IMPROVEMENTS IN APPARATUS FOR DRILLING, GRINDING, OR OBSCURING AND ORNAMENTING GLASS OR OTHER HARD SUBSTANCES, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES FOR WHICH A BLAST OF AIR IS REQUIRED, OR FOR EXHAUSTING GASES OR AERIFORM FLUIDS."
Year: 1877

page_text: LETTERS PATENT to Jeremiah Eugene Mathewson, of Gray's Inn Road; in
the County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS
IN APPARATUS FOR DRILLING, GRINDING, OR OBSCURING AND ORNAMENTING
GLASS OR OTHER HARD SUBSTANCES, PARTS OF WHICH IMPROVEMENTS ARE
ALSO APPLICABLE TO OTHER PURPOSES FOR WHICH A BLAST OF AIR IS
REQUIRED, OR FOR EXHAUSTING GASES OR AERIFORM FLUIDS."
PROVISIONAL SPECIFICATION left by the said Jeremiah Eugene Mathewson
at the Office of the Commissioners of Patents on the 23rd April 1877.
JEREMIAH EUGENE MATHEWSON, of Gray's Inn Road, in the County of Middle-
sex, Engineer. "IMPROVEMENTS IN APPARATUS FOR DRILLING, GRINDING, OR
OBSCURING AND ORNAMENTING GLASS OR OTHER HARD SUBSTANCES, PARTS OF
WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES FOR WHICH A
BLAST OF AIR IS REQUIRED, OR FOR EXHAUSTING GASES OR AERIFORM FLUIDS."
In operating upon the surface of glass, stone, marble, wood, metal, or other hard
substances, by means of a blast of sand for the purpose of drilling, grinding,
obscuring or ornamenting the same, the articles to be operated upon have been
usually confined in a close chamber, and the sand has been impelled with con-
siderable force downwards by means of a blast of air that has been driven forward
by a fan or blower.
For many articles the machinery or apparatus heretofore employed for operating
with the sand blast in this manner is of a very cumbrous and expensive character,
and great inconvenience has been experienced from the escape from the close
chamber of very fine dust into the chamber where the machine is at work.
The first part of the present Invention has for its object to obviate these incon

page_text: veniences, and to reduce the cost of the apparatus. To this end, instead of forcing
(into a close chamber) with the sand a plenum of air under pressure as heretofore
I, by means of an exhausting apparatus produce a partial vacuum in the close
chamber, and the external air, which rushes into this chamber to fill this
vacuum, is made to pass up a narrow pipe or channel, and carry with it
a regulated quantity of sand, which is supplied to the trumpet mouth at the
lower end of the air pipe or channel, which is left open for the purpose.
It will of course be understood that the construction and arrangement of the
various parts of the apparatus will vary according to the character and form
of the articles to be operated upon, but the principle of working will be same in
all cases.
The simplest form of apparatus is that employed for drilling holes in glass plates
or sheets, or for countersinking cells in glass plates. This machine consists of a
close chamber constructed, by preference, of a sheet metal and of a cylindrical
form. From the upper part of this chamber rises an inclined air-tight passage
or flue, and the upper part of this passage (which is of considerable cubical
contents compared with the cylindrical close chamber) is made to communi-
cate with any suitable air-exhausting apparatus (such, for instance, as that
hereafter described, and which forms part of the present Invention), so that a partial
vacuum may be produced in the cylindrical close chamber. On the other side of
this chamber is fixed a smaller chamber, provided with a flat horizontal cover,
in which is made a circular hole to receive a stencil plate, which may be per-
forated with any desired pattern, from a simple round hole up to an elaborate
pattern or design.
Immediately below the opening for the stencil plate is fixed a vertical pipe open
at the top, and provided at the lower end with a trumpet mouth which projects
down through the casing, and is therefore open to the external air.
Under the open trumpet mouth is placed a flat circular disc, which is mounted
on a bracket that is capable of vertical adjustment, so that the distance of the
circular disc from the open trumpet mouth may be regulated with accuracy. By
the side of the small chamber is fixed a tube connected with a vessel placed above
and containing sand which passes from the vessel down the tube, and is deposited
in an uniform and regular manner on the circular disc below the trumpet
mouth.
The sand pipe is provided at its lower end with an adjustable regulator, whereby
the quantity of sand delivered can be controlled with accuracy. It will now be
evident that if a partial vacuum be induced in the cylindrical close chamber by
means of the exhausting apparatus the external air will rush into the trumpet
mouth of the vertical tube with considerable force and velocity, and will carry
with it the sand which is dropping in a steady stream from the sand pipe on to the
circular disc.
When the sand issues from the upper end of the vertical pipe it will strike any
object that is placed over the hole in the cover of the box, and will cut away the
surface thereof so long as it remains there. The sand after striking the object will
fall down into the box, and will be ultimately deposited at the bottom of the close
cylindrical chamber, from which it may be removed from time to time and replaced
in the sand reservoir above.
The air when it escapes from the vertical tube passes into the close cylindrical
vessel, and from thence up the large inclined air channel or passage, carrying
with it the lighter portions of the sand and dust, which will be deposited
on the inclined bottom of the air channel, from whence it will 'slide down
into the close cylindrical chamber, from whence it may from time to time be
removed.
When it is desired to operate upon large surfaces, as, for instance, on sheet glass,
the apparatus must be modified accordingly, and instead of one small cylindrical
pipe for admitting air to the vacuum chamber, the air passage is made in the form
of a flat long narrow box, at the upper or open end of which is a long narrow slit

page_text: about half an inch wide, which opens into the vacuum box or chest which is made
shallow, and is connected at both sides by means of suitable pipes with inclined air
channels or passages, as in the former case.
The lower part of the narrow air pipe is trumpet-mouthed as before, and the sand
is deposited on a plate, the end of which is curved up, so as to project up into the
trumpet mouth, and as the air rushes into the trumpet mouth it carries with it the
sand which is impelled upwards with considerable velocity, so that on issuing from
the narrow slit, it will strike against any object placed above. For this purpose a
long narrow opening is made in the table immediately above the exit opening, and is
provided with lips to regulate the width of the opening.
The sand after acting on the under side of the glass, as the latter is slowly moved
forward, is carried as before mentioned into the inclined air channels, where it is.
deposited, and slides down from the inclined bottom into a box containing an
archimedian screw, whereby it is carried forward and deposited in regulated
quantities on the curved plate below the trumpet mouth, so that it is worked over.
and over again.
It is scarcely necessary to say that the quantity of sand supplied to the air pipe
This machine is
is regulated by an adjustable device as in the former case.
intended for plain grinding or obscuring sheet glass, as it is made to travel
slowly but at an uniformn speed through the machine, or rather over the long.
open slot.
For ornamenting sheet glass stencils will of course be required, and the machine
must be modified accordingly.
Sheet glass is usually ornamented by repeating a given pattern at regulated
distances apart on the sheet, for which purpose the sheet of glass must be held still
for a few seconds over the stencils (of which there may be any convenient
number arranged in a line) until the sand has acted on the glass at all the
The glass is then moved forward quickly, in order
open parts of the stencil.
to bring another portion of the sheet above the stencils, and so on until the entire
sheet is covered.
In practice it is not found convenient to do all the figures or devices in one line,
at the same time it has been found more convenient to do only every alternate one..
By this means the work is much better done, but the sheet must of course be
passed a second time through the machine, so as to produce the pattern on those
parts which were untouched before.
To complete some patterns it may be necessary to pass the sheet four or more
times through the machine, and also to change the stencil. Moreover, in place of
having a long continuous slot for the passage of the sand up to the sheet, it is
preferred to conduct it up a series of vertical pipes corresponding in number
and size of opening to the number and shape of the pattern to be produced.
In order that the sheet of glass may be moved forward intermittently to the
exact distance required, the machine is provided with dividing mechanism,
which is capable of adjustment, according to the nature of the pattern to be
produced.
The machine for ornamenting table glass, such as tumblers, wine glasses, decanters,
and other hollow vessels, differs from the other machine in the form of some of its
parts, but is the same in principle of construction, inasmuch as the sand is fed on to
a plate, from whence it is carried up a vertical pipe by an ascending current of air.
which is drawn in by an exhausting apparatus. There is also fitted to an opening
in the table or cover of the machine a stencil plate, whereby the pattern is pro-
duced all round the article by turning it round, so as to present in succession fresh
surfaces for the sand to operate against. This stencil plate is mounted in a frame
which is capable of a limited motion on centre pins or equivalent devices in the
hole in the cover or top of the vacuum chamber, so that the curved surface of
the article may be made to fit or adjust itself against the stencil.
The tumbler or glass to be operated upon is temporarily clamped to a spindle
which is capable of rotation on its longitudinal axis, and is provided with a dividing

page_text: plate, so that one complete rotation of the article may be accurately subdivided into
as many parts as may be necessary to complete the pattern all round the article.
To the upper end of the vertical sand and air pipe a tumbling cover is adapted,
which, when the article is removed from the stencil plate, will prevent the sand from
rushing out of the opening.
The last part of the Invention relates to the apparatus for exhausting the air
from the vacuum chamber. This operation has heretofore been effected by means of
a fan rotated at a very high speed, for which purpose a considerable amount of
power is required. It has also been found that the exhausted air carries with it
into the fan case a good deal of fine grit, which, when struck with the fan blades
when travelling at high velocity, will soon cut out and destroy them. To obviate
these difficulties the working parts of my improved exhausting apparatus are so
constructed and arranged that they will be driven at a greatly reduced speed, will
consequently require much less power, and will give better results than an ordinary
rotary fan blower.
My improved exhausting apparatus consists of an air-tight case, in which is
mounted on a suitable shaft a vibrating fan or piston, which is actuated by means of
n crank keyed on the end of the vibrating fan shaft outside the casing, and connected
by means of a rod or link to a shorter crank on a rotating shaft, which is driven by
any prime mover.
It will be understood that as one crank is longer than the other, the shorter,
although kept in constant rotary motion, will only communicate a vibrating motion
to the longer crank, and a corresponding motion to the fan blade, mounted on the
same shaft inside the casing. Below the vibrating fan case is the valve chamber,
which is divided by a vertical partition into two compartments, in one of which are
placed the valves for admitting air to the casing when sucked in by the backward
motion of the vibrating fan blade; and in the other are the valves for the escape of
the air therefrom, when propelled forward by the advance of the fan blade. These
valves are made with a large superficial area, so as to interfere as little as possible
with the passage of the air. They rise but a short distance from their seats, and
they are either weighted or provided with adjustable springs, whereby the pressure
of the air may be regulated.
The two compartments of the valve chest communicate respectively with the
supply and exit air pipes, as will be well understood, and the apparatus may be used
either for exhausting the air from a chamber, or for producing a pressure blast of
air, as may be required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jeremiah Eugene Mathewson in the Great Seal Patent Office on the
27th February 1878.
JEREMIAH EUGENE MATHEWSON, of Gray's Inn Road, in the County of Middle-
sex, Engineer. " IMPROVEMENTS IN APPARATUS FOR DRILLING, GRINDING, OR
OBSCURING AND ORNAMENTING GLASS OR OTHER HARD SUBSTANCES, PARTS
OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES FOR
WHICH A BLAST OF AIR IS REQUIRED, OR FOR EXHAUSTING GASES OR
AERIFORM FLUIDS."
In operating upon the surface of glass, stone, marble, iron, metal, or other hard
substances by means of a blast of sand, for the purpose drilling, grinding, obscuring,
or ornamenting the same, the articles to be operated upon have been usually confined
in a close chamber, and the sand has been impelled with considerable force down-
wards by means of a blast of air that has been driven forward by a fan or blower.
For many articles the machinery or apparatus heretofore employed for operating
with the sand blast in this manner is of a very cumbrous and expensive
character, and great inconvenience has been experienced from the escape from the
close chamber of very fine dust into the room or chamber where the machine is at
work.
The first part of the present Invention has for its object to obviate these incon-
veniences, and to reduce the cost of the apparatus. To this end, instead of forcing
into a close chamber with the sand a plenum of air under pressure as heretofore,
I, by means of an exhausting apparatus, produce a partial vacuum in the close
chamber, and the external air which rushes into this chamber to fill the vacuum is
made to pass up a narrow pipe or channel, and carry with it a regulated quantity of
sand, which is supplied to a trumpet mouth at the lower end of the air pipe or
channel, which is left open for the purpose.
It will of course be understood that apparatus or machines which are required to
act on this principle of suction blast must be specially constructed and arranged
according to the character and form of the articles to be operated upon.
In the accompanying Drawings, Fig. 1, Sheet I., is a partial side elevation of a
machine for grinding or obscuring flat sheets of glass, such as window glass.
Fig. 1, Sheet IV., is a continuation of the same Figure. Fig. 2, Sheet II., is a
partial elevation of one end of the machine. Fig. 3, Sheet II., is a transverse
vertical section of the machine. Fig. 3*, Sheet III., is a view of the settling
chamber, and is in fact a continuation of the view given at Fig. 3. Fig. 4,
Sheet IV., is a longitudinal vertical section of the machine.
In this machine the sheets of glass to be operated upon are placed on a flat table a,
which is provided with a pair of travelling endless chains b, b, which pass round
pairs of chain wheels b', ', at each end of the table. Motion is communicated to
the travelling chains b, b, in the following manner: The main driving shaft c of
the machine carries a pair of fast and loose pullies which receive motion from any
prime mover. The shaft c also carries a cone pulley cl, and by means of a belt c²,
imparts motion to a counter shaft d, the outer end of which carries a worm d', which
gears into a worm wheel e mounted loosely on the shaft be of one of the pairs of
chain wheels b. This worm wheel c carries a pawl which takes into the teeth of a
ratchet wheel, keyed fast on the shaft 62, so that this latter is capable of rotating
independently of the worm wheel in one direction. By this arrangement the chain
can be quickly wound up by means of a winch handle et, and thus caused to travel
forward and bring the sheet of glass up to an open slot in the table.
It will now be understood that by the worin d' actuating the worm wheel e, a
slow progressive or travelling motion will be imparted to the chains b, b, the speed
of which may be regulated by the cone pullies c¹. The chains b, b, are provided with
loose bars 6 (shewn full size at Fig. 5), which catch hold of the sheet of glass and

page_text: carry the same slowly forward on the table a.
About midway from the two ends
of the table, an opening is made in the latter to receive a vacuum box j, in which is
made a long narrow slit, as seen at j. This part of the apparatus is shewn in cross
section at Fig. 4. The size of the long slit or opening in the box j is determined by
two side plates of sheet iron, which are secured in place by screws, and which, when
The outer sides of the box j are
worn away may be easily replaced by new ones.
connected with the horizontal conical pipes j, j³, one end of each of which is closed,
while the other is turned up and terminates in the inclined channel or chamber, j*, j*.
At the centre of the vacuuin box j, and immediately below the long slot, is fixed
the vertical pipe k, Fig. 4, which is made in the form of a long narrow box, with an
opening at the upper end, of the same length as the long narrow slot j¹. A trumpet
mouth k is fitted to the lower end of this pipe k, and a curved guide plate l. is
inserted into the trumpet mouth. The sand is allowed to drop from openings in
the under side of the borizontal pipe m into a funnel or hopper m', from whence it
passes on to the curved plate 1, as shown at Fig. 4. The width of the opening
through through the sand passes is regulated by an adjustable plate n carried by
arms n' on a rocking shaft n² mounted in bearings attached to the main framing
of the machine. The end of this shaft carries a crank handle », which by means of
a spring n' is kept against a stop n³, so that the quantity of sand fed into the machine
can be adjusted with accuracy by means of the adjustable stop n', as will be well
understood.
Should any stoppage in the flow of sand occur, the passage may be instantly cleared
by throwing back the handle n³, and thereby temporarily withdrawing the plate n.
The horizontal pipe m is provided with an archimedean screw m², as indicated by
the dotted lines in Figures 3 and 3* and this screw is actuated by a band m³
passed over a pulley on the end of the screw shaft and driver in any convenient
manner. The outer end of the pipe m is connected by a bent pipe and short vertical
pipe p, with the lower part of the inclined chamber j*, so that as the sand is drawn
with the air from the vacuum box or chamber j into the inclined chamber j*, it will
be deposited therein and will pass down the pipe p into the horizontal pipe m, along
which it will be pushed by the rotation of the screw therein.
As the archimedean screw is kept constantly rotating, it will of course keep the
sand slowly moving forward in the pipe m, and so long as the sand passes through
the funnel into the machine, the apparatus will act properly, but should there
be (from any cause) an accumulation of sand in the funnel m³, so as to prevent
its delivery from the pipe m, while the screw continues to revolve, some part of
the machinery would be subjected to an undue strain and would probably be
put out of order. To prevent this, the driving band m³ (Figures 3ª and 3",
Sheet III.) is tightened on the pullies by means of a weighted lever m³, which will
allow the band m³ to slip on the pulley at the end of the screw shaft, when any
undue strain occurs, so that the screw will remain stationary until the accumulation
of sand is removed.
The under side of that part of the pipe m which is over the hopper m¹ is per-
forated with a series of holes so as to allow the sand to drop from the pipe into the
hopper m², as seen at Fig. 4. and from thence on to the curved plate l, as already
explained, so that as the vacuum is produced in the box j, the external air will rush
into the trumpet mouth of the vertical pipe, and up this pipe into the box j,
carrying with it the sand. The sand being thus propelled forward with force will
pass up through the long slit j¹ and strike against the under side of the sheet of
glass which is being slowly carried forward over the slit by the travelling endless
chains b, b, and all that part of the glass which is thus exposed to the action of the
sand will be obscured or ground.
When sheets of glass of greater width than the length of the slit j¹ are to be
ground a portion only of the surface will be acted on at the first operation, and
therefore in order to grind or obscure the whole surface the sheet must be turned
round and passed a second time through the machine.
In order to prevent the sand from being carried out of the inclined chamber j*

page_text: with the rush of air to the exhausting apparatus, longitudinal and transverse baffle
plates are fitted inside the inclined chamber jo, as indicated by dots in Fig. 3, so as
to arrest the sand, and cause it to fall down on to the inclined bottom of the
chamber, down which it will slide to the lower part, and pass from thence down the
vertical pipe p to the screw pipe m, as already explained.
For ornamenting or producing a pattern on sheet glass, stencils will of course be
required, and the machine must be modified accordingly.
Sheet glass is usually ornamented by repeating a given pattern at regulated
distances apart on the sheet, for which purpose in my improved apparatus the sheet
of glass must be held still for a few seconds over the stencils, of which there may be
any convenient number arranged in a line in or above the long slot 71. The sheet
of glass remains stationary for a few seconds until the sand has acted on the glass
at all the open parts of the stencil; the glass is then moved forward quickly in
order to bring another portion of the sheet above the stencils, and so on until the
entire sheet is covered.
In practice it is not found convenient to do all the figures or devices in one line
at the same time; it has been found more convenient to do only every alternate one.
By this means the work is much better done, but the sheet must of course be passed
a second time through the machine, so as to produce the pattern on those parts
which were untouched before.
To complete some patterns it may be necessary to pass the sheet four or more
times through the machine, and also to change the stencil. For producing patterns
in this manner the sheet of glass may be moved forward intermittently by hand, or
an intermittent motion may be given to the travelling chain b, b, the extent of
motion of course depending on the nature of the pattern. In place of having a
long continuous slot for the passage of the sand up to the sheet it is preferred when
the machine is used for producing a pattern or ornament on the glass to
conduct it up a series of vertical pipes corresponding in number and size of opening
to the number of repetitions in one transverse line and the shape of the pattern to
be produced.
In order that the sheet of glass may be moved forward intermittently to the exact
distance required the machine is provided with dividing mechanism, which is capable
of adjustment, according to the nature of the pattern to be produced.
This dividing mechanism is adapted to the gearing which actuates the travelling
endless chains, as will be well understood.
This apparatus may also be used for drilling holes in sheet glass for window
ventilators or other purposes. For window ventilators it is usual to make a series
of holes in a line across the sheet of glass, or there may be two or more lines of
holes.
For the purpose of drilling these holes, instead of the long narrow tube box j', I
employ a series of round pipes placed vertically below the slot in the table, and
arranged in a line just in the manner already explained for ornamenting the sheet
glass. In the slot in the table are placed metal stencil plates, with holes of the
shape and size required to be made in the glass. The sand is sucked up the vertical
pipes in the way already explained, and strikes through the holes in the stencil
plates against the glass, which is quickly cut away by the sand, and clean holes are
thereby drilled through the glass.
It will of course be understood that all the holes in one line across the glass. are
drilled simultaneously, or nearly so, but as it is found in practice that all the holes
are not completed exactly at the same moment care must be taken not to allow air
to rush into the vacuum chamber through the hole that is first made, otherwise it
will interfere with the operation of completing the others. This is easily done by
placing over the holes (immediately any opening is made by the sand completely
through the glass) a piece of sheet rubber, which will be held down by the suction,
and will keep the apparatus air-tight until all the holes in one series are completed.
When one series of holes has been made the sheet of glass may be moved rapidly
forward, so as to bring another portion of the sheet above the holes in the stencil

page_text: plates, and then a second row of holes may be drilled, and so on for as many rows
of holes as may be required. In this way any number of holes of any desired shape
may be drilled in a sheet of glass without the smallest risk of breaking the glass
during the operation.
If single holes only are required to be drilled in pieces of glass, or countersunk
recesses, or cells in glass slides for microscopical objects, a simpler, smaller, and less
expensive apparatus may be employed, such as that shown in Sheet V., in which
Fig. 5 is a side elevation of the machine; and Fig. 6, a front elevation.
Fig. 7 is a vertical section of the small vacuum chamber j, containing the air
pipek, below the lower open end of which is placed the flat circular plate l mounted
on the bracket 1, which is adjustable vertically. The sand from any convenient
vessel or reservoir placed above, but not shown in the Drawing, passes over the
pipe m, and falls into the plate from a spout at the lower end of the pipe m, the
exit aperture of which is adjustable, as shown in the detached sectional view, Fig. 8.
At the centre of the circular top of the vacuum chamber ; is made a circular hole j¹,
in which is fitted a circular disc or ring of soft sheet rubber to form a bed to receive
a circular stencil plate, as seen in the detached plan view, Fig. 9. This plate is
made with a circular hole in it of the size of the hole intended to be made in the
glass. Upon creating a partial vacuum in the large chamber *, with which the
chamber is connected, air will rush up the pipe k, and will carry with it any sand
that is allowed to drop from the sand pipe m on to the circular plate 1, and will
cause the sand to strike against a piece of glass or other substance that is placed
over and upon the opening ; in the top or cover of the chamber j, and if the piece
of glass be allowed to remain there a minute or two a hole will be either drilled
completely through it, or a cell or countersunk recess will be made, such as those
used to receive microscopic objects.
The machine or apparatus used for producing the vacuum in the machine above
described is shewn in Sheets VI., VII., and VIII, in which Fig. 10, Sheet VI., is a
side elevation of the machine, showing the mode of actuating the working parts
Fig. 11 is a plan view of the machine.
Fig. 12 is another plan view, showing the interior of the machine, the segmental
cover of the air chamber and the vibrating piston having been removed in order to
show the arrangement of the valves for admitting the air to and discharging it from
the air chamber.
Fig. 13, Sheet VII., is a longitudinal vertical section taken in the line A, B, of
Fig. 12, through the eduction valves; and Fig. 14, Sheet VII., is a similar view
taken in the line C, D, of Fig. 12, through the induction valves.
Fig. 15, VII., is a transverse vertical section taken through the centre of
the machine.
In the several Figures u, u, is the air chamber constructed in the form of a
section of about one-third of a cylinder, with solid ends and a sheet-iron cover.
The ends or sides of this chamber are made of cast iron, and are provided with
bearings to carry the rocking shaft on which the vibrating fan or piston is mounted.
Inside this chamber is mounted in suitable bearings a shaft v, which extends
through the bearings in the vertical ends of the chamber, and carries externally a
crank v², connected by rods with a crank pin v³ on a disc or wheel v, to which
rotary motion is imparted from any prime mover. As the length of the crank v¹,
Fig. 10, exceeds the distance of the crank pin from the centre of the disc, it
follows that although the smaller crank will perform complete revolutions it will
only impart to the longer crank v part of a revolution, and that consequently the
latter, with its shaft, will have a reciprocating, oscillating, or rocking motion imparted
to it.
Referring now again to Figures 13, 14, and 15, will be seen that on the hollow shaft
vis mounted a light frame, which carries a rectangular piece of sheet iron, so
that this frame with its sheet iron will form a reciprocating fan blade or piston,
which vibrates to and fro in the chamber u. This vibrating frame is accurately
fitted to work in the chamber with as little space as possible between the two

page_text: parts, but so that the parts do not touch. Immediately below the chamber u are
the valve chambers w², w³, which are separated from each other by a fixed vertical
partition wl (Fig. 15) so as to forin two chainbers or compartments w², and w³, one
to receive the inlet valves x, shown at Fig. 14, and the other, the outlet valves x¹,
shown at Fig. 13. These valves are made of considerable size, and are separately
carried and kept down on their seats by a pair of coiled springs. The ends of each
pair of the valve springs are coiled round and made fast to a squared rod, which
passes through a Y shaped frame x2 bolted to the under side of the valve seat. By
turning these rods the pressure of the springs of the valves can be adjusted with
facility and great accuracy, so that they may be made to open at very slight
pressure.
It will now be understood that as the shaft v, with its light fan blade or piston v³,
is vibrated in the direction of the arrow in Fig. 14, air will be drawn into the
chamber through the pipe y and right-band valves x, as indicated by the arrow,
and as the frame or piston advances the air in front of the piston will be driven
out through the left-hand set of exit valves, Fig. 13, into the other compartment
w² of the valve chamber, and will pass out of the valve chamber w² and exit pipe z,
as indicated by the arrow. On the return stroke of the piston 5 the air will be
drawn from the valve chamber w³ through the left-hand set of valves x (Fig. 14),
and the air in front of the piston on its return stroke will be forced through the
right-hand exit valves x into the other valve chamber w², and from thence through
the exit pipe z, as before, in a nearly continuous stream, and at an uniform pressure.
By this mode of constructing, arranging, and operating the valves, the latter will
have a nearly perfect parallel motion, and although their action will be very slight
and noiseless, they will allow the air to pass freely. It will be obvious that this
apparatus may be used either as an air exhauster or as a pressure blower, and that
the pressure may be regulated by adjusting the tension of the springs which carry
the valves.
It will also be found particularly useful for exhausting or drawing off gases or
aeriform fluids, as it will work equally well whether driven fast or more slowly.
Although I have described the best form of valve for exhausting air for sand
blast purposes, it will be evident that the construction of these parts may be varied
without departing from my Invention.
Figures 16, 17, 18, and 19 represent various views of a modification of the appa-
ratus just described, the principal difference being in the arrangement of the valves
and in placing the valve springs which carry the valves inside the air chamber u,
instead of in the chambers beneath, as in the former instance. This arrangement is
intended to act only as a pressure blower, the air being drawn in from the external
atmosphere through the outermost valves into the air chamber u, and forced out
from the latter through the innermost or exit valves into the exit passage . If,
however, it be desired to use this arrangement of valves in an exhausting apparatus,
the machine may be converted into an exhauster by enclosing the space below the
valves, as indicated by the dotted lines in Fig. 17.
I would here remark that owing to the great capacity of my improved exhausting
and blowing apparatus, and the large area of the valve openings, I am enabled to
obtain a large volume of air at a moderately good pressure, without driving it at a
high speed, which would require a considerable amount of power. For instance I
have found in practice that in order to obtain anything like an effective exhaust
with fans of the most approved construction it is necessary to drive at a speed of
more than three thousand revolutions per minute, whereas I find that with my
apparatus above described I can obtain a sufficient vacuum by driving the working
shaft a little over one hundred revolutions per minute, thereby greatly reducing the
amount of power required, and vastly diminishing the wear and tear of the
machinery.
Having now described my Invention, and having explained the manner of
carrying the same into effect, I claim as the Invention secured to me by Letters
Patent as aforesaid :—

page_text: First. The general construction and arrangement of parts herein shown and
described for drilling, grinding, obscuring and ornamenting glass or other hard
substances. I claim particularly the combination of the flat table a with the
travelling endless chains or their equivalent for carrying forward the glass or other
hard substance, such table being provided with a long narrow slit or opening, or
with a series of openings through which a stream or streams of sand is or are pro-
pelled and caused to strike the under side of the glass or other hard substance by
being carried up a pipe or pipes by the rush of ascending currents of air induced by
a partial vacuum produced in a chamber below the slit or opening in the table by
any suitable air-exhausting apparatus.
Second. I claim the construction and arrangement parts herein shewn and
described, and constituting my improved apparatus for exhausting or blowing air
as and for the purposes herein set forth.
I also claim the application of my improved exhausting apparatus for
exhausting or drawing off gases or aeriform fluids.
In witness whereof, I, the said Jeremiah Eugene Mathewson have hereunto
set my hand and seal, the Twenty-seventh day of February, in the year
of our Lord One thousand eight hundred and seventy-eight.