Year: 1885

page_text: We MATTHEW PETTIGREW CAMPBELL of 13 Minerva Street Glasgow and JOHN
MAC CALLUM of 492 Saint Vincent Street Glasgow Engineers do hereby declare
the nature of our invention to be as follows:-
The object of our invention is to provide means of varying the angular position
of the teeth of worm wheels or toothed wheels intended to gear with screws of
varying or of different pitch of screw thread.
To that end we fit the cogs or teeth of toothed wheels to the wheel rim by
means of pins or bolts formed on the cogs or teeth and passed through the rim of
the wheel within which such pins or bolts are secured by screw nuts or cottars.
Each tooth is free to oscillate upon its securing pin or bolt as a pivot so that while
the pitch or actual distance from centre to centre of the teeth always remains the
same they adapt themselves by swivelling or their pivots to the inclination of the
thread of the screw or worm with which they gear when screws or worms of varying
pitch or of different pitches are arranged to gear with the toothed wheel. The
teeth may be fitted with their securing pins passing radially through the rim of
the wheel or with the pins passing through the side of the rim parallel or at an
inclination to the axis of the wheel.
The pins may pass through a row of holes arranged in a circle round the wheel
rim or two rows of staggered holes may be formed so that the alternate teeth will
be pivotted in the outer circle of holes and the others in the inner circle.
ค

page_text: We, MATTHEW PETTIGREW CAMPBELL of 13 Minerva Street, Glasgow and JOHN
MAC CALLUM of 492 St Vincent Street Glasgow, Engineers, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
The object of our invention is to provide means of varying the angular position
of the teeth of worm wheels or toothed wheels intended to gear with screws or
worms so that such wheels may be adapted to gear with screws or worms of
varying or of different pitch of screw thread.
As represented in sectional side elevation and in front elevation in figures 1
and 2 of the accompanying drawings, we fit the cogs or teeth a, of a toothed
wheel to the wheel rim A, by means of bolts or pins a³, formed on the cogs
or teeth and passed through the rim of the wheel within which such pins or
bolts are secured, screw nuts b, cottars or similar devices being employed to
retain the pins of the teeth in the rim. Each tooth a is free to oscillate
upon its carrying or retaining pin a¹ as a pivot so that while the pitch or
actual distance from centre to centre of the teeth remains constant the teeth
adapt themselves, by swivelling on their pivots, to the inclination of the thread of
the screw or worm (as C) with which they gear when screws or worms of varying
pitch or different screws having unequal pitch are arranged to gear with the
toothed wheel. The swivelling teeth are by preference enlarged or formed with
shoulders near their roots bearing against each other, as shown, so as to distribute
the strain throughout the series of cogs or teeth.
The invention though only represented as applied to the bevel form of worm
wheel is equally applicable to other forms, the teeth being fitted with their securing
pins passing radially through the rim of the wheel or through the side of the rim
parallel or at an inclination to the axis of the wheel as circumstances may require.
The pins may be passed through a row of holes arranged in a circle round the
wheel rim, or two rows of staggered holes may he formed in the rim so that the
alternate teeth may be pivotted in the outer circle of holes and the others in
the inner circle.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
A toothed wheel having its cogs or teeth so centred in the rim as to permit of a
swivelling movement of the teeth substantially as and for the purpose set forth.
Dated this Treants third day of Tn 1000