IMPROVEMENTS IN APPARATUS FOR PREVENTING THE DELETERIOUS EFFECTS OF BACK LASH'IN DRIVING MILL- STONES
Year: 1869

page_text: LETTERS PATENT to John Lomax, of Hulme, in the County of
Lancaster, for the Invention of "IMPROVEMENTS IN APPARATUS FOR
PREVENTING THE DELETERIOUS EFFECTS OF BACK LASH'IN DRIVING MILL-
STONES."
Sealed the 26th October 1869, and dated the 26th June 1869.
PROVISIONAL SPECIFICATION left by the said John Lomax at the
Office of the Commissioners of Patents, with his Petition, on the
26th June 1869.
I, JOHN LOMAX, of Hulme, in the County of Lancaster, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN APPARATUS
POR PREVENTING THE DELETERIOUS EFFECTS OF BACK LASH'IN DRIVING MILL-
STONES," to be as follows:-
It is well known to millers that in driving millstones with a single
cylinder steam engine the variation of speed of the crank shaft of the
engine during the different portions of the stroke of the piston (whilst.
the stones have a tendency to run constantly at one uniform speed)

page_text: causes an amount of "back lash" at every stroke of the engine against
the non-driving sides of the teeth of the wheel and pinion which com-
municates motion to the running stone, which "back lash" causes a
large amount of unnecessary vibration and wear and tear of the whole of
the working parts, and frequently occasions a "break down" by fracturing
the "millrynd" or the teeth of the wheel. In order to remedy this
defect instead of keying the pinion fast upon the millstone spindle as
hitherto practised I bore the eye of the wheel in a conical form, and
support it upon a corresponding cone, which I key fast or otherwise
attach firmly to the millstone spindle. Above the wheel I also fix on
the said spindle two radial arms or drivers which press against two
springs attached to the arms of the pinion. The effect of these springs
is always to keep the driving surfaces or sides of the teeth of the wheels
in contact, the cone allowing of a certain amount of movement of the
boss of the pinion on the spindle whenever there is a tendency of the
stone to overrun the engine, and thus the effects of the "back lash
entirely obvinted, and the whole gearing runs perfectly steady without
vibration.
"
It will be evident that if preferred the drivers may be attached to the
pinion and the springs to the millstone spindle, or that the springs may
he interposed between the pinion and the spindle in any other convenient.
manner so as to produce the desired effect.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Lomax in the Great Seal Patent Office on the
24th December 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
LOMAX, of Hulme, in the County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of June, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Lomax, Her special license that
1, the said John Lomax, my executors, administrators, and assigns, or
such others as I, the said John Lomax, my executors, administrators,

page_text: and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR PREVENTING
THE DELETERIOUS EFFECTS OF BACK LASH' IN DRIVING MILLSTONES," upon
the condition (amongst others) that I, the said John Lomax, my exe-
cutors or administrators, by an instrument in writing under my, or their,
or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said John Lomax, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement and accompanying Drawings (that is to say) :—
It is well known to millers that in driving millstones with a single
cylinder steam engine the variation of speed of the crank shaft of the
engine during the different portions of the stroke of the piston (whilst
the stones have a tendency to run constantly at one uniform speed)
causes an amount of "back lash" at every stroke of the engine against
the non-driving sides of the teeth of the wheel and pinion which com-
municate motion to the running stone, which "back lash" causes a
large amount of unnecessary vibration and wear and tear of the whole of
the working parts, and frequently occasions a "break down" by fracturing
the millrynd" or the teeth of the wheel. In order to remedy this
defect, instead of keying the pinion fast upon the millstone spindle as
hitherto practised, I bore the eye of the wheel in a conical form, and
support it upon, a corresponding cone, which I key fast or otherwise
attach firmly to the millstone spindle. Above the wheel I also fix on
the said spindle two radial arms or drivers, against which press two
springs attached to the arms of the pinion. The effect of these springs
is always to keep the driving surfaces or sides of the teeth of the wheels
in contact, the cone allowing of a certain amount of movement of the
boss of the pinion on the spindle whenever there is a tendency of the
stone to overrun the engine, and thus the effects of the "back lash" are

page_text: entirely obviated, and the whore gearing runs perfectly steady wICHONG
vibration.
It will be evident that if preferred the drivers may be attached to the
pinion and the springs to the millstone spindle, or that the springs may
he interposed between the pinion and the spindle in any other convenient
manner so as to produce the desired effect.
Such being the nature and object of my said Invention for "Improve-
ments in Apparatus for Preventing the Deleterious Effects of Back.
Lash in Driving Millstones," I will now proceed to describe more in
detail the manner in which the same is to be or may be performed and
carried into practical effect, and in order that the same may be clearly
understood have annexed herennto a Sheet of Drawings illustrative
thereof, and have marked the same with figures and letters of reference
corresponding with those in the following explanation thereof.
Fig. 1 in the annexed Drawing represents a front view shown partly
in section, and Fig. 2 a side view of the driving gear of a running mill-
stone with my improved apparatus shown as attached thereto.
a, a, is the framing; b, b, the millstone spindle; and c, c, the bevil
pinion for driving the same. It will be seen that the eye of this wheel
is bored in a conical form, and fits on a corresponding cone d, d, which
is keyed or pinned fast to the millstone spindle, and turns with it.
Above the wheel two radial arms or drivers e, e, are fixed to the spindle,
and also turn therewith, and these arms press against two plate
springs attached to the arms of the driving pinion, a buffer of india-
rubber or other suitable substance g, g, being (by preference) interposed
as seen at Fig. 2. The effect of the springs, as before described, is
always to keep the driving surfaces or sides of the teeth of the pinion c, c,
in contact with those of the wheel that drives it (represented by the
dotted circle in Fig. 1), the cone d, d, allowing of a certain amount of
movement of the boss of the pinion c, c, on the spindle b, b, whenever
there is a tendency of the stone to overrun the engine.
Having now described the nature and object of my said Invention,
together with the manner in which the same is to be or may be per-
formed or carried into practical effect, I wish it to be understood that I
claim as my Invention the use or employment for such purpose of the
cone d, d, arms e, e, and springs, in the manner above described and
shown on the Drawings annexed, or any mere modification or imitation

page_text: thereof, constructed and operating in substantially the same or a similar
manner.
In witness whereof, I, the said John Lomax, have hereunto set my
hand and seal, this Twenty-second day of December, in the year
of our Lord One thousand eight hundred and sixty-nine.
Witnessed by
GEORGE DAVIES, C.E.,
Office for Patents,
Manchester.
JOHN LOMAX. (L.S.)