Year: 1888

page_text: Date of Application, 13th Aug., 1888
Complete Specification Left, 4th May, 1889
Complete Specification Accepted, 8th June, 1889
I, CHARLES JOHN POTTER of Heaton Hall, Newcastle, Cement Manufacturer, do
hereby declare the nature of this invention to be as follows:-
In mounting mill-stones it is usual that the shaft which carries the upper or
running stone should revolve in a metal box, which is held in place in the eye of
the bed stone by wooden wedges.
.
Now according to my invention I carry the box in which the shaft revolves entirely
independently of the bed-stone, making part of a casting on which the bed-stone
rests. I make the bed-stone with a circular eye like the eye of the upper stone, in
place of with a square eye as heretofore. The casting before mentioned has a
cylindrical boss which enters the eye of the bed-stone and the bed-stone is made fast
to it by clamping screws.
Dated this 12th day of Anonst 1888.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: Figure 2 is a plan of the same with the shaft and upper stone removed.
Figure 3 is a sectional elevation showing a pair of stones mounted in my improved
manner.
Figure 4 is a plan with the shaft and both the stones removed.
In Figures 1 and 2 a is a base plate or pan carried by columns a¹ a¹. b is the
driving shaft.
c is the upper stone carried upon the upper end of the shaft in the usual
manner. d is the lower or bed-stone. d' is a packing beneath the bed-stone and on
which it rests. e is a square metal box fixed into the eye of the bed-stone d; in this
box the upper bearing for the shaft b is formed. f. f, are wooden wedges by which the
square box e is fixed in its place in the square eye of the bed-stone d.
In Figures 3 and 4 the parts a, b, c, are as already described but the bed-stone d is
made with a circular eye similar to that of the upper or running stone; it, with its
packing d rests upon the flange g¹ of a casting of which the box g² also forms a part,
and in this box the upper bearing for the shaft 6 is formed. g³, g³, is a cylindrical
boss also forming part of the same casting. The bed-stone d surrounds this boss, and,
when the stone is in place, it is locked by means of the clamping screws g*, g*.
The casting is fixed in its place in the pan a.
My improved method of mounting presents the following advantages
:-
1. It much simplifies the operation of raising the bed-stone when this becomes worn ;
with the ordinary mounting great care is required after removing the square box e to
fix it again perpendicularly in the line of the shaft; the labour in removing the wedges
and in replacing them again is considerable, and a good deal of delay necessarily

page_text: takes place. Sometimes also, in consequence of the box getting out of place, breakage
of the gear teeth occurs. In my improved mounting the bed-stone can be raised
without interfering in any way with the box, which always remains perpendicular and
keeps the wheels properly hung.
2. The running stone when nearly worn down may be converted into a bed-stone,
the square eye of the latter being now dispensed with.
3. The form of the eye is the same in the running stone and the bed-stone; this is
not only a great convenience but a saving in the first cost of the stones; the square
eye being more difficult to construct than the round one.
4. As the running stone when worn down can be converted into a bed-stone
the eye burrs to carry the driving bar need not be made so deep and in this way a
saving is made.
5. In dressing the bed-stone there is also a saving, for when the stone is made with
a square eye the part around the eye (surrounded by a dotted circle in Figure 2) has
to be cut away with chisels as the rest of the stone wears; this labour is avoided when
bed-stones with large circular eyes are employed.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The combination with a bed-stone having a circular eye of the arrangement
described in which the box containing the upper bearing for the driving shaft is
carried independently of the bed-stone by a casting on which the bed-stone rests.
2. The improved centre piece for a mill bed-stone having parts g¹, g³, 9³, substantially
as described.