Improvements in Machinery or Apparatus for Grinding and Polishing Lithographic Stones or Marble.
Year: 1890

page_text: Date of Application, 17th July, 1890
Complete Specification Left, 19th May, 1891-Accepted, 20th June, 1891
PROVISIONAL SPECIFICATION.
Improvements in Machinery or Apparatus for Grinding and Polishing
Lithographic Stones or Marble.
I, WILLIAM HIRST, of 50, Heap Street, Barkerend Road, Bradford in the
County of York, Stone Polisher, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in machinery or apparatus for grinding
and polishing lithographic stones or marble to a true surface and its object is to
facilitate the process.
The said improvements consist in oscillating or vibrating the rubber or rubbing
stone in the manner hereinafter described, by which means such rubber or stone is
kept "sharp or rounded on its rubbing face and its action or "bite" considerably
increased.
To carry out my invention 1 employ an ordinary reciprocating table upon which
the stone or stones to be operated upon are mounted and I mount the rubber in a
frame reciprocated in the usual manner at right angles to the motion of the table.
But I provide said frame with a pivoted holder to receive and hold the rubber.
The said pivoted holder is oscillated as it is reciprocated by means of a rod
attached thereto which is approximately vertical at mid-stroke and slides by the
motion of the frame in an eye pivoted adjustably to a pillar or pendant.
It is obvious that two or more rubbers may be thus mounted in the same frame
and the oscillating mechanism may be considerably modified.
DRACUP & NOWELL,
Bradford, Agents.
COMPLETE SPECIFICATION.
Improvements in Machinery or Apparatus for Grinding and Polishing
Lithographic Stone or Marble.
I, WILLIAM HIRST, of 50, Heap Street, Barkerend Road, Bradford in the
County of York, Stone Polisher, do hereby declare the nature of this invention
and in what manner the same is to be performed, be particularly described and
ascertained in and by the following statement :-
This invention relates to improvements in machinery or apparatus for grinding
and polishing lithographic stones or marble to a true surface and its object is to
facilitate the process.
The said improvements consist in oscillating or vibrating the rubber or rubbing
stone in the manner hereinafter described, by which means such rubber or stone is
kept "sharp" or rounded on its rubbing face and its action or "bite" considerably
increased.
To carry out my invention I employ an ordinary reciprocating table upon which
the stone or stones to be operated upon are mounted and 1 mount the rubber in a
frame reciprocated in the usual manner at right angles to the motion of the table.
But I provide said frame with a pivoted holder to receive and hold the rubber.
The said pivoted holder is oscillated as it is reciprocated by means of a rod attached
thereto which is approximately vertical at mid-stroke and slides by the motion of
the frame in an eye pivoted adjustably to a pillar or pendant.
To fully describe my invention reference is made to the accompanying sheet of
drawings forming a part of this specification in which similar letters of reference
indicate corresponding parts in each of the figures.
Figure 1, is a side view of my improved machine looking towards one end of the
table

page_text: Figure 2, is a view, at right,angles to the above, of the reciprocating or rubbing
frame with the cross slides and certain other parts in section to more clearly show
the construction.
Figure 3, is an elevation of one of the oscillating rubber holders with a stone
rubber mounted therein.
Figure 4, is a plan view of the same.
The table A is mounted upon the inverted Vee slides B of the bed plate C and
has a slow reciprocating motion imparted to it by the spur wheel E on the shaft F
engaging the rack G on the underside of the table in a similar manner to the table
of a planing machine or other reciprocating tables. The stone a to be operated
upon is mounted upon the face of the table and is preferably secured in position
between the raised sides a' of such table by the wedges a² ². The bed plate C is
provided with a projection H on one side and H' on the other. The former forms
a bed for the two standards J and J' the latter of which is provided with a
bearing to support the crank shaft K driven in any convenient manner. The
standards J and support one end of the transverse guides L and L and the other
ends of said guides are mounted upon a standard M fixed upon the projection F
of the bed plate. A saddle N is mounted upon the transverse guides LL, and is
connected by the rod O to the adjustable stud P mounted in the slot e of the crank /
so that as such crank is rotated the saddle is reciprocated from side to side over
the table C with a longer or shorter stroke according to the position of the stud P
in the slote of the crank. The saddle N is provided with inner vertical guides y
on the under side between which the frame R is mounted so that it is capable of
vertical adjustment in relation to the table by means of the screws and hand-wheel T.
Bearings, are formed in each end of the frame R in which the rubber
holders W, W are mounted by means of their end journals and . The rubber
holders are made with a loose side and the grinding or polishing stone / is
clamped between such side and the side by the screws j².
The journal of each rubber holder is extended and an arm is rigidly secured
thereto such journals are placed at opposite ends of the frame R and the arms
fixed thereto pass up through slots m in the guides L, L and through the rocking
guides a, n mounted by their journals p,p in the brackets r, r secured, by their studs
passing through the slots t, to the standards V, V fixed upon the guides L, L.
When the saddle N is reciprocated by the rotation of the crank shaft K the
grinding or polishing stones are carried to and fro across the stone a and are
adjusted by the hand screws so as to bear with a suitable pressure thereon. But as
the ends of the arms engaging the rocket guides n are held stationary during this
reciprocating motion the holders W are rocked upon their journals i and and are
thereby rounded on their acting faces and are thus kept what is technically termed
"sharp," in a somewhat similar manner to that when grinding or polishing stones
are used by hand.
As the grinding or polishing stones are thus operated the table is reciprocated so
that they act uniformly over the whole surface of the stone u.
It is obvious that other mechanical means instead of a crank may be employed
to reciprocate the saddle N.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare what I
claim is
A machine for grinding or polishing lithographic stones or marble constructed
and arranged to impart a rocking or oscillating motion to the grinding or polishing
stone or stones during the grinding or polishing process, substantially as herein
shown and described and for the purpose specified.
· Dated this 16th day of May 1891
DRACUP & NOWELL,
Bradford, Agents.