AN IMPROVED MACHINE FOR CUTTING OR DRESSING MILLSTONES
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Olark at
the Office of the Commissioners of Patents, with his Petition, on
the 8th September 1869.-A communication from abroad by Jean
Bernard Lang and Rodolphe Mayor, of the Firm of Lang and
Company, of Geneva, Switzerland.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "AN IMPROVED MACHINE FOR CUTTING OR DRESSING MILLSTONES,"
to be as follows:-
This machine is substantially made up of the following four distinct
portions, viz.
Firstly. A suitable frame or stand.
Secondly. Certain arrangements for fixing the machine to the runner
or to the bed stone.
Thirdly. An apparatus for carrying the diamond tool, and which allows
of the latter taking any suitable direction for cutting the furrows or
grooves, or for dressing the stone.

page_text: Fourthly. A driving arrangement for causing the diamond tool to
rotate.
As to the first portion named, the frame is a skeleton stand of cast
iron or other suitable material with an upright cylindrical shaft attached
to it; this shaft may be made of tube iron for the purpose of giving it
the diameter suited to the proper working of the parts which it has
to guide, and at the same time leaving it as light as possible.
As to the second portion named, the machine is fixed on the top
stone or runner by means of three or more horizontal screws working in
brackets at the base of the frame; these screws butt or jam against the
inside of the eye of the runner. The machine is also fixed on the lower
or bed stone by means of three or more screws horizontally placed at the
bottom of the frame, and bearing against the millstone shaft. The
brackets which form nuts or female screws to receive the above hori-
zontal screws are so fitted in slots at the lower part of the stand or
frame that they may be shifted to any radial direction and screwed
tight in any desired position by means of nuts. Thus the machine may
be fixed on any millstone regardless of the diameter of the eye.
In respect of the third portion herein-before named, the apparatus
which carries the diamond tool in such manner as to allow of its being
directed in any line required is composed of the following parts :-
(a.) A horizontal slotted arm capable of turning about the cylindrical
axis or shaft of the frame, as herein-before described; this arm is steadied
on the said shaft by means of a hand screw; it may also be raised or
lowered by sliding on the frame shaft so as to regulate the initial position
of the tool-holding apparatus on the millstone.
(b.) A carriage or slide rest which works in the slot of the afore-
mentioned arm so as to be set nearer to or further from the centre of the
frame or of the millstone, or take any inclined position with respect
to the arm. The proper position of the slide rest having been fixed
upon it is securely bolted down. The slide rest also has a controlling
screw worked by a handle and acting either backwards or forwards on a
screw nut embracing it.
(c.) A vertical frame jointed at its upper portion to an axis or shaft
mounted on the movable screw nut last mentioned, the said frame being
capable of rocking or oscillating about the shaft.

page_text: (d.) One horizontal framing jointed or hinged at one point to the
lower portion of the above-mentioned vertical frame, and at the other
point to a table resting on the stone.
(e.) Another horizontal framing which is hinged on one side to the
table last referred to, whereas the other side supports the tool shaft.
This tool consists of two discs or washers keyed upon a horizontal shaft,
and encasing a black diamond. The tool shaft is mounted on screw
centre points by which the friction is regulated.
(f) An upright screw working in the second horizontal framing, and
having its extremity bearing against the table supporting the said frame.
This screw being situate between the hinge or joint of the said frame
and the tool shaft is intended for regulating the elevation of the tool
above the millstone, and thus to burr the latter to a greater or less
depth.
The general arrangement of the parts herein-before referred to is
such as to allow the operator to work the tool in any line or direction
required without leaving his seat. It also admits of the millstone being
dressed on its entire surface, dispensing with the necessity of displacing
the machine at the end of each successive traverse of the tool, the
whole apparatus carrying the tool being so contrived as to turn or rotate
about the axis of the frame.
As to the fourth part of this Invention, rotary motion is imparted to
the diamond tool by means of conc pulleys turning loose on the upper
end of the vertical frame shaft, the same being driven by any prime
or intermediate motor. One of the pulleys or wharves of this conc is
made to drive the corresponding small pulley or wharve on the tool
spindle by an endless band passing over two guide pulleys. The tool
pulley being movable in every direction, the bearings or pivots of the
guide pulleys are fixed at the end of an arm swivelling on a movable
bracket on the frame shaft. By this arrangement the guide pulleys will
always spontaneously assume their proper position with regard to the
tool pulley. There is also a spiral spring which constantly tends to
bring the driving apparatus home to its primary position.