Improvements in Pneumatic Hammers for Chipping and like Operations.
Year: 1899

page_text: Date of Application, 24th Oct., 1899-Accepted, 10th Mar., 1900
COMPLETE SPECIFICATION.
Improvements in Pneumatic Hammers for Chipping and like
Operations.
We, BURT EUGENE TILDEN, Manufacturer, of No. 252, Dearborn Street, and
ROBERT BURNS, Mechanical Engineer, of 112, Randolp Street, both of the City of
Chicago, in the County of Cook and State of Illinois, United States of America,
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the follow-
ing statement:-
The present invention relates to that type of pneumatic engines in which the
reciprocating piston constitutes a hammer adapted to deliver a series of rapidly
recurring blows to a chipping or other tool, the shank of which is located in the
path of such impact piston, and constitutes an end closure for the lower piston
chamber.
The objects of the present improvements are:.
First, to provide a simple and efficient sectional formation and arrangement
of the main cylinder for the impact piston, and the valve block and housing for
the reversing valve, which permits of a ready and convenient detachment of the
parts for cleaning, repair and replacement of worn parts.
Second, to provide means for connecting the handle, main cylinder and valve
block and housing together in a rigid and substantial manner.
Third, to provide means, self contained within the hammer for the automatic
lubrication of the hammer parts while in operation.
We attain such objects by the construction and arrangement of parts illus-
trated in the accompanying drawings, in which,
Figure 1, is a longitudinal elevation at line, Figure 3, illustrating the
position of the parts at the commencement of the forward stroke of the impact
piston of the present pneumatic hammer.
Figure 2, a fragmentary longitudinal section, at line 1-1, Figure 3, illus-
trating the position of the parts at the ending of such forward stroke of the
impact piston and with the valve reversed to effect a backward or return move-
ment of such piston.
Figure 3, a horizontal section at line 2-2, Figures 1 and 2.
Figure 4, a side elevation of the valve block in a detached condition.
Figure 5, a side elevation of the reversing valve in a detached condition.
Similar numerals of reference indicate like parts in the several views.
Referring to the drawings:
1, represents the main cylinder or casing the lower end of which is provided
with a guide bushing 2, that receives the shank portion of the chipping or other
tool, as usual in the present type of.hammers.

page_text: 3, is the cylindrical impact piston adapted to have reciprocating movement in
the bore of the main cylinder 1, and formed with an annular recess or chamber 4,
near its upper end.
Such piston is also provided with reduced axially arranged end extensions 5,
and 6; the lower extension 5, constituting the impact portion of the piston to
impact upon the shank of the chipping or other tool employed, while the upper
extension 6, is adapted to enter a central chamber in the valve block of the
hammer to effect a cushioning action upon the piston as it nears the end of its
upward or return stroke.
Such piston is also formed with a port or passage 7, connecting the annular
passage or chamber 4, of the piston with the lower piston chamber as illustrated
in Figure 2.
8, is the circularly enlarged base of the valve block of the present invention,
which constitutes a head for closing the upper end of the main cylinder 1, and
offsetted to fit the same as illustrated in Figures 1 and 2.
9, is an axially arranged hollow cylindrical portion of the valve block, closed at
its upper end and open at its lower end to form an axially arranged chamber adapted
to receive the upper cylindrical extension 6, of the impact piston as heretofore
described.
10, is the cylindrical valve housing arranged concentrically to the cylindrical
portion 9, of the valve block, and offsetted or counterbored, to form in connection
with such valve block, upper and lower valve chambers 11 and 12, of differential
areas: the upper one of said chamber having an area smaller than the lower one
as shown.
Said valve housing 10, is preferably of an external diameter equal to that of
the main cylinder 1, and fits against the offsetted upper end of the enlarged base 8,
of the valve block as shown.
13, is the reversing valve of an annular form with an internal diameter equal
to the external diameter of the cylindrical portion 9, of the valve block, and
adapted to have its seat thereon.
The lower portion of the valve 13, is formed by an enlarged head 14, that has
movement in the lower enlarged valve chamber 12, while the upper and main
portion of the valve is of a lesser diameter and is adapted to have movement in
the correspondingly reduced upper valve chamber 11.
As so constructed the reversing valve is of a differential nature having differen-
tial pressure areas on its opposite faces and adapted to operate under differential
effects of fluid pressure, as usual in the present type of reversing valve, and the
arrangement is such that the motive fluid will exert constant pressure upon the
upper and smaller area of the valve.
15, is an annular internal exhaust chamber in the main portion of the revers-
ing valve 13; and 16, are openings through the wall of such chamber, the
chamber and openings being adapted to control communication between the
upper and lower piston chambers of the main cylinder and the exhaust port 17,
in the valve housing 10, that opens to the atmosphere as shown in Figures 1, 2
and 3.
18, is a longitudinal port or passage formed in the main cylinder 1, the valve
block head 8, and valve housing 10, the upper end of which has connection with
the lower end of the enlarged lower valve chamber 12, while its extreme lower
end opens into the interior of the main cylinder 1, at a point that will permit
of an exhaust of the motive fluid from the lower valve chamber 12, when the
impact piston 3, is in its upper position as illustrated in Figure 1.
20, is a longitudinal port or passage formed, like the port or passage 18, in
the main cylinder 1, the valve block head 8, and the valve housing 10, with its
upper end communicating with the pressure supply chamber at the upper end of
the hammer, while its lower end communicates with the interior of the main
cylinder 1, at a point opposite the small lateral branch 19, of the longitudinal
passage 18, heretofore described, the arrangement being such that as the annular

page_text: peripherial chamber 4, of the impact piston, uncovers said passages, to put the
same into communication, the fluid pressure will be introduced into the lower
valve chamber 12, to force the reversing valve 13, into its upper position as
indicated in Figure 2; at the same time a restricted supply of motive fluid is
admitted into the lower piston chamber through the port or passage 7, to effect
an upward or return movement of the impact piston 3.
21, are. one or more ports or passages through the upper end of the cylindrical
portion 9, of the valve block and in the path of the upper end of the reversing
valve 13, and through which motive fluid is admitted to the upper piston chamber
in a controllable manner.
22, is a relief or exhaust port or passage formed in the main cylinder 1, the
valve block base 8, and valve housing 10, and connecting the lower piston
chamber with the atmosphere in a controllable manner; its lower end communi-
cating with the lower end of the lower piston chamber, while its upper end opens
into the reversing valve chamber at a point adjacent to the exhaust chamber 15,
of the main reversing valve; so that with the parts in the position illustrated in
Figure 1, the port or passage 22, will be in communication with the atmos-
phere through the exhaust chamber 15, and openings 16, of the reversing valve;
and with the parts in the position illustrated in Figure 2, exhaust nature of
the passage 22, will be rendered inactive by the lower enlarged head 14, of the
reversing valve closing communication between said passage and the exhaust
chamber of the valve.
23, is the attaching sleeve or hub of the hammer handle fitting over the valve
housing 10, the valve block base 8, and the circular flange 24, on the upper end
of the main cylinder 1; the bore of such hub or sleeve being formed with annular
offsets to engage the upper marginal edges of the valve housing 10; and the
valve block base 8, and hold the same in proper relative position.
The extreme lower end of the sleeve or hub 23, is internally screw threaded to
receive the annular nut 25, that has engagement against the under side of the
Hange 24 of the main cylinder, as shown in Figures 1 and 2; the construction
being such that said nut is adapted to forcibly clamp and hold the main cylinder,
valve block and valve housing in proper relative position.
26, is a transverse locking bolt passing through ears 27, that are located on
either side of a vertical slit 28, in the lower end of the sleeve or hub 22 of the
hammer handle, the construction being such as to afford a substantial means for
contracting the lower end of said sleeve upon the annular nut 25, after an adjust-
ment has been attained, and prevent a jarring loose of the parts in use.
29, is the supply passage for the motive fluid, formed in one of the branches 30,
of the hammer handle, and communicating at its lower end with the main supply
chamber 31, at the upper end of the hammer, while its upper end is intersected
by the casing 32, of the manually actuated controlling valve 33.
In the construction illustrated in Figure 1, the valve 33 is of the reciprocat-
ing piston type, formed with an annular peripherial passage or chamber 34,
adapted to register with oppositely arranged orifices 35, in the stationary valve
casing 32, and by its movement to control the supply of motive fluid to the
hammer mechanism:
36, is a spring tending to hold the valve 33 in its closed condition.
37, is a pivoted trigger or thumb lever having engagement with one end of the
valve, and adapted to impart an opening movement to the same.
In the present invention the shank portion of the valve 33, is of an enlarged
formation, that is chambered out to constitute an oil chamber or reservoir 38, the
filling opening of which extends out through the forward end of the valve and
is closed by a screw threaded bolt or stopper 39 as shown in Figure 1, so as to
afford à convenient means for filling the oil reservoir.
40, is the oil feeding orifice from the reservoir, located in the sunken wall of
the annular passage 34, of the valve, which orifice is controlled by an needle
valve 41, also arranged in such cavity or passage 34; with the described con-

page_text: struction the oil will feed from the orifice 40 into the annular passage 34, directly
in the path of the incoming motive fluid, so as to be carried by the same directly
to the various moving parts of the hammer to effect a very perfect and efficient
.lubrication of the same.
The operation of the present hammer mechanism is as follows:
Starting with the parts in the position illustrated in Figure 1,. the motive fluid
from the main supply chamber 31, passes through the ports 21 into the valve
block chamber to press upon the upper end extension 6, of the impact piston 3,
and acting against the decreased area thereof imparts a light initial movement
to the piston which from practical experience is found to be very efficient in
reducing the amount of jar or vibration that is usual in the present type of
hammers. With the end extension 6, of the impact piston forced out of the
chamber of the valve block, the full area of the piston is exposed to the motive
fluid and an active and forcible downward movement of the piston
takes place. In such downward movement of the piston the pressure
of the motive fluid continues until the annular chamber: 4 of the piston registers
the port or passage 20, with the opening 19 of the port or passage 18, after which
the remainder of the active stroke of the piston is dependant upon its momentum.
With the port or passage 20, and opening 19 in communication by means of
the annular passage 4, of the piston, the motive fluid pressure is admitted to the
lower enlarged valve chamber 12, against the enlarged head 14, of: the reversing
valve, to force said valve into its upper position as indicated in Figure 2; to cut
off the supply of motive fluid to the upper piston chamber through ports 21, and
by means of its exhaust chamber 15 and; openings 16, establish communication
between the upper piston chamber and the exhaust port 17 to the atmosphere.
At the same time motive fluid passes down through the restricted port or
passage 7 in the piston into the lower piston chamber, to cause a comparatively
slow return or upward movement of the piston.
With the return of the piston to its upper position, the lower end of the port
or passage 18, is uncovered, and communication between the same and the lower
piston chamber is established, as illustrated in Figure 1, which allows the pressure
in the lower valve chamber 12, to exhaust therefrom, and permit the constant
fluid pressure upon the upper and reduced end of the valve to again force the
same into its lower position, to recommence a fresh cycle of the operations just
described.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, we declare what
we claim, is:-
1. In a pneumatic hammer, the combination of a piston, a piston cylinder, a
valve block closing the end of such cylinder and provided with a hollow cylin-
drical extension forming a valve seat, a valve housing, and a fluid actuated valve
, surrounding said valve seat and having differential pressure areas the reduced
pressure area of the valve being under constant motive fluid pressure, and the
larger pressure area of the valve under an intermittent motive fluid. pressure,
substantially as set forth.
2. In a pneumatic hammer, the combination of a piston, a piston cylinder, a
valve block closing the end of such cylinder and provided with a hollow cylin-
drical extension forming a valve seat, a valve housing, a fluid, actuated. valve sur-
rounding said valve seat and having differential pressure areas, the reduced pressure
area of the valve being under constant motive fluid pressure, and a passage
controlled by the piston for intermittently admitting the motive fluid to the
larger pressure area of the valve, substantially as set forth.
3. In a pneumatic hammer, the combination of a piston, a piston cylinder, a
valve block closing the end of such cylinder and provided with a hollow cylin-
drical extension forming a valve seat, a valve housing, a fluid actuated valve

page_text: surrounding said valve seat, and having differential pressure areas, the reduced
pressure area of the valve being under constant motive fluid pressure, a passage
controlled by the piston and opened by the latter on its down stroke to admit
motive fluid to the larger area of the valve, and an exhaust passage leading from
said larger area of the valve and opened by the piston in its upward stroke, sub-
stantially as set forth.
4. In a pneumatic hammer, the combination of a piston, a piston cylinder, a
valve block closing the end of such cylinder and provided with a hollow cylindrical
extension forming a valve seat, a valve housing, à fluid actuated valve surrounding
said valve seat, and having differential pressure areas, the reduced pressure area
of the valve being under constant motive fluid pressure, and the larger pressure
area of the valve under an intermittent motive fluid pressure, and a longitudinal
passage connecting the lower piston chamber with the exhaust chamber of the
valve, substantially as set forth.
5. In a pneumatic hammer, the combination of a piston, a piston cylinder, a
valve block closing the end of such cylinder and provided with a hollow cylindrical
extension forming a valve seat, a valve housing, a fluid actuated valve surround-
ing said valve seat and having differential pressure areas, the reduced pressure area
of the valve being under constant motive fluid pressure, and the lower pressure
area of the valve under an intermittent motive fluid pressure, a longitudinal
passage in the cylinder and a passage through the piston, and an annular peri-
pheral chamber in the piston adapted to admit motive fluid pressure to the lower
piston chamber, substantially as set forth.
6. In a pneumatic hammer,. the combination of a piston, a piston cylinder, a
valve block closing the end of such cylinder and provided with a hollow cylin-
drical extension forming a valve seat, a valve housing, a fluid actuated valve
surrounding said valve seat, and having differential pressure areas, the reduced
pressure area of the valve being under constant motive fluid pressure, and
passages controlled by the piston, and adapted to introduce motive fluid pressure
into the enlarged valve chamber to hold the valve in its upper position, substan-
tially as set forth.
7. In a pneumatic hammer, the combination of a piston formed with a reduced
cylindrical extension on its upper end, a piston cylinder, a valve block closing
the upper end of the cylinder, and provided with a hollow cylindrical extension
forming a valve seat, and a chamber to receive the extension on the upper end of
the piston, ports connecting the upper end of such chamber with the motive fluid
supply chamber, and a valve controlling said ports, substantially as set forth.
S. In a pneumatic hammer, the combination of a piston, a piston cylinder
provided with a flanged upper end, a valve block closing the end of such cylinder,
a valve housing fitting the valve block, a handle attaching sleeve or hub fitting
over the respective parts and formed with offsets to engage the valve housing and
valve block, the lower end of such hub being internally screw threaded, and an
annular nut screwing into such lower end of the hub and abutting against the
flange of the main cylinder to clamp the various parts together, substantially as
set forth.
9. In a pneumatic hammer, the combination of a piston, a piston cylinder
provided with a flanged upper end, a valve block closing the end of such cylinder,
a valve housing fitting the valve block, a handle attaching sleeve or hub fitting
over the respective parts and formed with offsets to engage the valve housing and
valve block, the lower end of such hub being internally screw threaded and formed
with a vertical slit, lugs at the adjacent side of said slit, a clamping bolt passing
through said lugs, and an annular nut screwing into the lower end of the hub
and abutting against the flange of the main cylinder, substantially as set forth.
10. The combination in a pneumatic hammer of a reciprocating controlling valve
for the motive fluid, the shank of which is formed with an oil chamber or reservoir
and an outlet therefrom, and a needle valve controlling said outlet, and located in
the annular peripheral motive fluid passage of the valve, substantially as set forth.

page_text: 11. The combination in a pneumatic hammer of a reciprocating controlling
valve for the motive fluid, the shank of which is fermed with an oil chamber or
reservoir, the filling neck of which extends through one end of the valve, and a
stopper closing said filling neck, the said reservoir having an outlet adapted to
deliver the oil in the path of the motive fluid substantially as set forth.
Dated this 24th day of October 1899.
HERBERT HADDAN & Co.,
Agents to Applicant, 18, Buckingham Street, Strand, W.C.