge chute) would be supported by the cutter deck,
but the main weight of the catcher would be carried by a suspension system
attached to the mower frame. The catcher, itself, could be side or rear
mounted.



PATENT 10154 of 1988
This later patent shows Theo�s mind was continuing to develop the ride-on
catcher design. This second patent is a more mature rendition of his thinking
in the first patent (above).

This patent reiterates the desired goal of the previous patent but
focuses on an easier emptying system. It also established better terminology
for the respective components. For example, the �delivery chute assembly�
now has a �transfer chute� and a �transition chute� to the �grass container�.
The main claim seems to centre on the quick-release of grass for emptying.

For me, there is a clear similarity between the development of the grass
catcher for pedestrian rotary lawnmowers and their ride-on equivalents.
Catchers had to be made cheaper, lighter and more user-friendly.

PATENT 22191 of 1988
The second patent from 1988 concerned a parking brake.
This design was not for braking a moving machine but holding the
machines on inclines when parked.

PATENT 30828 of 1989
This patent returns to the design of the Greenfield clutch assembly,
and in particular, a refinement to the �Clutch Fork Supporting Bracket�.

The new design was intended to overcome a potential issue in the previous design:
A difficulty associated with such drives is that the power
transmission from the clutches to the rear wheels is
dependent upon the engagement force between the
clutch plate and the associated pulley wheel. This
engagement force which is effected through a clutch actuator
may be insufficient in certain instances to enable the full
available power to be transmitted.

However, a more careful reading of this patent seems to indicate this
new design was more an expression of the need for a simpler design for
production purposes (automatic welding).

PATENT 34531 of 1989 - Part One
This patent is titled �Improvements to Lawnmowers�, and it deals with three
separate components to walk behind � domestic - rotary lawnmowers.

The first idea is a Back-To-The-Future re-design of one of the main features
of early rotary lawnmowers � the ability to cut close to edges
[see Figures 1, 2 & 3].

Modern high arch designs have resulted in offset pairs of wheels � the
�outer side� enabling a clear flow of the grass chute to the catcher; the
'inner side� for edging (getting as close as possible to the edge).

This patent address the reality of thick aluminium bases [for strength]
preventing a closer gap between blade tip and lawn edge. Theo�s solution,
a thin cover plate [I guess of plastic or steel] over a base cut-out on
the inner side of the lawnmower.

The second idea concerned handle mounting [Figure 4]. A simple arrangement
that I wish had been adopted on those cheap entry-level steel bases we see
today! The idea is that the base itself (via a cast or pressed recess)
locates and takes the pivotal movement of side-mounted handle bars.



The third idea concerned the blade holder. It is of �square cross-sectional
configuration� and the holder is dished. This is one for the purists, and
I see some advantage in the design. It certainly makes tool access to the
blade bolts easier. Probably better for manufacture too.




TO BE CONTINUED ...

PATENT 34531 of 1989 - Part Two
The patent for walk-behind mowers is significant - in that these subtle
but clever patents were incorporated and remain to this day (2017).
The Greenfield walk-behinds are, arguably, the best residential
lawnmowers made in this country ...





http://greenfield.com.au/mower/walk-behind/

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