Improvements in Grinding or Pulverizing Machines.
Year: 1894

page_text: Date of Application, 28th Feb., 1894-Accepted, 28th Apr., 1894
COMPLETE SPECIFICATION.
Improvements in Grinding or Pulverizing Machines.
JOHN TOY Jr. Meneage Street Helston Cornwall England Engineer, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention refers to improvements in grinding or pulverizing machinery
described in the Specification of Letters Patent granted to John Toy & Samuel
Henry Stephens, bearing date the 29th day of August, A.D. 1882 & numbered
4128 also in the Specification of Letters Patent bearing date the 22nd of October
A.D. 1887, & numbered 1437187.
This invention refers to improved shaped shoes or rubbers used in machinery
for grinding gold, silver, tin & other partially pulverized ores to extract the
metal therefrom & also for grinding paint, cement, & other hard substances, &
has for its object the improved construction & arrangement of such shoes or
rubbers, whereby the material to be ground is compelled to pass between the
grinding surfaces before it is discharged from the pan; and also a great saving
of power by allowing the ground material to pass out of the pan at the level of
the grinding surfaces, thereby saving the amount of power which is now required
to overcome the burden & friction caused by the accumulation of sand and water
in grinding pans discharging at the top as at present constructed. The improved
construction & arrangement in the shape consists in forming the shoes or rubbers
in the form of an Archimedean spiral of any desired pitch, & either single, double
or (any preferable number), & with a cover cast or fixed on the upper part for
the purpose of keeping the material under treatment from rising above the level
of the top of the shoes or rubbers, there will also be a space of any convenient size
allowed between each section of the spiral to admit of a sufficient amount of
material being ground to pass between the rubbing surfaces. These shoes or
rubbers can be made in sections or whole.
This improvement can be applied to any flat bottom pan grinding machines dow
in use.
In order to more fully illustrate and describe the manner in which I carry this
invention into effect I will now proceed to further describe the same with reference
to the accompanying drawings.
Fig. 1. is a vertical cross section of a pan pulverizer showing in section the shoes
or rubbers A. A. with the cover B. in their working position, resting on the bottom
shoes or rubbers C. C. which are made either similar to the Archimedean spiral top
shoes or rubbers or plain, in this case they are shown plain.
Fig. 2. is a plan of the shoes or rubbers shown without the cover B. & is a
double Archimedean spiral, each spiral marked D. D. D. and E. E. E. respectively.
The parts marked F. F. F. are the spaces between each section of the spiral.
Fig. 3. is a section of Fig. 2. through A. B. showing the cover B, with the
lugs G. G. for attaching the same to the muller L.
Fig. 4. is a plan of the shoes or rubbers shown without the cover B. and is a
single Archimedean spiral marked H. H. H.
Fig. 5. is a section of Fig. 4. through A-B.
The general operation of the machine is as follows:-The material to be ground
is fed to the machine by any suitable launder J. inside the circular ring or
division K. where there are suitable holes between the arms of the muller L to
allow it to pass into the recess or well M, mixed with the necessary quantity
of water, and by the currents therein carried to & between the grinding

page_text: surfaces A. & C.
While the material has been fed in from the launder J.
the shaft P. is being rotated by means of the bevil wheels R. R. &
thus communicating rotary motion to the upright shaft S and driver T. with the
muller L. & the shoes or rubbers A. A. attached thereto. The advantages
arising from this arrangement & construction of the shoes or rubbers is that the
material which is fed into the machine cannot pass to the periphery of the pan
without first being forced between the grinding surfaces & with the cover B.
cast or fixed on the upper part of the shoes or rubbers A. A. the material cannot
rise above the level of the top of the shoes or rubbers, & is delivered at the
mouthpiece U.
This improvement is also applicable to grind other substances than ores, such as
paints, cements, etc.
Having now particularly described and ascertained the nature of my said
invention & in what manner the same is to be performed, I declare that what
I claim in the shape of the shoes or rubbers to be in the form of an Archimedean
spiral, either single, double (or any preferable number) substantially as herein
described and with reference more particularly to Figures 2, 3, 4, 5 of the
accompanying drawings.
Second. The general combination of the above claims with any description of
grinder on the pan or millstone principle.
Dated this 27th day of February One thousand eight hundred and
ninety-four