IN MACHINERY OR APPARATUS FOR CRACKING OR DRESSING MILL AND OTHER STONES
Year: 1871

page_text: LETTERS PATENT to Benjamin Bloomfield, of Mill Cottages, Reading,
"IMPROVEMENTS
in the County of Berks, Miller, for the Invention of
IN MACHINERY OR APPARATUS FOR CRACKING OR DRESSING MILL AND OTHER
STONES"
Sealed the 10th November 1871, and dated the 17th May 1871.
PROVISIONAL SPECIFICATION left by the said Benjamin Bloomfield
at the Office of the Commissioners of Patents, with his Petition,
on the 17th May 1871.
I, BENJAMIN BLOOMFIELD, of Mill Cottages, Reading, in the County
of Berks, Miller, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR CRACKING OR DRESSING
MILL AND OTHER STONES," to be as follows:-
This Invention relates to the construction of machinery or apparatus
for cracking or dressing mill and other stones by the percussive or
striking action of a tool actuated by a crank or eccentric.
I arrange a bed plate on the stone to be cracked or dressed; this
plate is perfectly true on its under face, and the upper part of it is
formed with circular faces for supporting a standard, in one face of

page_text: which a kind of slide rest is formed so that a plate carrying the tool
holder can be moved in two directions, the movement being governed
by a lever and link pinned to an upright on the standard before referred
to. The plate has a projecting bracket standing out from the front
of it, and this supports a box in which the ram or holder is free to rise
and fall, the box having an independent movement to the front and
rear by a screw rotated by a catch paul taking into the teeth of a
wheel on its end, the wheel being star toothed to enable the paul to
work from either side of it. The bracket has uprights on it for sup-
porting a crank or eccentric shaft, and this is rotated by hand or by
power from an over head motion as desired. The connecting rod has a
screw bolt on one end, and this is adjustable in the head of the 'ram to
regulate the length of stroke and to permit of the tool being lowered
as it becomes worn. The standard can be bolted to the bed plate at
any angle so that the tool which is of the ordinary "bill" kind may
cut lands and furrows in a millstone, in which case the tool may travel
in two directions only by throwing the ratchet and paul out of gear,
or by keeping them in gear and not operating the lever or plain surface
dressing can be accomplished by keeping all the parts in gear, when
the tool would travel to and fro in two directions in
any suitable manner.
If circular stones are being cracked or dressed I arrange two apparatus
upon the bed plate, and these may work in conjunction or separately as
desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Benjamin Bloomfield in the Great Seal Patent 25
Office on the 17th November 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
BLOOMFIELD, of Mill Cottages, Reading, in the County of Berks, Miller,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 30
Letters Patent, bearing date the Seventeenth day of May, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Benjamin Bloomfield, Her special
licence that I, the said Benjamin Bloomfield, my executors, adminis- 35

page_text: trators, and assigns, or such others as I, the said Benjamin Bloomfield,
my executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN MACHINERY OR APPARATUS FOR CRACKING OR DRESSING MILL AND
OTHER STONES," upon the condition (amongst others) that I, the said Ben-
jamin Bloomfield, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Benjamin Bloomfield, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the Drawings
hereunto annexed, that is to say :-
This Invention has for object the cracking or dressing of stone, slate,
and other bodies of a similar nature by the percussive or striking action
of a tool or tools actuated by a crank or eccentric, the tool having a
movement in more than one direction by mechanism for the purpose
of accomplishing the object in view.
According to one arrangement, such as I have shown in Figure 1 of
the accompanying Drawings, I attach a bed or base plate a upon a
fixed support 6, the top surface of the bed plate a being smooth to
permit of a standard d turning round upon it in an easy manner by
hand into any position, and be there retained by a tightening nut e
on the end of a centre bolt which passes through the standard for the
purpose. The standard & has a dovetail or V-shaped strap or plate f
centred or fixed upon it which is clasped by a bracket 9 free to slide
from end to end of the plate f, or to such a distance as to suit the length
of cut or dressing the stone or other body is intended to receive, the
to-and-fro movement being effected by an attendant continuously or.
intermittently turning the handle h, the spindle of which is in gear
with a pinion on a shaft inside it. The opposite end of the shaft has
on its outside end another pinion gearing into a rack on the plate f so

page_text: that it moves when the handle is turned. This bracket is of any length,
so as to cover the width of the largest stone or body to be dressed, and
its outer end is supported by a foot i provided with a roller ; to run
upon the surface of a plate ; to prevent any drooping of the over-
hanging end of the bracket. The projecting or overhanging bracket g
is also V-shaped on its edges to enable a slide k to be moved along it
by a threaded shaft as occasions require it, by the attendant acting
upon the handle m which throws the paul n successively into the teeth
of the wheel o mounted upon the shaft 7, the paul being double faced
to permit of the movement taking place in either direction. The slide k
has two uprights p, p, for supporting at their upper ends the crank
shaft q, the strap of which is secured to it and to the tool holder 8,
so that at each rotation the tool is lifted a distance corresponding to
the pitch of the crank, and then to fall by its own weight down upon
the stone placed on a trolly t under it to crack or dress it as desired, the
degree of percussive force being obtained from the weight of the tool.
holder and the height from which it falls. The tool u is held in the lower
part of the holder by screws which may be arranged through the sides
The crank handle v
as shown, or in some other convenient manner.
for giving the necessary motion is held in a bracket wo on the outside
of one of the uprights p, and carries a toothed wheel x in gear with
a pinion y on the crank shaft, so that at each revolution of the crank
handle the tool gets two or more falls according to the respective
diameters of the toothed wheel and the pinion y. I fit screw bolts in the
slide or bracket g for fixing it at any part of the plate when a to-and-
fro movement across the stone only is required; in that case the handle
m would be moved in conjunction with the crank handle v, but when
a hole only has to be cut in the stone this movement is not necessary.
The distance to which the tool can be caused to fall is regulated by
the screw z which passes through a lip 1 projecting from the holder 8,
its lower end pressing upon the clip or slide in which the holder is
mounted, as will be understood by referring to the Drawing. The
standard d being centred upon the centre bolt or fulcrum pin allows
the apparatus to be set at any angle for diagonal cracking or dressing,
so that grooves, furrows, or channels can be cut in the stone or other
body by the tool when required.
For cracking or dressing mill or other circular stones or slates I make
the bed or foundation plate so that it can be laid upon the stone and
shifted round the centre or eye to suit the particular pattern or plan

page_text: to which the lands and furrows have to be cut or shaped. This will
be understood by referring to Fig. 2, in which a circular stone shown
with the bed plate and apparatus mounted thereon is arranged. The
bed plate is shown double so that two sets of furrows can be made at
one time, that is if two complete apparatus be fitted over the fulcrum
pins A, one of each of which is at opposite sides of the centre or eye.
I maintain the distancing from the centre by dropping a plug or
fixing" C, shown separately in Figure 3, into the eye, and then tem-
porarily attaching a socket or frame B on the bed plate to it by screw
bolts; by this means the bed plate can be adjusted truly with the
centre of the stone. This is particularly the case with the "runners,"
but with the "bed stone" the frame B need only to be passed over it,
and it can then be adjusted to the spindle by the screws.
There are other arrangements of mechanism by which percussive
blows of a tool could be obtained substantially and for the purposes
recited and these would vary according to the position or the nature
of the stone, slate, or other body to be operated upon.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,―
Cracking or dressing stone, slate, or other similar bodies, by a
tool or tools arranged in or to an apparatus as described and shown
in Figure 1.
Secondly. I claim the combination of a bed plate with fulcrum pin
and a standard for supporting sliding frames, when such are used in
the manner and for the purposes set forth.
And, thirdly. I claim the means for obtaining a true position of
the apparatus from the centres of millstones or grinding bodies by
which the lands and furrows can be cut or formed as described and
shown.
In witness whereof, I, the said Benjamin Bloomfield, have here-
unto set my hand and seal, this Eleventh day of November
One thousand eight hundred and seventy-one.
BENJAMIN BLOOMFIELD. (L.S.)