IMPROVEMENTS IN MACHINERY FOR DRESSING OR POLISHING STONE
Year: 1876

page_text: LETTERS PATENT to Walter Grant, of Johnstone, in the County of Renfrew,
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN MACHINERY
FOR DRESSING OR POLISHING STONE."
baled the 23rd September 1870, and dated the 11th May 1870
PROVISIONAL SPECIFICATION left by the said Walter Grant at the Office
of the Commissioners of Patents on the 11th May 1876.
WALTER GRANT, of Johnstone, in the County of Renfrew, North Britain, Engi-
"IMPROVEMENTS IN MACHINERY FOR DRESSING OR POLISHING STONE."
neer.
This Invention, which relates to improvements in machinery for dressing or
polishing stone, has reference to that class of stone polishing machines for which
Letters Patent were granted to James Coulter and Herbert Harpin on the 18th day
of January 1865, No. 154.
In the Specification of the said James Coulter and Herbert Harpin the machine
therein described consists of a circular and concentrically revolving table below, and
a horizontal sliding frame above, in the table and frame; the stones to be polished
are placed so that they rub upon and dress or polish one another.
According to the improvements constituting this Invention the upper or horizon-
tally moving frame is dispensed with, and in place of it and the lower concentric
table two eccentric tables, revolving in opposite directions, are substituted. By
virtue of these tables revolving eccentrically and in opposite directions a more rapid
rate of dressing or polishing is attained.
For the purpose of inspecting the surfaces being rubbed from time to time, that
is to say, by separating them from one another, and also for the purpose of increas-
ing the stress by which the rubbing surfaces are pressed together, the upper table is
provided with a screw and hand wheel for operating it; also with gearing and
shafting, to bring the same within reach of the attendant, so that by turning the
hand wheel in one direction the upper table is lifted, and by turning it in the
opposite direction it is forced down on the lower table with any required degree of
pressure.
For the purpose of still further increasing the intensity or efficiency of the rub-
bing or polishing action either the upper or lower table, or both of them, have in
addition to their eccentric sliding motion a horizontal sliding motion imparted

page_text: to them, this being effected by connecting the bearings in which their shafts are
carried either to an eccentric reversing screw camb or the equivalent thereof, so that
as these rotate the tables with their shafts and bearings are reciprocated in guides.
Under another modification the horizontal sliding motion may be effected by
carrying the eccentric tables upon rotating carriers fixed upon the driving shaft of
cach table, and the carriers are fitted with rollers so as to allow the tables to be
moved backwards and forwards on them with a minimum of friction whilst rotating.
The movement of the tables backwards and forwards upon the carriers is effected
by guides placed round about and eccentrically to the revolving axles of the tables.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Walter Grant in the Great Seal Patent Office on the 10th November
1876.
WALTER GRANT, of Johnstone, in the County of Renfrew, North Britain, Engi-
neer. "IMPROVEMENTS IN MACHINERY FOR DRESSING OR POLISHING STONE."
My said Invention, which relates to improvements in machinery for dressing or
polishing stone, has reference to that class of stone polishing machines for which
Letters Patent were granted to James Coulter and Herbert Harpin on the 18th
day of January 1865, No. 154.
In the Specification filed in pursuance of the Letters Patent above referred to the
machine described by the said James Coulter and Herbert Harpin consists of a
circular and concentrically revolving table below and a horizontal sliding frame
above. On the table and in the frame the stones to be polished are placed so that
they rub upon and dress or polish one another.
According to the improvements constituting my said Invention the upper or
horizontally moving frame is dispensed with, and in place of it and the lower
concentric table two eccentric tables, revolving in opposite directions, are substituted,
and by virtue of the tables being made so to revolve a more rapid rate of dressing
or polishing is attained.
And in order that my said Invention may be properly understood, I now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
annexed Sheet of Drawings, and to the letters and figures marked thereon, that
is to say :-
On the Sheet of Drawings hereunto appended Figure 1 is a vertical section;
Figure 2, an end elevation; and Figure 3, n plan of one arrangement of the im-
proved stone dressing or polishing machine as constructed in accordance with my
said Invention.
The apparatus consists of a framing A, the sole or bed plate whereof is shewn in
part plan at Figure 4, and between the sole and the top member of the frame a
vertical shaft B is supported in bearings. Towards the lower part of the said shaft
is placed an eccentric C, which is formed with a long sleeve, supported at its lower
end in a footstep bearing D, placed or formed on the sole or bed plate of the
machine. The lower table E, on which a portion of the stones to be polished or
dressed are placed is carried on the eccentric C, as seen more particularly at
Figure 1, and the table is rotated by a bevil wheel F fixed on the sleeve of the
eccentric, and geared with a pinion G situate on the driving shaft H, which is sup-
ported in bearings in the frame A. The upper table J, holding the other portion of
the stones to be dressed or polished, is also similarly carried on an eccentric J₁,
situate on a square portion of the shaft B, which is rotated by the bevil wheel K,
fixed thereon and geared with the pinion L, carried on a second driving shaft M.
The bevil gearing K, L, and the shaft B are rotated in the opposite direction from
the bevil gearing F, G, so that in driving the machine the tables E and Jare caused
to revolve eccentrically also in opposite directions, by which means a more rapid

page_text: rate of dressing or polishing of the stones is attained than with the class of machines
herein-before referred to.
For the purpose of from time to time inspecting the surfaces being rubbed of the
stones, that is to say, of separating them from one another, and also for the purpose
of increasing the stress by which the rubbing surfaces are pressed together, the
eccentric carrying the upper table J is attached by the rods or links N to a cross
head O, through a sleeve t, at the interior of which a screw P passes, the screw
being at its lower end secured to the top member of the frame A, as shewn. The
rods N are attached to the eccentric by a ring b, which permits of the rotation of
the table J without rotating the said rods; and when it is desired to inspect the
rubbing surfaces of the stones, or to force such surfaces into greater frictional con-
tact with each other the cross head O is raised or lowered vertically by the attendant
turning the hand wheel c and shaft d, whereon a bevil pinion is secured and
geared with a corresponding wheel f, carried on the sleeve a, through which the
screw P passes. The bracket in which the lower end of the shaft is supported is
made with a slotted hole, as is also the arm of the cross head O, or the bracket may
be hinged or jointed to allow of the shaft rising or falling correspondingly with the
cross head O.
In lieu of eccentrically rotating the tables E and J in opposite directions by bevil
gearing actuated from different driving shafts, as herein-before described, the tables
may be so rotated by the arrangement of bevil gear, illustrated at Figure 5 of the
Drawings, in which the evil wheel F situate on the sleeve of the lower eccentric and
the bevil wheel K which through the shaft B drives the upper eccentric are rotated in
opposite directions by one pinion Q. A shield is, or may be, placed above the bevil
gearing, as seen at R, Figures 1 and 2, to prevent it from being fouled.
For the purpose of still further increasing the intensity or efficiency of the rub.
bing or polishing action the lower table may have in addition to its eccentric
revolving motion a horizontal sliding motion imparted to it. Figure 6 on the
accompanying Drawings represents in vertical section a machine constructed in
accordance with my said Invention, and wherein the lower table A is so operated.
To effect the horizontal motion of the table A it is mounted by means of a
hollow pillar or support B on a carriage or truck C, which runs upon a platform D
forming part of or attached to the sole or bed plate of the machine. The carriage
or truck C is attached by a connecting rod or link to a crank E fixed on the upper
end of a vertical shaft, which is also supported on the sole or bed plate. A bevil
wheel b secured on the shaft a communicates reciprocating motion to the carriage or
truck, being geared with a corresponding wheel e, situate on one end of a horizontal
shaft F, at whose opposite end a worm wheel is fixed and geared with a tangent
screw placed on the lower end of the vertical spindle or shaft F', which is rotated
from the driving shaft G by the spur wheel e, pinion f, shaft g, and bevil gearing H,
as shown. The upper table K is rotated eccentrically with the shaft F¹ by means
of the eccentric I, in the manner herein-before described, and the lower table A,
which is or may be supported on rollers x, is rotated eccentrically with the upper
table, and in the opposite direction to it by the spur wheels M, e, shaft N, and bevil
gearing O. The spur wheel M is keyed to the shaft N by means of a feather and
groove, so as to permit of the shaft sliding through the boss of the wheel when the
carriage or truck C is reciprocated, as herein-before described.
Instead of communicating horizontal sliding motion to the lower table A, such
motion may be imparted to the upper table K in addition to its eccentric rotatory
motion, or, if desired, eccentric, rotatory, and sliding motions may be communicated
both to the upper and lower tables by cranks, cambs, or the equivalent thereof,
which in rotating reciprocate the tables with their bearings in guides.
Under another modification, illustrated in vertical section at Figure 7 of the
Drawings, the motions of the lower or upper or both eccentric tables may be effected
by rotating carriers. On the Drawing the lower table A is shewn so supported on
a carrier B and on rollers G, the carrier being secured on an outer shaft C which
drives the lower table, the shaft D for the upper table passing through it." Bevil

page_text: wheels, gearing with a pinion I, which drives them in opposite directions, are fixed
on these separate shafts. The carrier B is fitted with rollers E, which are situated in
a slot or channel in the under part of the table A, and these rollers bearing against
the sides of the said channel rotate the table A in a circular path eccentrically to
the rotation of the upper table, by which means a compound dressing or polishing
motion is obtained, the upper table being also rotated eccentrically on its axis, in the
manner herein-before described. The table A rotates in guides M placed round
about it, and eccentrically to the revolving axle C of the carrier B.
Having now described and particularly ascertained the nature of my said Inven-
tion and the system, mode, or inanner in or under which the same is or may be used
or practically carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,―
First. The improved stono dressing or polishing machine herein-before described
and shown at Figures 1, 2, and 3 of the appended Drawings or any mere modifica-
tion thereof wherein eccentrically revolving tables moving in opposite directions
are employed, as set forth.
Second. The producing of a sliding or reciprocating motion in stone dressing or
polishing machines (in addition to the eccentric revolving motion) by the mechanism
shewn at Figure 6 of the Drawings, or any mere modification or equivalent
thereof.
Third. The mechanism herein-before described and shown at Figure 7 of the
Drawings, or any merc modification or equivalent thereof, for producing a compound
eccentric rotatory motion of the table or tables of stono dressing or polishing
machines, substantially as set forth.
Fourth. The application or employment of the screw apparatus for separating
the tables, or for pressing the stones held therein against one another, substantially
as herein-before described with reference to the Drawings hereunto annexed.
In witness whereof, I, the said Walter Grant, have hereunto set my hand
and seal, this Ninth day of November, One thousand eight hundred and
seventy-six.
WALTER GRANT. (L.S.)