Metal, and other Hard Substances.
Year: 1887

page_text: Metal, and other Hard Substances.
I JAMES SHARON MCCOY of 395 Jefferson Avenue, Brooklyn State of New York,
United States of America, Manufacturer do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
My Invention consists first in the process or method of carving marble and other
stone and making a smooth surface without sand-rubbing or filing, with a stroke
machine whose striker acts so rapidly as to impart practically a continuous motion to
the cutting tool, thus carving and at the same time smoothing the cut surface by a
reciprocating, as distinguished from a rotating or a back and forth planing, motion.
The machine I use in carrying out my new process or method is of the pneumatic
class wherein the piston or striker carries the slide valve and is arranged to deliver
blows upon the inner end of a spindle by a pressure of air forced into or through the
cylinder in which the striker is held, and by my invention I can successfully plane
stone with a stroke tool producing a smoother, finer, grained texture or finish than
can otherwise be produced. By this method or process, the striker must have a very
high speed estimated at 15,000 strokes per minute, and by it the surface seems to be
cut or pared off without breaking, chipping, or fracturing the finishing surface to any
depth so that very little rubbing is required to produce a perfect polish. Another
peculiarity is that both a light cut or "kerf" and a comparatively deep one may be
made in succession by the same machine, or partly shallow and partly deep at the
same time. Thus, with a curved edge bit or chisel, a bead a groove or a moulding
may be cut in one operation, or any variety of carving can be wrought out
expeditiously. Thes uccessive strokes of the bit or tool are so very rapid that there
is not time between them for the tool to rebound or quit contact with the material
and when each stroke imparts mechanical energy the tendency or ability to rebound
has departed from the tool and the tool thus makes a practically continuous progressive
movement and pares off or shaves and also "planes "the material, a result not
hitherto accomplished. Furthermore, in cutting and hammering stone and metal so
as to make a smooth surface, especially in planishing sheet metal as well as in other

page_text: kinds of work to which my invention is applicable, a short quick and percussive blow,
as distinguished from a long dead blow, is essential. In order that the machine
may deliver this character of blow and run at the high speed mentioned, I construct
the striker of such diameter relatively to the diameter of the cylinder that there is
an appreciable space between the striker and the cylinder. To this end also, I place
the main induction port at the bottom of the cylinder so that the entering air will
lift the striker in the cylinder, thus reducing friction and obtaining the aid of gravity
and for this purpose 1 also make the distance in the cylinder between the upper
induction port which serves to start the slide valve and the lower induction port
which serves to return the slide valve, less than the distance between the upper
induction port in the cylinder which starts the slide valve at the beginning of the
action of the machine and the head of the tool holding spindle so that an air cushion
will be maintained between the end of the striker and the head of the spindle. And
to this end also, I place the induction port in the cylinder which bears upon the slide
valve at the beginning of the stroke with its corresponding eduction port and the
induction port in the cylinder which bears on the end of the valve at the termination
of the stroke with its corresponding eduction port, in such proximity to each other
relative to the diameter of the slide valve chamber or induction and eduction passages
leading thereto, that very thin lines of action are attained so that the striker will give
a short, quick, and percussive stroke.
1
Reference is to be had to the accompanying drawings forming part of this speci-
fication in which figure 1 is a perspective view shewing the manner of applying the
tool to the work, to accomplish my new method. Figure 2 is a longitudinal sectional
elevation of the pneumatic tool used in carrying into effect my new method. Figures 3
and 4 are reverse side elevations of the cylinder of the tool, the outer shell or jacket
being removed. Figure 5 is a side view of the striker, shewing a valve chamber of
small diameter with induction and eduction passages leading into it. Figure 6 is a
cross-section taken on the line x-x of figure 2; and figure 7 is a side view of the
valve removed. Similar letters of reference indicate corresponding parts in all the
figures.
In carrying my invention into effect, I employ a pneumatic tool in which A repre-
sents the striker and B the casing or cylinder composed of upper and lower parts
screwed together as shewn in figure 2. Surrounding the cylinder is the jacket C
which together with grooves and flattened surfaces formed in and upon the outer
surface of the cylinder (and hereinafter fully described) form the air ducts and passages
through which the compressed air enters and exhausts from the cylinder. The lower
part or point C¹ of the casing or cylinder carries the spindle D that holds the point E
and upon the spindle within the point C' is placed a coiled spring F the office of which
is to return the spindle after each down stroke of the striker A. The upper part of
the cylinder B is formed with the air-inlet passage a figure 4 and exhaust passage b
figures 2 and 3 and it is faced off at c figure 4 and on the opposite side at d d³ d
(shewn in figure 3). In the flat surface c is formed the cylinder induction port e and
the air inlet passage a opens into said flat surface c. The exhaust passage b opens
out from the Hat surface d and in the flat surfaces d' d' are formed in the cylinder the
exhaust-ports ff. From the flat surface c, the cylinder is grooved as shewn at g
and on the opposite side as shewn at g¹. The groove g leads to the port / (see full
lines figure 2 and dotted lines figures 3 and 4) while the groove g' leads to the port hª.
From the flat surfaces d¹ di are formed the grooves i¹. The groove i leads
to the port while the groove leads to the port (both ports shewn in
full lines figure 2 and in dotted lines in figures
and 4).
The striker A is
made of less diameter than the internal diameter of the cylinder B so that
a space is formed between the inner walls of the cylinder and the striker,
and the striker is formed with the transverse valve chamber L' in which is placed the
slide valve L and the striker has formed in it the passages k k¹ which reach through
to the valve chamber and these openings or passages coincide or stand in the same
plane with the exhaust ports ffl respectively. The striker also has a passage / formed
in it which also reaches through to the valve chamber L' and this latter passage.1

page_text: coincides with or stands on the same plane with the inlet port e made in the cylinder B,
and the striker also has the longitudinal passages m'n formed in it which reach
respectively from the valve chamber to the top and bottom of the striker as shewn in
dotted lines in figure 2, through which the compressed air enters and exhausts from
both ends of the cylinder for reciprocating the striker. The valve L is circumferentially
grooved, as shewn at pp so that in its reciprocation caused by air entering the ports jj¹
or hh it will open and close all the air passages made in the striker.
The operation is as follows;-The striker A being in its upper position, air admitted
to the induction port a enters the passage formed by the flat surface c and passes
through the port e and port h moving the valve L to close passage k¹ and to connect
passages elm thus admitting air above the striker A and at the same time the valve
connects the passages kfn to allow exhaust from below the striker through the space
formed by the flat surfaces d d¹ and passage b. Then the air through the passage gl
and port h² moves valve L to close the passage k and to connect passages e ln to admit
air below the striker and to connect passages m k¹ and f to open the exhaust from
above the striker, and so on alternately, causing the striker to have a rapid reciproca-
tion. The air contained in the valve chamber L¹ at the ends of the valve, is exhausted
with each movement of the valve through the ports jj alternately.
The distance between the transverse plane of the port h, and that of port h¹ together
with the diameter of the valve chamber L', determines the length of reciprocation of
the striker A, and these ports are arranged so that the cut-off by the valve L of the
exhaust through the passages mn in the striker, is timed to maintain a cushion
of air at both ends of the striker, so that there is no beating of the striker upon the
cylinder and no beating of the striker upon the spindle D.
The ports h are arranged in the cylinder a distance from the spindle D (when
seated) somewhat greater than that from the lower end of the striker to the valve
chamber L', so that the air cannot all exhaust from the cylinder but a cushion of air
will be always maintained between the striker and the spindle which renders the blow
of the striker percussive and effective without battering either the spindle or striker.
When, owing to the size of the tool or otherwise it is desired to economize weight in
the valve L, I use a valve of small diameter and form in the striker, at either side
of the valve chamber L', the small grooves 99, to direct the compressed air to and
from the valve chamber through the inlet and exhaust ports in the cylinder, and by
these grooves the same short, quick percussive blow may be maintained, by making
them of proper length relatively to the distance between the ports hj and h¹ j¹.
The striker being of smaller diameter than the cylinder B, thus forming the spaces,
the compressed air entering the cylinder completely envelopes the striker so that it is
carried in a state of flotation, and this enveloping of the striker with air in a surround-
ing space s also prevents friction and danger of the striker binding or sticking in the
cylinder; and in most cases the tool will be constructed so that the induction port e
will be lowermost, so the force of the air entering the cylinder will lift the striker A
in the spaces and thus, to a large degree overcome the friction due to the gravity
contact of the striker with the cylinder.
In performing the process the tool and pit E, are to be applied to the material to
be wrought upon as illustrated in figure 1, the length of the bit being held at an acute
angle to the surface to be formed.
Instead of using compressed air, I may use steam with like action and results.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is-
1. The method of making a smooth surface on stone, metal or other hard substance
by means of a reciprocating stroke machine whose action is so rapid as to be practically
continuous.
2. The method of making a smooth surface on stone, metal or other hard substance
by applying to the material by hand or otherwise, a bit in a spindle acted upon by a
spring and a reciprocating striker which moves with great rapidity in a state of

page_text: flotation in compressed air in an air cylinder formed by an appreciable difference
in the diameter of the metallic cylinder and the striker.
3. The method herein described of making a smooth surface on stone, metal or
other hard substance, which consists in applying to the material, by the hand or other-
wise, a bit in a spindle acted upon by a spring and a rapidly reciprocating striker,
whereby a planed surface is produced upon the material, substantially as described.
4. The method herein described of making a smooth surface on stone, metal or
other hard substance, which consists in applying to the material, by the hand or other-
wise, a bit in a spindle acted upon by a spring and a rapidly reciprocating striker, the
force of the spring being so adjusted and the striker being driven so rapidly that a
practically continuous progressive motion of the cutting bit is imparted, whereby
à planed surface is produced upon the material, substantially as described.
Dated this 22nd day of November 1887.