Improvements in Pneumatic Hammers.
Year: 1899

page_text: Date of Application, 8th Nov., 1899-Accepted, 31st Mar, 1900
Improvements in Pneumatic Hammers.
I, HENRY JAMES KIMMAN, of 1235, Lawndale Avenue, Chicago, County of Cook
and State of Illinois, United States of America, Machinist, 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 following statement: —
-
My present invention consists in improvements on my prior Specification of
Letters Patent, No. 9239 of 1899, with particular reference to the arrangement
of parts by which the hammer is made as compact as possible and the leakages
of air due to the multiplicity of parts is reduced to a minimum.
My first improvements refer particularly to improvements in the throttle valve
& regulator for same. In my former specification employed a double headed
throttle valve with waist portion in the centre & a non-rotatable but longitudinally
movable sleeve. I further employed a bye-pass to bring the air forward of the
throttle & returned it through the inside of the longitudinally movable sleeve
around the waist portion of the throttle into the base of the hammer. It will
be noted that the opportunities for leakage were much greater in my former
invention than in the present inasmuch as a larger area at the end of the throttle
valve was exposed to the air pressure as against the correspondingly smaller
opening in my present invention, moreover the throttle valve is longer in my
present invention, and in my present invention I employ a single headed valve
as against a double headed one in said prior specification.
In order to balance my present valve I provide a small passage through tho
head of the valve to admit pressure in the rear thereof this obviates the necessity
of providing a second head at the back end of the valve and a bye-pass as in my
former invention, and at the same time assists the spring in keeping the valvo
in its normal position.
The second improvement in my present invention over my said prior specifica-
tion relates to the valve block. In my former specification I employed a valve
block received into the forward end of the handle base and held against rotary
movement by dowel pins received into recesses or openings in said handle base;
the said valve block was secured to the hammer by means of clamping the
bandle base and cylinder together by means of a coupling sleeve. It will be
observed that this method of inserting the valve block necessitated two air
tight joints at both of which there was a possibility of air escaping and further
was not so rigid as my present invention in which I insert the hammer cylinder
into the handle base. In my former invention the valve seat was bored in
a valve block transversely of its axis but in the present invention it is bored
parallel with the axis of the valve bushing and there is no valve block at
all. It will be seen in my former specification that the external diameter of the
valve block became the end wall of the cylinder whereas in my present invention
with the equivalent valve bushing or sleeve the cylinder has its own retaining
or end wall solid in the base of the handle and the said sleeve or valve bushing
is inserted in the rear and independently thereof so that practically there are
two separate walls or metals between the valve and the cylinder,

page_text: In the accompanying drawings, Figure 1 is a longitudinal sectional elevation
of a hammer, constructed in accordance with my improvements, taken on line 1
of Figure 7. looking in the direction of the arrow: Figure 2 a similar view on
the opposite half of the cylinder from that shown in Figure 1 with the hammer
portion broken away as shown in dotted outline so as to be in contact with the
operating tool Figure 3 a similar view of that shown in Figure 1 with the
operating tool, piston hammer, throttle and controlling valves removed; Figure 4
a similar view of Figure 3 showing the other half of the mechanisms; Figure 5
an enlarged view of the handle and upper part of mechanisms shown in Figure 1
with the throttle valve open and the controlling valve in position at admit
the motive fluid to the cylinder; Figure 6 a similar view to that shown in
Figure with the controlling valve in its exhaust position: Figure a plan
view of the handle portion removed from engagement with the cylinder and
looking at it from below: Figure 8 a plan view of the cylinder, looking at it
from above; Figure 9 a cross sectional view, taken on line 9 of Figure 1 looking
in the direction of the arrow; Figure 10 a sectional detail of the throttle valve,
taken on line 10 of Figure 1; Figure 11 an enlarged detail view taken on line 11
of Figure 9: Figure 12 an enlarged cross sectional view taken on line 12 of
Figure 1, looking in the direction of the arrow; Figures 13 and 14 enlarged
sectional details taken on lines 13 and 14 of Figure 1, showing the arrangement
of the fluid ducts; and Figures 15, 16 and 17 cross sectional views taken on
lines 15, 16 and 17 of Figure 1.
In the art to which this invention relates, it is well known that it is desirable
to construct a hammer with a view to having it as economical in the use of air
as possible, and at the same time providing mechanism by which the force of
the blow may be regulated to suit the desire of the operator and be maintained in
that position as long as desirable. It is further desirable to have the mechanism
of the engine arranged in such a manner that it can be taken apart and
arranged in as economical and compact a manner as possible. To accomplish
these ends are the principle object of the invention.
In constructing a portable pneumatic hammer in accordance with my improve-
ments, make the usual fluid pressure cylinder A of the desired size and
strength. The cylinder is bored out as usual, the desired diameter, so as to
provide a fluid pressure chamber a in which a piston hammer B may reciprocate.
One end (the front) of this cylinder is bored out the desired size to receive a
shouldered bushing C. as usual, which forms a portion of the front wall of the
cylinder and in which the stem of an operating tool 1 may be inserted. This
operating tool may be either a rivetting hammer, an ordinary hammer, a chisel,
a caulking tool, or the like to meet the various requirements of machines of
other manufacturers.
In the operation of this tool it is well known that the piston hammer reci-
procates within the fluid pressure cylinder a great number of times, and at one
limit of its motion strikes the operating tool that it is in effect what may be
termed a percussion tool. One of the principal objects, then is to apply the
Huid under pressure as cconomically as possible, so as to reciprocate this piston
hammer. In order to accomplish this usual result the cylinder is provided with
a number of ports and pasages some of which are arranged to be opened and
closed by the movements of the controlling valve, which I will proceed to
describe.
A controlling differential valve E is provided and arranged in the inlet and
exhaust passages so as to control and regulate the supply of air before it enters
the cylinder. This controlling valve is preferably arranged in a hardened steel
bushing in the base of the handle portion F, and transversely thereof. This
handle portion is preferably made hollow, or in other words provided with an
inlet passage divided into two parts f and fi interrupted by a throttle valve
hereinafter described.
In the operations of the tool, fluid under pressure is admitted into the

page_text: passage see Figure 1-from which it passes through the opening in the
controlling valve bushing and behind the head of the controlling valve thus
forcing it into the position shown in Figure 5. The fluid pressure is then per-
mitted to follow-see Figures 1 and 5-and pass through the larger opening e
in the valve bushing and hand portion into the cylinder back of the piston
hammer. This action forces piston hammer to its forward limit of motion, where
it strikes the operating tool, as shown in Figure 2. The piston hammer for a
portion of its length is reduced in diameter as shown at b, which in connection
with the cylinder provides an annular chamber 6' so that as the piston hammer
nears its forward limit of motion fluid pressure may pass through the passage al
into the annular chamber b' where it enters the passage a and passes upwardly
into the valve bushing between its head and the head of the controlling valve,
thus forcing the controlling valve back to the position shown in Figs. 1 and 6.
The moving of the valve into this position permits fluid under pressure to
enter the chamber of the valve through the passage e around the annular portion
from which it enters the passage and passes to the front end of the fluid
pressure chamber in the cylinder and between the piston hammer and the front
walls of the cylinder thus acting to force the piston hammer to its rearward
limit of motion. During the backward movement of the piston hammer, the
fluid at the rear part of the cylinder is forced out through the exhaust passage a
and passing through the perforations of the controlling valve, enters its central
chamber from which it passes out to the atmosphere through the passage c
During the backward movement of the piston hammer the motive fluid which
is between the head of the controlling valve and the head of the valve bushing
is permitted to pass through the passage a², through the by-pass ³, into the
annular passage from which it passes through the bye-pass a (see Figures
and 4) into the passage a², through which it is conveyed to the atmosphere. As
the superior pressure has thus been exhausted from the top end of the controlling
valve the high pressure on the lower side of the controlling valve returns it
again to the position shown in Fig. 5. This action brings the openings et of
the controlling valve into allignment with the the annular passage of the valve
chamber and permits the air to pass through such openings into the interior of
the valve and out through the passage in the handle base.
As the piston hammer continues its backward motion it passes the opening
in the exhaust passage at and confines the air in the rear portion thereof so as
to permit it to act as a cushion and at the same time imprisons a quantity of
air, which acts to prevent injurious vibration by the hammer in its rearward
movement. It will be seen that the passages a-see Figs. 2 and 13-is con-
nected with the main inlet f' for the fluid pressure so that when the throttle valve
is open this passage is in constant communication with the supply of fluid
pressure.
During the forward motion of the piston hammer, it is desirable to exhaust
the fluid pressure in front of the same. To arrange for this the passage is
in constant communication with the outer atmosphere, so that the air which
would otherwise be confined may pass out there-through. When the piston
hammer however passes this port, so as to close it, the air is exhausted out
through the passage exhaust takes place because the controlling valve is in
the position shown in Fig. 5 which position brings the perforation of the
controlling valve into allignment with the annular chamber 3, thus permitting
the air to be forced out through the passage into the annular chamber thence
through the perforations into the interior of the controlling valve, from whence
it may pass out into the passage in the handle of the hammer.
The movements of the controlling valve are positive in each direction and
longitudinal of the valve. It is desirable that these movements be made with as
small shock as possible; or in other words that a cushion of some kind be
provided whereby injury to the valve may be prevented. In order to provide this
result-see Figures 1, 5 and 6-an annular head e is arranged on the controlling

page_text: valve adjacent to its head portion and is of a diameter almost equal to the small
bore of the valve bushing. This annular head is arranged in such a manner as
to provide a small groove between it and the large head of the valve. The
front portion of the valve is provided with a boss or central offset as shown
particularly in Figs. 5 and G. As the valve is moved in one direction upwards
the air must naturally pass out through the opening a rather slowly and as a
consequence act with a cushioning effect between the head of the valve and the
head of the valve chamber. When the valve is moved towards the other side of the
chamber, as shown in Fig. 6, the annular head es first enters the small bore of
the valve chamber and as a consequence reduces the area of the free portion
of such bore, which acts to retard the passage of the air through the bore and
permits the excess of air to act as a cushion for the valve in that direction.
It is highly desirable that a throttle valve be provided of such construction
and arrangement that fluid under pressure may be shut off entirely, the maximum
amount provided, or any desired amount between the maximum and complete
shut off he supplied. This result is desirable for the reason that different
kinds of work require a different blow of the hammer for instance,--for caulking
or rivetting light and rapid blows are required while for the operation of heavy
chipping in iron or steel a heavy blow is desired, which requires the full amount
of fluid pressure. In order to accomplish this result I provide a throttle valve
bushing which is made in two parts G and G' having screw-threaded engagement
with each other one of which G is rigidly or practically immovably engaged
with the handle, as shown in Fig. 1 the other part having threaded engagement
therewith, whereby the valve bushing may be relatively shortened or lengthened
na desired. This throttle valve bushing is provided with a central chamber g
having communication with the main inlet and means of its transverse perfora-
tions with the continuation thereof. In this central longitudinal chamber
a controlling valve II is movably mounted that is arranged to reciprocate or
move backwardly and forwardly in the chamber thereof so as to open and close
the passages or ports g' and thus open or close the inlet passage which connects
the source of fluid pressure supply with the chamber of the controlling valve.
This controlling valve is provided with a stem h arranged preferably so that it
extends out through one end of the valve bushing, where it may be moved by
a pivoted lever of trigger I, which in turn is pivoted to the upper part of the
valve bushing as shown particularly in Figs. 15 and 6. This operating trigger
is so pivoted to the valve bushing that it may be moved into contact with the
handle as shown in Figs. 5 and 6, and the construction is such that at all times
this operating trigger or pivotted lever may be moved over by the thumb of
the operator, so as to contact the handle as shown in the last named figure,
thus limiting its movement in one direction. It is also provided with a small
projecting lug which limits its movement in the other direction, this movement
being due to the action of the helical spring which is inserted between the
head of the throttle valve and the head of the valve bushing as shown parti-
cularly in Figs. 1, 5 and 6. The action of this helical spring is such as to
keep the throttle valve normally closed as shown in Fig. 1. It is relieved of
the pressure of the motive fluid by a small opening being made as shown in
Figure 5 so as to connect the space in which the spring is situated with the
channel through which the motive fluid enters; the pressure thus admitted
assists the spring in keeping the valve in its normal closed position.
As the parts are arranged in Figures 1, 5 and 6 the movement of the operating
trigger so as to contact the handle as shown in Figures 5 and 6-is such as to
move the throttle valve to open the passages to their greatest extent and thereby
permit the maximum of motive fluid to enter the controlling valve chamber.
If at any time it should be desirable to use a light stroke and cut off a portion
of the supply of motive fluid, all that is necessary to do is to turn the knurled
head of the throttle valve bushing which action unscrews the bushing and
lengthens it out so as to move the ports g' towards the front of the handle. This

page_text: action it will be seen, moves the ports in such a manner that the entire swing
of the operating trigger cannot move the throttle valve sufficiently to entirely
open these porte. A further turning of the valve bushing in the same direction
will move it to such an extent longitudinally as to prevent the movements of the
throttle valve from uncovering the passages or ports g to any extent. It is
desirable that some mechanism be provided to act as a cheok and prevent the
free rotation of this valve bushing. In order to accomplish this result the
inner face of the bushing head, as shown in Fig. 10 is provided with a plurality
of indentations g' arranged to receive the pointed end of an indexing or retard-
ing ping, the operations of which are controlled by a helical spring which
acts to keep the pin in engagement with one of the recesses or depressions g¹
but will permit extraneous force to turn the valve bushing in either direction.
A handle F, as above described is provided and recessed or cupped at the
front end of the base portion to receive one end of the fluid pressure cylinder.
In order to effectually clamp the handle or head portion and the fluid pressure
cylinder together, a sleeve K is provided having an interior threaded surface
arranged to engage with an exterior threaded surface of the handle portion.
This sleeve is also provided with a shoulder adapted to abut against the
shoulder A of the fluid pressure cylinder so us to force such cylinder backwards
into contact with the inner cupped surface of the handle portion.
In order to lock the sleeve and cylinder together I provide the cylinder with
an annular toothed portion L, shown particularly in Figures 4 and 12. The
sleeve is provided with a slot b on the inside of its shoulder portion and pivotally
mounted in this slot is a click or pawl having one end provided with a pro-
jection adapted to engage the teeth on the cylinder and the other end extending
backwardly and across an opening in the sleeve. During the engagement of
the parts, and as the sleeve is turned the click or pawl rides over the annular
toothed portion and prevents the opposite movement of the parts. When it is
desired to disengage the parts a pin or other object may be pushed in through
the opening so as to engage the heel of the click and force it out of engagement
with the annular toothed portion, which permits the ring to be turned until
the tooth or projection on the click rides on the upper surface of the cylinder.
The pin or other object may then be withdrawn and the rotation of the sleeve
continued.
On reference to any of the prior specifications or an examination of the hammers
now in general use, it will be observed that the presnt form of valve block which
is composed of two or more separate parts fixed together permits of the leakage of
air and it will be readily understood that the advantage derived from having
an equivalent of the valve block in the shape of a valve bushing in one part
practically forming part and parcel of the handle base will reduce the loss of
air to a minimum.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed I wish it to be
distinctly understood that I do not claim the leading features in pneumatic
hummers, for 1 am aware that pneumatic hammers have been constructed before
all of which have cylinders, pistons, distributing, and throttle valves.-the
former being differential or otherwise ports operating in connection with the
suid valve. I am also aware that such hammers had triggers and passages through
the handles, but what 1 do claim is:-
1. In a portable pneumatic hammer having an inlet passage for the admission
of motive fluid, the combination with a throttle valve controlling such passage
of a sleeve in which the valve is mounted made in two parts, one part substantially
immovably secured to the hammer and the other part adjustably secured to the
immovable part of the sleeve so as to change the relation of the port openings
therein relative to said throttle valve, substantially as described and with reference
to the drawings annexed.

page_text: 2. In pneumatic hammers a controlling valve bushing formed of one piece and
fitted in a bore in the handle buse practically forming part and parcel of said
handle base, substantially as and for the purpose herein set forth and illustrated
in the accompanying drawings.
Dal 01
1800 ملیم
JOHN P. O'DONNELL, Fel. Chart. Inst. P.A.,
Agent for Applicant,
70/1, Palace Chambers, Westminster, S.W.