Improvements in Pneumatic Tools for Hand or other Use for Chipping, Caulking, and like Operations.
Year: 1899

page_text: Date of Application, 24th Aug., 1899 -Accepted, 6th Jan,, 1900
COMPLETE SPECIFICATION.
Improvements in Pneumatic Tools for Hand or other Use for Chipping,
Caulking, and like Operations.
I, GLENN BURGESS HARRIS, of No. 318, West Seymour Street, Philadelphia,
County of Philadelphia and State of Pennsylvania, United States of America,
Gentleman, do hereby declare the nature of my invention, and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
My invention relates to a pneumatic tool that is especially designed for
chipping, and calking metal; but may be used for any purpose for which pneu-
matic tools are ordinarily employed. The object of the invention is to provide
a new form of valved tool, wherein the piston or striker operates by its reciproca-
tion to alternately admit, and exhaust air at only one end of the valve, and
wherein the passages between the valve and piston, and the passages connecting
the supply and exhaust with the valve and piston are so arranged as to secure a
smooth and satisfactory operation of the tool, with a minimum of vibration,
and a maximum of power. The invention consists of an arrangement of valve,
piston, ports and passages designed to carry out this object, and it also consists
of a new construction of valve, and of novel means for locking the separate
parts of the tool together, and for accurately adjusting the handle with respect
to the casing when the bearing or contact surfaces between the two become worn
and loose by reason of prolonged use. The invention also consists of minor
details of construction which will be hereinafter fully set forth.
line
In the drawings, Figure 1 is a longitudinal section on line 11, Figure 3;
Figure is
through
longitudinal section
22, Figure 3;
Figure 3 is a transverse section through line 33, Figure 1; Figure 4 is a
transverse section through line 4 4, Figure 1; Figures 5, 6, 7 and 8 are longi-
tudinal sectional diagrams, illustrating the respective positions of piston and
valve, and the ports and passages through which they communicate respectively
with the supply or exhaust throughout the cycle of movements of the moving
parts.
The casing for the ports and passages and the moving parts comprises a piston
cylinder, valve casing and handle.
A is the cylinder for the piston. B is a valve casing, C is a retaining piece
for the valve casing and constitutes, in effect, a part thereof. Dis the handle
which is provided with a depending annular Hange, screw threaded at its
extremity and engaging a thread at the upper end of the cylinder. Through the
retaining piece C, valve casing B and cylinder A extend pins s which serve to
hold these parts in proper relation to each other and ensure accurate alignment
of the passages. By screwing the handle D, upon the cylinder and down upon
the retaining piece, the cylinder, valve casing, retaining piece and handle are
brought into firm contact with each other.
At the lower end of the cylinder is a bushing e surrounding the end
of the chisel E, which, in operation is struck by the piston or striker A in (be

page_text: cylinder A. The piston is provided with an annular recess b, the purpose of
which will be hereinafter described. Within the valve casing is a hollow
valve C comprising a cylindrical portion having an annular shouldered pro
jection e at the bottom thereof and another annular projection c¹ of greater radial
extent between its ends. The valve casing is cut away to form a chamber
between the valve and casing. In this chamber the projecting part c¹ of the valve
reciprocates. Another annular chamber y is formed between the annular end of
the handle and the exterior of the valve casing.
Within the handle D is a passage a, adapted to be connected directly with
the supply by means to be hereinafter described, and communicating with the
interior of the hollow valve. Through the bottom of the valve casing, which
separates the valve chamber from the piston chamber, is a port a¹, by means
of which the pressure fluid is admitted to.the upper end of the piston chamber
when the valve is raised. X2 is a passage extending through the retaining piece,
main valve casing, and cylinder, and having ports 21, and, adapted to com-
municate respectively with the upper end of the valve chamber, and the lower
end of the piston chamber, by which the fluid pressure is admitted to the lower
end of the piston chamber when the valve is in its lowest position. This
passage also has a port, communicating with the lower part of the chamber y.
is a passage extending through the cylinder and valve casing, having at one
end a port that communicates with the interior of the valve casing, and at
the other end a port communicating with the piston chamber. is a
passage extending through the cylinder and valve casing, having at one end a
port communicating with the upper end of the chamber y, and toward the
other end ports 2 and 3 communicating with the piston chamber. is a
passage extending through the cylinder and valve casing, one end communicating
with chamber y and the other end with the piston chamber. is an exhaust
port leading from chamber y'. is a passage connecting chambers y and y¹.
At the upper end of the handle is formed a chamber y, having a
threaded orifice adapted to receive a pipe connected with a source of fluid
pressure. Carried by the handle and extending through chamber y³, is a bush-
ing F, having orifices f, communicating with chamber y, and an orifice f¹
communicating with passage a.
screw
Extending through the bushing is a valve F, which is held in such position
by means of a compression spring F2, as to close orifice f¹. Pivoted to the handle
is a lever F3, having projection 1, engaging the end of valve F. When the
handle is grasped, this lever will be depressed, causing the valve to be forced in
against the action of the spring F, and admitting the pressure fluid from
chamber y, through orifices f, bushing, orifices f', and passager, to the interior
of the valve chamber.
The pressure fluid being thus admitted to the interior of the valve, the opera-
tion is as follows.
In Figures 5, 6, 7, and 8 the double headed arrows indicate the direction of
flow of the supply fluid, while the single headed arrows indicate the path for
the exhaust.
Assuming the piston and valve to be in the position shown in Figures 1, 2,
and 5, the pressure fluid passes through porta into the top of the piston chamber,
while the air is exhausted from beneath the piston through passage, chambery,
passage, chamber y', and exhaust port. The exhaust also takes place to some
extent through passage chamber y and exhaust port. The valve is main-
tained in its upper positions by reason of the constant pressure against the lower sur-
face €, of the valve, and by reason of the upper and lower surfaces of the
annular projection , being in communication with the exhaust. The piston,
however, will be moved down into the position shown in Figure 6.
When the piston is at the lower end of the cylinder, the valve is shifted down
by the admission of the pressure fluid to chamber y, against the upper surface of
projection by passing through the hollow valve, passage ³, around the recess b,

page_text: in the piston, passage a¹ and port, causing the pressure against the top of pro-
jection c, to overbalance the constant pressure against the lower end of the
valve, the lower surface of projection being in constant communication with
the exhaust. The valve is thus shifted into the position shown in Figure 7.
When the valve is thus shifted, the pressure fluid will pass through port,
passage, and port to the lower end of the piston chamber,
while the air above the piston will exhaust through port, chamber y,
port chamber y', and port, causing the piston to move up into
the position shown in Figure 8. Upon the shifting of the piston just described,
the top of projection el, is connected with the exhaust through passage, lower
part of cylinder, passage, chamber y and port and the constant pressure
against the bottom of the valve will move the valve to shift up into the position
shown in Figure 5.
The periphery of the valve retaining piece C, is provided with a ratchet g.
In the depending end of the handle 1), is formed, immediately opposite the
retaining piece C, a hollow lug g, which forms the bearing for the head of
sliding pawl or pin 2, having an L-shaped extension g³, one arm of which
extends through a bearing g within the hollow lug g', while the other armi
extends down between and beyond the flanges of lug near the end thereof. The
inner end of the pin has a projection ", which normally engages the teeth of
the ratchet, being forced into engagement therewith by a spring placed
between the bearing g, and the enlarged head of the pin. When it is desired
to take the tool apart, the pin is pulled outward to disengage the pin and ratchet,
and given a quarter turn so that when released the extension g' will rest against
the flanges of lug g', whereby the pin and ratchet will be held out of engagement
to permit the tool to be taken apart. If owing to wear, the bearing between
the cylinder and valve, or the valve and retaining piece and handle becomes loose,
it may be tightened by turning the handle to slide over one or more teeth of
the ratchet.
This pin and ratchet construction, of course, serves to prevent the handle from
turning except in a direction to tighten the connection between the parts.
The projection on the valve may obviously be formed by making the valve in
the shape of a shell of uniform thickness, the only requirement being that
provision shall be made for the differential pressure surfaces as described.
It will be observed that the hollow valve is constantly in connection with
the supply and constitutes, in effect, a reservoir of pressure fluid, the air there-
from being admitted directly to either side of the piston by the shifting of the
valve. When the valve moves down, the pressure fluid passes through passage
to the lower part of the piston chamber, and when the valve moves up, the pressure
fluid passes through port ¹, to the upper part of the piston chamber. Thus
I dispense with the necessity of carrying the air through any chamber between
the valve and its casing.
It will also be observed that the air is exhausted from beneath and from above
the piston chamber directly into that part of the chamber y, which is in constant
communication with the exhaust.
There is but one chamber between the valve and its casing, namely, the
chamber y, the portion thereof beneath the annular projection, being in
constant communication with the exhaust and through which the air is exhausted
from beneath the piston, while the upper surface is in communication with the
supply only when the piston is at the lower end of the stroke, the trapped air
therein, however, serving to hold the valve in its lower position until the piston
has moved up beyond the port.
The air is admitted to and exhausted from the top of the annular projection c¹,
through one and the same passage, namely, passage, the passage being brought
alternately into communication with the supply and exhaust through ports 3,
and 3, respectively.
The valve and piston are so constructed and the ports and passages so arranged

page_text: that the upward movement of the piston will move the valve up, and a downward
movement of the piston will move the valve down.
The weight of the piston may be increased by boring out the piston as shown
in dotted lines in Figures 1 and 2, and filling the same with lead or other heavy
metal, and plugging up the end by a plug or cap m. By this means with a tool
of any specified size, I get a piston of greater weight, and hence greater striking
force for a given length and area than heretofore, as I am enabled to use lead
or other heavy metal which would not be available as a material for the whole
piston.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is::
1. In a pneumatic tool, the combination of a valve and piston and a casing
therefor, there being an inlet in the casing for the supply, the valve being hollow
and the valve chamber within the valve being in constant communication with
the inlet, the casing having ports and passages in proximity to the upper and
lower ends of the valve chamber respectively, and connected directly with opposite
ends of the piston chamber and adapted to be brought alternately into communica-
tion with the valve chamber by the reciprocation of the valve.
2. In a pneumatic tool, the combination of a valve and piston and a casing
therefor, there being an inlet in the casing for the supply, the valve being
hollow and the valve chamber within the valve being in constant communication
with the inlet, the casing having ports and passages in proximity to the upper
and lower ends of the valve chamber respectively, and connected directly with
opposite ends of the piston chamber and adapted to be brought alternately into
communication with the valve chamber by the reciprocation of the valve, the
said valve also having projections of differential area, a chamber between the
valve and the casing adapted to the reception of the projection of larger area, a
passage communicating with said chamber on one side of said projection, and
ports and passages controlled by the piston in its reciprocation to alternately
connect said passages to the chamber with the supply and exhaust, and a passage
communicating with said chamber on the other side of said projection în con-
nection with the exhaust.
3. In a pneumatic tool, the combination of a valve and piston and a casing
therefor, the said valve having projections having differential pressure surfaces,
a chamber between the valve and the casing adapted to the reception of the
projection having the pressure surface of larger area, an exhaust passage con-
stantly connected with the chamber on one side of said projection, and passages
leading from the opposite ends of the piston cylinder arranged to be alternately
connected with the chamber on the exhaust side of said projection by the shifting
of the valve, whereby the exhaust from each end of said piston passes to that
part of the chamber in constant communication with the exhaust and thence
through said exhaust passage.
4. In a pneumatic tool the combination with the casing of a valve having
projections of differential areas, a chamber between the valve and the casing
adapted to the reception of the projection of larger area, a piston having an
annular groove, a main inlet port, a passage communicating therewith adapted
to register with said groove when the piston is at one end of its stroke, a second
passage adapted to register with said groove at the same time and communicating
with the said chamber on one side of said projection, an exhaust passage con-
stantly connected with the chamber on the other side of said piston, and passages
leading from the ends of the piston cylinder arranged to be alternately con-
nected with the chamber on the exhaust side of said projection by the shifting
of the valve, whereby the exhaust from each end of the piston passes to that
part of the chamber in constant communication with the exhaust, and thence
through said exhaust passage.

page_text: 5. In a pneumatic tool, the combination with the casing of a valve having
projections of differential area, a chamber between the valve and the casing
adapted to the reception of the projection of larger area, a piston having an
annular groove, a main inlet, a passage communicating therewith having a port
adapted to register with said groove when the piston is at one end of its stroke,
a second passage communicating with the exhaust and having a port leading to
the piston chamber adapted to be opened by said piston when at the other end
of its stroke, a third passage communicating with said chamber on one side of
said projection, said passage having two ports, one adapted to register with said
groove when the piston is at one end of its stroke, the other leading to the
piston chamber adapted to be opened by said piston when at the other end of
its stroke, whereby the said chamber between valve and casing will be con-
nected alternately with supply and exhaust by the shifting of the piston.
6. In a pneumatic tool, the combination with the piston and casing, of a valve
having projections of differential areas, a chamber between the valve and the
casing adapted to the reception of the projection of larger area, a passage
communicating with said chamber on one side of said projection and with the
piston chamber, and a supply passage and an exhaust passage also in com-
munication with the piston chamber and controlled by the piston in its reciproca-
tion to alternately connect the first named passage with the supply and exhaust.
7. In a pneumatic tool, the combination of a valve and piston and a casing therefor
there being an inlet in the casing for the supply, the valve being hollow and the
valve chamber within the valve being in constant communication with the inlet,
the casing having ports and passages in proximity to the upper and lower ends
of the valve chamber respectively, and connected directly with opposite ends of
the piston chamber and adapted to be brought alternately into communication
with the valve chamber by the reciprocation of the valve, the said valve also
having projections of differential area, a chamber between the valve and the
casing adapted to the reception of the projection of larger area, a passage' com-
municating with said chamber on one side of said projection, and ports and
passages constrolled by the piston in its reciprocation to alternately connect said
passage to the chamber with the supply and exhaust, and a passage communicat-
ing with said chamber on the other side of said projection in connection with
the exhaust, said passages communicating with said chamber on opposite sides
of said projection being in proximity respectively to the upper and lower ends of
the valve and connected with opposite ends of the piston chamber.
8. A weighted piston for pneumatic tools, having its side and striking end of
one metal and a core of metal of higher specific gravity than the sides and
striking end.
9. The combination with the valve casing consisting of the main body thereof
and the retaining piece, the latter having a ratchet on its periphery and being
removably secured to the main body of the casing, of a handle having a depend-
ing annular flange surrounding the retaining piece, and a sliding pawl in said
flange and engaging said ratchet.
10. The combination with the valve casing consisting of the main body thereof
and the retaining piece, the latter having a ratchet on its periphery and being
removably secured to the main body of the casing, of a handle having a depend-
ing annular flange surrounding the retaining piece, a pawl in a hollow portion of
said handle flange and engaging said ratchet, said pawl being spring pressed
against the ratchet and having an L-shaped extension piece to permit the with-
drawal by hand of the pawl from engagement with the ratchet.
11. The combination with the valve casing consisting of the main body thereof
and the retaining piece, the latter having a ratchet on its periphery and being
removably secured to the main body of the casing, of a handle having a depend-
ing annular flange surrounding the retaining piece, a pawl in a hollow portion
of said handle flange and engaging said ratchet, said pawl being spring pressed
against the ratchet, and having an extension piece projecting between the walls

page_text: of said hollow portion of the handle flange and adapted to be withdrawn to
engage the exterior of the handle flange, whereby the pawl is held out of engage-
ment with said ratchet.
Dated this 24th day of August 1899.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant