IMPROVEMENTS IN MILLSTONE DRIVERS
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by George Mosely Murray at the Office
of the Commissioners of Patents on the 14th March 1879. A communication
from abroad by Patrick H. Childress, of Waynesborough, in the County of
Augusta, and State of Virginia, in the United States of America:..
GEORGE MOSLEY MURRAY, of 13, Gloucester Place, Hyde Park, in the County of
Middlesex, Esquire. "IMPROVEMENTS IN MILLSTONE DRIVERS." [A communication
from abroad by Patrick H. Childress, of Waynesborough, in the County of Augusta,
and State of Virginia, in the United States of America.]
This Invention relates to an improved self adjusting and equalizing millstone
driver, designed principally to cause the driver to bear equally at both ends
upon the runner so as to cause the same to be driven in balance and without
wabbling.
It sometimes happens from various causes that the millstone driver bears upon
the runner at one end only, and this causes the runner to wabble. Among the
efforts to prevent this is to construct the driver in the form of two levers pivoted
upon opposite sides of the spindle, and to connect the inner ends of the said levers
with the spindle by a forked coupling embracing the spindle.
These improvements consist, first, in arranging about the spindle and between
the spindle and the forks of the jointed driver a ring or collar which affords a
bearing for the inner ends or forks of the driver sections, and by allowing the said
inner ends to swivel about, the same secures an equal and more direct movement
between the sections of the driver, obviates lost motion, and yet does not require
the forks to touch the spindle.
The improvements consist, secondly, in pivoting the sections of the driver upon
the same bolts which secure the top plate to the bottom plate.
In the Drawing the square opening in both top plate Ħ and bottom plate K. is for
the mill spindle to pass through. The lower plate K rests upon the seat or shoulder
of the spindle while the spindle projects through it through the ring E, through the
upper plate H, and thence to the cockeye of the balance-rynd, where it forms the
point of suspension of the runners. That portion of the spindle passing through
the driver being square fits accurately in the plates K and H and causes them (the
plates) to rotate rigidly with the spindle. B, B, are the levers which constitute the
driver, the same being pivoted on the vertical bolts A, A, which secure the plates K
and H. The outer extremities of these two levers constitute the bearing points of
the driver, and enter recesses in the runner or balance-rynd to impart motion_to

page_text: the said runner. The inner ends of these levers are coupled for the compensating
movement in a peculiar manner. Each inner end of the said levers is formed in
the shape of a fork, the branch F of one lever upon one side, overlapping a corre-
sponding branch G of the other lever upon the same side, while upon the opposite
side the branch G of the first lever is overlapped by the branch F of the other lever.
These forks are of circular outline, and in the centre leave a circular space in which
is arranged a loose ring E through which the spindle projects. This embrace of the
ring by the forks constitutes a peculiar coupling for the inner ends of the levers,
which it will be seen cause the movement of the outer ends of the levers in the same
direction, or the general movement of the levers upon their pivots to be in reverse
direction, the levers having at all times only a limited motion, such as is permitted
by the loose connection of the forks.
Now in describing the operation of the device it will be seen, referring to Fig. 2,
that when the runner is revolving in the direction of and following the letters a, a¹,
the faces a, a¹, at the extremity of the jointed driver are the points which bear
against and actuate the stone. Now if from any cause one end of the driver a¹³ for
instance should not bear against the stone, then if the driver be rigid and inflexible
the runner would simply be driven by the face a, and the stone being actuated upon
one side of its centre would be thrown out of balance..
With this arrangement of jointed and flexible driver it will be seen that if the
driver bears only at a the driver will bend in the centre by the swivelling of the
forks about the ring E, and the opposite lever will be deflected upon its pivot bolt
in the reverse direction, and its outer end a¹ will be advanced as shown in dotted
lines so that it will be in bearing contact with the runner and cause the latter to be
driven upon both sides of its centre and by both ends of the driver, thus keeping
the stone in balance.