Improvements in Pneumatic and similar Hand Tools.
Year: 1895

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883) as allowed by
the decision of the Comptroller General of the 27th day of October 1898.
Date of Application, 16th Apr., 1895-Accepted, 16th Nov., 1895.
Improvements in Pneumatic and similar Hand Tools.
I, JOSEPH BOYER, of Saint Louis, Missouri, United States of America,
Engineer, 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 invention relates to that class of tools in which compressed air or other
pressure medium acts upon a reciprocating piston to cause it to deliver rapid blows
to the cutting tool movably held within one end of the casing or holder. It has
for its object the production of a tool of this character which shall be of simple,
compact and economical construction, of high officiency in operation, of the
greatest possible strength and durability proportional to the size and weight of its
constituent parts, and in which the shocks and jars occasioned by the reciproca-
tion of the piston and its action upon the tool shall be reduced to the minimum.
Its novelty consists in certain new constructions and arrangements, and combina- .
tions and modes of operation, which will be hereinafter more fully explained
and particularly pointed out in the claims. My new tool embodies as constituent
elements a casing or holder containing a chamber in which the piston is confined
and moves; a tool having its shank or stock fitted in a bore in one end of the
casing and projecting into position therein to directly or indirectly receive a blow
from the piston at one end of the stroke of the latter, and an automatic valve
mechanism controlling the admission and exhaust of pressure to and from the
cylinder or piston-chamber. In these general features my new tool resembles
that heretofore patented to me by Letters Patent of the United States No. 277,448,
dated May 15th, 1883, and in some respects my present invention consists in
improvements upon and modifications of said prior device, while in others it is a
departure therefrom and embodies entirely new constructions, arrangements, and
modes of operation. Like my prior tool my present one has a grasping handle
secured to the end of the casing at which the valve mechanism is located and
provided with means within the grasp of the operator for controlling the admis-
sion of pressure to the tool; while at the opposite end of the casing the tool stock
is fitted to reciprocate in the bore of the casing and is adapted to be held and
directed in its work by one hand of the operator while with the other he grasps
the handle of the tool and admits and cuts off the pressure as necessary.
The
means for controlling the pressure supply in my present tool differs, however,
from that of my prior one and embodies elements of novelty which constitute
certain features of my present invention, as hereinafter set forth; as likewise does
the means for securing the handle to the casing of the tool. In my prior device
the piston, which operates as a hammer or striker for actuating the tool, was
moved in both directions in its chamber or cylinder by the action of the com-

page_text: pressed air, the latter being alternately admitted to and exhausted from the
opposite ends of the cylinder. In my present tool the pressure supply is inter-
mittently admitted to and exhausted from but one end of the piston chamber, to
drive the piston forward to deliver its blow, whilst a constant pressure at the other
end of the piston-preferably the mechanical pressure of a coiled spring confined
within the front end of the piston-chamber-is employed to return the piston to
initial position. The automatic valve mechanism operates to first admit pressure
to the rear end of the cylinder, behind the piston, to drive it forward and deliver
a blow to the tool, and to then cut off the pressure supply and open the exhaust
from said end of the cylinder, to permit the spring to throw the piston.back to
initial position. In my prior tool the automatic valve was operated by a
mechanical connection with the piston. In my present one it is operated by
pressure admitted to its opposite sides. I am aware that it is common in this
art to operate the valve by such means, but heretofore in tools with which I have
been familiar the pressure has been alternately admitted to the opposite sides of
the valve and exhausted therefrom. In the valve mechanism which I employ the
pressure medium is constantly admitted at full pressure to one side of the valve,
acting upon a given area of the valve to constantly press it in one direction, and
is intermittently admitted to the opposite side of the valve and permitted to act
upon a greator area thereof, to overcome the opposing pressure and move the valve
in the opposite direction, this intermittent admission of pressure to the valve and
its exhaust therefrom being controlled by the movement of the piston in the
cylinder. In my prior tool the valve-chamber and valve are arranged parallel with
the cylinder and piston, while in my present one they are arranged transversely
across the rear end of the cylinder, between it and the grasping handle of the tool.
Having now described the general character of my new tool I will proceed to
explain and set forth.my invention in connection with a detailed description of
the mechanical embodiment of it shown in the accompanying drawings, in which
Figure 1 is a vertical longitudinal section of the complete tool; Figure 2 a
horizontal section through the handle of the same, upon the line 2-2 of Figure 1 ;
Figure 3 a sectional detail on the line 3-3 of Figure 1; Figure 4 a rear elevation
of the block containing the valve chamber and valve, and Figure 5 a front eleva-
tion of the same; Figure 6 an enlarged vertical section of the valve-chamber and
valve, showing the latter in position to admit pressure to the rear end of the
cylinder Figure 7 a corresponding view with the valve moved to position to cut
off the pressure supply from the cylinder; Figure 8 a detail vertical section on
the line 8-8 of Figure 3; Figure 9 a detail view of a portion of the coupling
sleeve showing the shape of its teeth which co-operate with the locking key;
Figure 10 a perspective view of said key; Figure 11 an enlarged sectional detail
showing the shape of the threads upon the coupling sleeve and co-operating part;
& Figure 12 enlarged perspective details of the devices for securing in place the
spring co-operating with the throttle lever.
The same letters of reference are used to indicate identical parts in all the
figures.
The casing or holder of the tool, containing the piston-chamber and piston,
consists of the cylinder 16 having an open rear end and a tapering front end, into
a bore in which latter is fitted a bushing 19 within which snugly fits and recipro-
cates the stock of the tool 18. The tool is free to be withdrawn from the holder,
and when in use will be held by the hand of the operator at the front end of the
casing 16. Fitted within the cylindrical chamber in the casing 16 is the piston 17
having in this instance a tapered front end, forming a shoulder at the base of the
tapered portion, against which shoulder rests the rear end of a coiled spring 21
fitting within the chamber and surrounding the tapered front end of the piston,
and also surrounding at its front end the portion of the bushing 19 which projects
into the chamber, and having its bearing against the front end of said chamber.
When the piston is given a full forward stroke its tapered front end will contact
with the inner end of the tool stock and give the latter a sharp blow, and when the

page_text: pressure which has driven the piston forward is released the spring 21 will throw
the piston back to its initial or rearward position. A hole 22 in the casing 16 in
front of the piston affords egress and ingress for the air in the front end of the
chamber at such movements of the piston.
In assembling the parts the bushing 19 is inserted through the piston-chamber,
from the rear end of the latter, and its reduced front end is driven tightly into
the bore 20 in the front end of the casing 16, with its shoulder abutting against
the front end of the piston-chamber. The tool stock 18 in this instanco is shown as
polygonal in cross-section, and the opening in the bushing of corresponding shape,
to prevent the tool from turning, but this is not essential and the tool-stock and
bore may be round and the tool be left free to turn. The provision of the bush-
ing 19 furnishes a longer guide-way and support for the tool-stock than could be
conveniently done if the latter were simply fitted in the bore in the front end of
the casing 16, and enables the inner end of the tool to be extended into the piston
chamber within reach of the piston while affording a support and guide for it
within said chamber.
Secured upon the rear end of the casing 16, by means hereafter described, is a
valve block 23, in this instance of the shape in cross section shown in Figure 3,
and having a cylindrical valve-chamber 34 extending vertically through it and
closed at its upper and lower ends by plugs 35 and 36, Figures 6 and 7. Fitted
within the valve chamber is a reciprocating valve 39 composed of a middle
waist portion closed at its upper end by a diaphragm and forming a cylindrical
chamber 57 in the middle of the valve, and two opposite flanged portions snugly
fitting the sides of the chamber. The rear wall of the chamber is provided with
an inlet port 37 communicating with the pressure supply, in this instance with a
duct 53 in the handle of the tool, heretofore described, and with an exhaust
port 40 opening into a duct 41 communicating with the atmosphere. The front
wall of the chamber is provided with a port 38 opening into the rear end of the
cylinder behind the piston. These ports open at their inner ends in circum-
ferential grooves in the wall of the valve-chamber, to equalize the pressure around
the valve as usual. The port 38 remains open under all conditions of the valve 39.
When the valve is in the position shown in Figure 6 the inlet port 37 is open and
the exhaust port 40 closed, so that pressure will be admitted to the cylinder
through the ports 37 and 38 and the piston be driven forward to deliver a blow
to the tool. When the valve is then moved forward to the position shown in
Figure 7, by the means hereafter described, the inlet port 37 will be closed and
the exhaust port 40 opened, so that the pressure within the cylinder will escape
through the ports 38 and 40 and permit the spring 21 to throw the piston back-
ward to the initial position.
The novel means for operating the valve 39, to first admit pressure to the
cylinder through the ports 37 and 38 and then exhaust it therefrom through the
ports 38 and 40, may be next explained. The plug 36 which closes the lower end
of the valve-chamber is provided with a central vertical extension 56 whose cylin-
drical upper end fits snugly within the waist of the valve, the latter sliding upon
this extension 56 as the valve is moved in opposite directions. The extension 56
of the plug 36 is provided with a vertical duct 58 opening at its upper end into the
chamber 57 within the waist of the valve and at its lower end into a transverse
duct in the plug communicating at its rear end with a port 51 in the rear wall of
the valve-chamber, which port 51 communicates through a horizontal and vertical
duct 52 with the pressure supply, to-wit, with the duct 53 in the handle before
referred to. This passage from the chamber 57 within the valve to the pressure
supply is always open, so that pressure is constantly admitted to the underside of
the diaphragm forming the top of the chamber 57, and tends to hold the valve in
and return it to its upper position shown in Figure 6. The pressure tending to
hold the valve in such position is intermittently overcome and the valve moved to
the position shown in Figure 7 by admitting pressure to the upper side of the valve
and permitting it to act upon a larger area of the valve than the diaphragm referred
to upon which the pressure beneath the valve acts. To this end the plug 35 which

page_text: closes the upper end of the valve chamber is provided with a duct 45 opening at
its lower end into the space above the valve 39 and communicating at its upper
end through the port 44 in the front wall of the valve-chamber with a duct 42
extending longitudinally through the wall of the casing 16 and opening at the
point 43 into the chamber containing the piston. When the piston is in initial
position, at the rear end of the cylinder, it closes the end 43 of the duct 42, so
that no pressure is admitted to the upper side of the valve, but when the piston
is thrown forward by the admission of pressure to the rear end of the cylinder
the end of the duct at 43 will be uncovered as the piston reaches the forward end
of its stroke, and the pressure within the cylinder will be admitted through the
duct 42, port 44 and duct 45 to the upper side of the valve, and there acting not
only upon the upper side of the diaphragm in the waist of the valve but also
upon the annular portion of the valve surrounding the diaphragm it overcomes
the pressure beneath the valve and forces the latter downward to the position
shown in Figure 7, thereby closing the inlet port 37 and opening the exhaust
port 40 and permitting the pressure to escape from the cylinder and the spring 21
to throw the piston back to initial position.
For the purpose of preventing the pressure from escaping from the upper side of
the valve, when the exhaust port 40 is opened and the pressure permitted to
escape from the cylinder, there is provided a check-valve at some point in the
passage between the upper side of the valve 39 and the cylinder; in the present
instance the check-valve is located at the lower end of the duct 45 in the plug 35.
The valve shown in the drawings consists of a thin circular plate or disc 46
fitting loosely over a depending central stem 47 of the plug 35 and yieldingly
held in place, to close the lower end of the duct 45, by a spring or springs 48
secured to the stem 47 beneath the disc. When the passage 42 communicating
with the cylinder is opened by the piston at the end of its forward stroke and
the pressure from the cylinder admitted through said passage and the duct 45
the disk 46 will readily yield thereto and permit the pressure to pass into the
space beneath it and act upon the upper side of the valve 39. When the pressure
is exhausted from the cylinder by the opening of the exhaust port 40 the pressure
within the valve chamber, beneath the check-valve, will force the disc 46 tightly
against its seat and close the lower end of the duct 45 and prevent escape of such
pressure. For the purpose of releasing this pressure when the piston has been
returned to initial position, and thereby permitting the constant pressure upon
the under side of the valve to lift it and again admit pressure to the cylinder to
throw the piston forward, the wall of the casing 16 is provided with a second
longitudinal duct 49 opening at its front end into the cylinder at a point in
front of the piston when the latter is in initial position, and communicating at
its rear end through a port 50 with the space at the upper side of the valve 39
beneath the check-valve. As the spring throws the piston forward to initial
position the front end of the duct 49 will be uncovered and the pressure at the
upper side of the valve will escape through the port 50 and the duct 49 into the
cylinder, whereupon the pressure at the under side of the valve will imme-
diately lift the valve and close the port 40 and opon the port 37, causing the
piston to be thrown forward to deliver another blow and the operation above
described to be. repeated.
I am aware that reciprocating valves have been operated by constant pressure
at one side of them and intermittent pressure at the opposite side, and that the
admission and exhaust of such intermittent pressure have been controlled by the
piston, but so far as I am aware I am the first in the art to employ a check-valve
of any sort arranged in any manner in the passage controlled by the piston for
intermittently admitting pressure to the valve, and my invention in this respect
is of corresponding scope.
A duct 59 connects the space at the inner side of the valve, around the central
vertical extension 56 of the plug 36, with the exhaust duct 41. This duct 59 is
always open and furnishes a means of ingress and egress for the air as the
valve 39 moves up and down upon the central extension of the plug 36.

page_text: The inner ends of the plugs or blocks 35 36, which form the opposite ends of the
valve chamber, are cut away or made of reduced diameter to form annular seats for
the flanged ends of the valve, the exhaust ports 50 and 59 opening into these seats.
As the valve approaches the end of its stroke in either direction its flanged end
cuts off the escape of air in front of it as soon as such flanged end enters the
annular seat above referred to, so that there is a body of air then confined in front
of the valve to cushion it and relieve it of any shock or jar.
From the foregoing description the following operation of the valve mechanism
and piston will be understood, starting with the parts in the position shown in
Figures 1 and 6. .When the throttle valve, hereafter described, controlling the
pressure supply in the duct 53, is opened the pressure passes through the ports 37
and 38 into the rear end of the cylinder and drives the piston forward and causes
it to deliver a blow to the tool, the coiled spring 21 being compressed by such
forward movement of the piston and the air in front of the piston escaping through
the opening 22. As the piston reaches the forward limit of its stroke its rear end
passes in front of the open end.43 of the duct 42 and uncovers the same, whereupon
pressure, passes from the cylinder through said duct and the passages 44 and 45
and check-valve 46 into the space above the valve 39 and forces the latter down-
ward against the pressure upon its under side, to the position shown in Figure 7,
thereby, closing the port 37 and opening the exhaust port 40, whereupon the
pressure, within the cylinder escapes through the ports 38 and 40 and permits the
spring to reset the piston. As the latter reaches initial position it uncovers the end
of the duct 49 and permits the escape of the pressure in the space above the valve
through the exhaust port 50 and passage 49, whereupon the constant pressure upon
¡the under side of the valve lifts the latter again to the position shown in Figure 6
and again admits. pressure to the cylinder. In this manner the: pressure supply,
automatically controlled by the valve mechanism, in co-operation with the spring
21 will cause an exceedingly rapid reciprocation of the piston 17 and consequent
, actuation of the tool 18.
It will be noticed that when the piston is moved forward to its limit of stroke
its rear end will have passed some little distance to the front of the open end 43
of the duct 42, and likewise that when the piston is in its rearward or initial
position the front end of its full cylindrical portion is some little distance in rear
of the open end of the duct 49. The result of this arrangement is that in its
forward movement, to deliver a blow to the tool, the rear end of the piston will
qlear and uncover the end 43 of the duct 42 before the piston reaches its limit of
movement and contacts with the tool, and as the opening of the duct 42 imme-
diately shifts the valve 39 and opens the exhaust from the cylinder it will be seen
that the actual impact of the piston with the tool is caused by the momentum
of the piston, rather than by the direct action of pressure, and that at the moment
of contact the piston is cushioned against the compressed spring 21, the result
being that the blow given the tool is an exceedingly sharp, quick and elastic one,
instead of a dead blow such as would be produced by the direct action of pressure.
The return movement of the piston is begun with the elastic rebound and the
tool is relieved of the severe shock and jar incident to many of this class.
Furthermore, it will be seen that in the return movement of the piston the duct 49
will be uncovered before the piston reaches initial position, and inasmuch as the
valve is shifted to admit pressure to the rear end of the cylinder the instant the
duct 49 is uncovered it will be seen that as the piston reaches initial position it
is cushioned against the newly admitted pressure and rebounds therefrom to its
next forward stroke. In this manner the shock at each end of the stroke of the
piston is reduced to the minimum, with a consequent saving of wear and tear
upon the tool and injury to the nerves of the operator.
In tools of this class, if the end of the piston is solid and fits snugly against the
end of the piston-chamber the shock occasioned by suddenly admitting the
operating medium at full pressure is much the same as if a powerful blow were
given to the piston with some implement. To relieve such shock in my tool I

page_text: provide the rear end of the piston with a concave recess as indicated by the dotted
lines in Figure 1. The provision of this cavity permits the initial supply of air
admitted to the piston-chamber to slightly expand and to start the piston forward
with an expansive elastic pressure instead of with the dead blow of suddenly
admitted full pressure. So, too, the provision of the cavity aids to some extent
the cushioning of the piston at the end of its backward stroke, causing it to be
arrested by the compressible yielding pressure and to be started forward again
by the elastic rebound from the same. It will be understood, however, that, the
purpose of this provision being merely to relieve the tool from shock, it may be
dispensed with without otherwise affecting the operation of the tool.
My novel valve mechanism will operate in the manner described to admit
pressure to and exhaust it from the piston chamber behind the piston, no matter
by what means the constant pressure at the front end of the chamber, for
resetting the piston, is produced.
As before stated, I prefer to employ a coiled spring confined in the front end of
the piston-chamber, for that purpose, and the particular construction and arrange-
ment of the parts illustrated in the drawings and heretofore described are highly
advantageous and have proved exceedingly satisfactory, as regards easy and
economical construction, efficiency in operation, durability and strength, and
general adaptability to the requirements of the art; yet such particular construc-
tion and arrangements of the parts may be considerably varied without departing
from my invention, and so far as the employment of the coiled spring in the front
end of the piston chamber is concerned, the resetting spring may be otherwise
applied to the piston; or, without departing from the broader scope of my inven-
tion other means for producing a constant resetting pressure upon the front end
of the piston may be substituted for the spring. Thus, the piston and its chamber
may be so shaped that a constantly admitted supply of the compressed air or
other operating medium, acting upon a small area of the front end of the piston,
will serve the purpose of the spring in resetting the piston after it has delivered
its blow to the tool. Such a substitution of the pressure medium for the spring,
as a resetting means for the piston, may be understood without illustration or
description here by reference to my aforesaid prior patent, where it will be seen
that the pressure admitted to and exhausted from the front end of the cylinder
acts only upon an annular shoulder upon the piston, thus serving to reset it
with much less force that it is driven forward. By admitting a constant supply
of the pressure to the front end of the cylinder, instead of intermittently admitting
and exhausting it, the piston would be constantly pressed rearward and reset
whenever the exhaust from the rear end of the cylinder permitted, as will be
readily understood.
I am aware that it has heretofore been proposed to move the piston of a
pneumatic tool in one direction by pneumatic pressure and in the opposite
direction by a coiled spring, and I do not broadly claim the use of a spring in
my tool for such purpose, as will be seen from the terms of the respective claims
directed to this feature of my invention.
The parts so far described, (assuming the part 26 containing the pressure
supply duct 53, the exhaust duct 41, and the ducts 51, 52, and 59, to be simply a
head-block or cap piece secured against the rear face of the valve block 23.)
would constitute an operative and useful tool and embody all the novel features
of my invention which relato to the automatic valve mechanism and tool proper.
Further features of my invention, however, relate to the handle, of which the
block 26 above referred to forms an integral part; to novel means for coupling
said handle to the tool proper; and to a novel hand-operated valve mechanism
or throttle for admitting and cutting off the pressure supply at will. These
features of my invention may now be described. The handle proper consists
preferably of a portion 60 of approximately the shape shown in Figures 1 and 2
of the drawings, which is adapted to be grasped in one hand of the operator in
the manner of the ordinary hand-saw or other like tool, and a reduced reversely
curved neck portion connecting the part 60 with the circular block 26. This
block is provided in its forward side with a rectangular recess in which fits the

page_text: middle rearwardly projecting portion of the valve block 23, as seen in Figure 3,
the block 26 thus embracing and snugly fitting said projecting portion of the
valve block. The rear end of the casing 16 is provided with a peripheral flange 25
over which fits the front end of a coupling sleeve 24 having an internal annular
flange engaging the flange 25. The portion of the sleeve in rear of the casing
and flange 25 is internally threaded and screwed upon the threaded circular
periphery of the block 26. By means of this connection said block and the
handle are securely attached to the tool proper and the valve block held in posi-
tion between the handle and casing, within the coupling sleeve. To facilitate
the assembling of the parts in true position they may be provided with co-operat-
ing dowel pins and holes 54 and 55, Figures 4 and 5.
The connection of the handle to the tool by the means above described would
be reasonably secure for ordinary purposes, but inasmuch as tools of this character
are subjected to continuous jarring from the reciprocation of the piston and its
action upon the tool, means of connection which in other implements would be
amply secure are not always sufficient to prevent the parts becoming loosened
from each other. In my present tool I have provided novel means for meeting
this difficulty, which means not only prevents the connection of the parts becom-
ing loosened by the jarring of the tool but tends to cause such jarring to more
tightly bind them together. Such means consists of a spring-pressed locking
key fitted in a longitudinal recess or guide-way and having oblique or cam lock-
ing surfaces adapted to engage teeth or notches upon the coupling sleeve and
tending to force the latter more tightly upon the part upon which it is screwed.
An enlarged perspective view of the locking key is shown in Figure 10. It fits
in a recess or guide-way in one side of the tool, Figure 3, the cylindrical rear
portion 28 of the guide-way being formed in the block 26 and the reduced
rectangular forward portion 31 of the same being formed in the casing 16, an
opening at 34a through the valve block 23, Figures 4 and 5, forming the middle
connecting portion of the recess or guide-way. As seen in Figure 3 the
rectangular front end 31 of the guide-way passes beneath the peripheral flange 25
of the casing 16 and its upperside is flush with the surface of said casing. The
enlarged rear end of the key 27 is cylindrical in shape, while its reduced front
end is of rectangular shape in cross section to snugly fit the front end of the
recess or guide-way and prevent the key from turning. Upon the outer side of
the rectangular forward half of the key are formed one or more locking ribs or
cam surfaces 32, obliquely disposed upon the key and inclined downward from
the cylindrical portion of the key toward its front end. These locking ribs are
adapted to engage teeth or notches 33 formed upon the inner edge of the internal
flange of the coupling sleeve 24, Figures 8 and 9, such notches or teeth having
substantially the same inclination to the line of movement of the key as have
the locking ribs 32 of the latter, as seen in Figure 9. In assembling the parts
the key is held in the rear end of its recess, with the locking ribs in rear of the
toothed flange of the sleeve, until the latter is screwed as tightly as possible upon
the block 26, in the direction of the arrow in Figure 8. When the key is pressed
forward its locking ribs 32 engage with the notches 33 in the flange of the
coupling sleeve, as seen in Figure 8, and a coiled spring 29 confined in the
recess behind the key and bearing upon the same tends to drive it further for-
ward. It will be seen from Figures 8 and 10 that any forward movement of the
key will tend to turn the sleeve 24 in the direction of the arrow and screw it more
tightly upon the block 26, and in the operation of the tool when any loosening
of the parts is occasioned by the jarring the spring 29 forces the key forward,
causing it to take up any play of the sleeve 24 and lock it tightly upon the
block 26. In this manner the spring-pressed key at all times tends to force the
sleeve more tightly upon the block and immediately takes up any looseness occa-
sioned by the jarring and thereby constantly maintains a firm connection of
the handle with the valve block and casing.
For the purpose of additional security in the connection of the handle and valve
block with the casing of the tool the threads of the parts 24 and 26, instead of
having both faces inclined, in the usual manner, are made of the form shown in

page_text: Figure 11, where it will be seen that the retaining surfaces of the threads are
"transverse to the axis of the parts, thus presenting bearing surfaces at right angles
to the line of stress and preventing the tendency to a spreading or enlargement
of the nut and consequent loosening of the parts, which would otherwise be
'occasioned by the jarring and stresses to which the tool is subjected.
The novel valve mechanism contained' within the grasping portion 60 of the
handle may be next described. The duct 53, which communicates with the source
of pressure supply, as heretofore referred to, extends upward from the block 26
through the curved neck of the handle and thence downward through the grasping
'portion 60 and opens through the lower end of the same. Its lower portion within
the handle is enlarged to form a cylindrical chamber 61 into whose lower end is
screwed the nipple 62 upon the end of the usual flexible tube leading to the
pressure supply. The internally threaded lower end of the chamber 61 is prefer-
ably slightly larger'in diameter than the body of the chamber, forming an annular
shoulder 66 at the lower end of the latter. Snugly fitting within the chamber 61,
is a section of rubber or other flexible tubing 63 preferably provided around its
lower end with a flange which fits against the shoulder at 66. A tubular locking
plug 64 is screwed into the threaded lower end of the chamber, above the nipple 62,
and abuts against the shoulder 66 and 'confines the flange of the tube 63 against
'said shoulder, while its vertical 'projecting tubular section extends upward a short.
distance within the tubing 63. The tubing may, however, be secured within its
chamber in any other suitable or convenient manner which will compel the
'pressure supply to pass through the tube and prevent it passing around it.
"
It will be seen from this construction that the pressure supply may be admitted
to the tool or cut off at will by collapsing the tube 63, Figure 1, and the means
which have been illustrated for effecting this may be next described. Mounted in
a cylindrical guide-way 74 opening at its front end into the valve chamber, 61' is a
sliding plunger 73 having a rounded front end adapted to bear against the rear
side of the flexible tube 63. By pressing this plunger forward to the position
shown in Figures 1 and 2 the rear wall of the flexible tube will be pressed tightly
"against its front wall and the passage through the valve be closed to cut off the
pressure supply. As a convenient means for operating the plunger 73 there is
provided a lever 72 fitting within a narrow recess 68 within the rear half of the
handle 60 and hung by its hook 69 upon a fixed pivot pin 70. The body of this
lever is enclosed within the recess 68, but its upper end projects therefrom and is
'provided with a thumb-piece 71, in position for the thumb of the operator to rest
upon it. The lower end of the lever extends through an opening 75 in the sliding
plunger 73: A coiled expansive spring 76 confined in a diagonal bore 82 in the
handle and bearing against the lever 'above its fulcrum presses the lower end of
the lever forward and yieldingly holds it and the plunger 73 in the position shown
in Figures 1 and 2, with the valve closed. When the operator' desires to set the
tool in motion he has simply to press upon the thumb-piece 71 at the upper end
of the lever and rock it slightly upon its fulcrum to permit the plunger 73 to move
rearward and the valve to open.
M
i
This valve is efficient in opération, cheap in construction, and when worn may
be easily and quickly replaced with a 'new one.
T
"
Other means than the lever 72 may be employed for operating the sliding
plunger 73, and when a lever such as 72 is used the spring may be applied to such
lever in any suitable manner. "The particular arrangement of the spring 76
and its mode of application to the lever in the present instance, however, constitute
a' novel feature of my invention, which may now be explained more in detail by
reference to 'Figures' 1 and 12. The lower end of the spring is fastened to a nipple
77 whose lower end is slotted to form arms 78 which fit over and embrace the edge
of the lever 72. Secured to the upper end of the spring is a nipple 79 provided in
its upper end with a transverse nick '80 adapted to co-operate with a rib 83 upon
the lower end of 'a screw plug 81 which is screwed into the internally threaded
upper end of the bore 82 and is provided in its upper end with a nick for the recep-
Be th
:
17.11. . .I.
TH

page_text: tion of an instrument for turning it. The spring 76 and nipple 79 are held from
turning by the engagement of the arms 78 of the lower nipple with the lever. 72,
and to permit the screw plug 81 to be turned to regulate the tension of the spring
either the nick in the upper end of the nipple 79 has inclined walls or the rib 83
upon the lower end of the plug 81 has beveled sides, so that the engagement
of the one with the other will prevent the plug from turning and becoming
loosened under the jarring of the tool, yet the plug may be positively turned by
an instrument engaged with the nick in its upper end, to regulate the tension of
the spring.
The spring 29 which bears against the rear end of the key 27 may be held
in place by a nipple and screw plug similar to the nipple 79 and plug 81 above
described.
It is a desideratum in this art to produce a tool of the smallest size and most
compact construction, and of the least weight, consistent with the requisite strength
and durability, and power and efficiency in operation; and particularly is it
desirable to decrease the length of the tool to the minimum. At the same time it
is important that the piston shall have a considerable length of stroke, in order
that the pressure may have time to properly act upon it, in order that it may be
properly cushioned at each end of its stroke, and in order that it may strike the
tool with a sharp elastic momentum blow and rebound without shock. In many
tools heretofore devised decreased length of the tool has been attained at sacrifico
of the length of the stroke of the piston, so that the latter cannot be properly
cushioned, has to be started at each end of its stroke by the sudden dead action
of the full pressure, and strikes the tool a solid, dead and unyielding blow, with
a consequent jarring of the whole tool and discomfort and injury to the operator.
In my tool the novel construction and arrangement of the parts which have been
shown and described enable me to give the piston full length of stroke, with all
its attendant advantages, without increasing the length of the tool as a whole.
The comparatively short piston, and the arrangement of the spring with one
end surrounding the front end of the piston and the other surrounding the inner
end of the bushing and tool stock, afford room for the long spring and accommo-
date the long stroke of the piston without unduly increasing the length of the
casing containing the piston chamber; while the arrangement of the valve
chamber transversely across the rear end of the piston.chamber and its attach-
ment thereto by the head block fitting over and embracing the valve block, and
the coupling sleeve surrounding the valve block and screwed upon the head block
and binding the parts together, cause the valve mechanism to add but very
little to the length of the piston chamber, so that the whole of the tool proper
is but little longer than the casing containing said chamber.
It will also be seen that the construction employed is adapted to a firm
attachment of the several parts together and a maximum resistance to the shocks
and stresses to which the tool is subjected. Thus, the casing or holder 16 being
cast in a single piece is much better adapted to the latter purpose than is a
casing composed of two or more parts screwed together as is common.. So, the
bushing 19 driven from the interior of the piston chamber through the bore 20
in the end of the casing, with its shoulder. abutting against the end of the
chamber, and with the action of the piston tending to maintain it in..position
instead of displacing it therefrom is much more firmly secured to the casing
than if it were screwed from the exterior into a threaded bore in the end of the
casing in the usual manner. And the coupling sleeve 24 surrounding the valve
block 23 and screwed upon the head block 26 of the handle, with the locking
key constantly tending to force it more tightly thereon, binds the handle to the
casing, and piston-chamber, and clamps the valve block and valve mechanism
between the same, with the greatest possible security.
Again, the construction and arrangement of the parts shown are conducive to
the ready assemblage of the parts and the ready removal and replacement of any
one of them. Thus, if the spring 21 becomes weakened or broken, by simply

page_text: unscrewing the coupling sleeve 24 the casing 16 may be detached from the valve
block and handle, the piston removed, the old spring replaced with a new one,
and the parts be quickly assembled and secured together again. So, if the flexible
throttle valve becomes worn the tube may be readily removed from the valve
chamber by unscrewing the nipple 62 and plug 64, and a new tube be put in
its place. The, fulcrum pin 70 of the lever 72 may be riveted in the handle so
that it cannot become loosened, and the lever be put in place afterwards, and be
removed and replaced at will by removing the spring 76.
While the foregoing and other advantages are derived from the particular
construction and arrangement of the parts, yet other features of my invention
are quite independent thereof and in no wise restricted thereto, and I do not
wish to be understood, by describing such construction and arrangement in
detail and setting forth their advantages, as intending to limit my invention
beyond the terms of my respective claims or the requirements of the prior art.
Having now particularly described and ascertained the nature of the 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 casing or holder containing a
piston-chamber and adapted to hold a reciprocating tool at its front end, a
piston in said chamber adapted to deliver a blow to the tool at the end of its
forward stroke, a spring within the chamber for resetting the piston and against
the resistance of which the piston is moved by the pressure medium to deliver
its blow, and an automatic valve mechanism in fixed position at the rear end
of the piston-chamber and operated by constant pressure at one side of the
valve and intermittent pressure admitted to the other, for controlling the admis-
sion of pressure to and its exhaust from the piston chamber behind the piston,
substantially as described.
2. In a pneumatic tool, the combination of a casing or holder containing a
piston-chamber, a reciprocating tool fitting in the front end of the casing and
projecting into the piston-chamber, a piston in said chamber having a reduced
forward end adapted to deliver a blow to the tool at the end of the forward
stroke of the piston, a coiled resetting spring confined in the front end of the
chamber and surrounding the inner end of the tool stock at one end and the
reduced front end of the piston at the other, and an automatic valve mechanism
in fixed position at the rear end of the piston-chamber for controlling the admis-
sion of pressure to and its exhaust from the piston-chamber behind the piston,
substantially as described.
3. In a pneumatic tool, the combination of a casing or holder containing a
piston-chamber opening at its full diameter through the rear end of the casing
and through a bore of reduced diameter at the front end of the casing, a
shouldered bushing being inserted in the casing through its open rear end and
fitted tightly in the bore in its front end, a reciprocating tool fitting in said
bushing, a piston within the chamber, a coiled spring confined in the front end
of the chamber with its front end surrounding the inner end of the bushing
and tool and at its rear end bearing against the piston, and an automatic valve
mechanism at the rear end of the casing controlling the admission of pressure
to and its exhaust from the rear end of the piston-chamber behind the piston,
substantially as described.
4. In a pneumatic tool, the combination of a casing or holder containing a
piston-chamber and adapted to hold a reciprocating tool at its front end, a piston
in said chamber adapted to deliver a blow to the tool at the end of its forward
stroke, resetting means for the piston exerting a constant pressure upon the piston
and against the resistance of which the piston is driven forward to deliver its blow
to the tool, and an automatic valve mechanism in fixed position at the rear end of
the piston-chamber operated by the pressure medium to admit pressure to and
exhaust it from the rear end of the piston chamber only, substantially as described.
5. In a pneumatic tool, the combination of a casing or holder containing a
piston-chamber and adapted to hold a reciprocating tool at its front end, a piston

page_text: in said chamber adapted to deliver a blow to the tool at the end of its forward
stroke, resetting means for the piston exerting a constant pressure upon the piston
and against the resistance of which the piston is driven forward to deliver
its blow to the tool, and an automatic valve confined in a fixed chamber at the
rear end of the casing and operated by constant pressure at one side of it and
intermittent pressure admitted to the other for controlling the admission of
pressure to the piston chamber behind the piston, substantially as described.
6. In a pneumatic tool, the combination of a casing or holder containing a
piston chamber and adapted to hold a reciprocating tool at its front end, a piston
in said chamber adapted to deliver a blow to the tool at the end of its forward
stroke, resetting means for the piston exerting a constant pressure upon the front
end of the piston and against the resistance of which the piston is driven forward
to deliver its blow to the tool, a reciprocating valve for controlling the admission
of pressure to the piston-chamber behind the piston, a passage for constantly
admitting pressure to one side of said valve, and a second passage controlled by
the piston for intermittently admitting pressure to the opposite side of said
valve, substantially as described.
7. In a pneumatic tool, the combination of a casing or holder containing a
piston chamber and adapted to hold a reciprocating tool at its front end, a piston
in said chamber adapted to deliver a blow to the tool at the end of its forward
stroke, resetting means for the piston exerting a constant pressure upon the
front end of the piston and against the resistance of which the piston is driven
forward to deliver its blow to the tool, a reciprocating valve for controlling
the admission of pressure to the piston-chamber behind the piston, a passage for
constantly admitting pressure to one side of said valve, a second passage con-
trolled by the piston for intermittently admitting pressure to the opposite side
of said valve, a check valve in said last mentioned passage, and an exhaust
passage controlled by the piston and communicating with the valve-chamber
between the check-valve and main valve, substantially as described.
8. In a pneumatic tool, the combination of a casing or holder containing a
piston-chamber and adapted to hold a reciprocating tool at its front end, a piston
in said chamber, adapted to deliver a blow to the tool at the end of its forward
stroke, a spring within the chamber for resetting the piston, and an automatic
valve operated by constant pressure at one side of it and intermittent pressure
admitted to the other, for controlling the admission of pressure to and its exhaust
from the piston-chamber behind the piston, substantially as described.
9. In a pneumatic tool, the combination of a piston-chamber, a piston
therein, a resetting spring for the piston, a reciprocating valve for controlling
the admission of pressure to and its exhaust from the piston-chamber, a passage
for constantly admitting pressure to one side of said valve, a second passage
controlled by the piston for intermittently admitting pressure to the opposite
side of said valve, and a check valve in said last mentioned passage, substantially
as described.
10. In a pneumatic tool, the combination of a piston-chamber, a piston therein,
a resetting spring for the piston, a reciprocating valve for controlling the admis-
sion of pressure to and its exhaust from the piston-chamber, a passage for con-
stantly admitting pressure to one side of the valve, a second passage controlled
by the piston for intermittently admitting pressure to the opposite side of said
valve, and a separate exhaust passage communicating with said last mentioned
side of the valve and controlled by the piston, substantially as described.
11. In a pneumatic tool, the combination of a piston-chamber, a piston therein,
a resetting spring for the piston, a reciprocating valve for controlling the admis-
sion of pressure to and its exhaust from the piston-chamber, a passage for con-
stantly admitting pressure to one side of said valve, a second passage controlled
by the piston for intermittently admitting pressure to the opposite side of the
valve, a check valve in said last mentioned passage, and an exhaust passage con-

page_text: -
trolled by the piston and communicating with the valve-chamber between the
check valve and main valve, substantially as described.
12. In a pneumatic tool, the combination of a piston-chamber, a piston therein,
resetting means for the piston exerting a constant pressure upon the front end of
the piston and against the resistance of which the piston is driven forward to
deliver its blow to the tool, a valve-chamber at the rear end of the piston-
chamber, having an inlet and an exhaust port, and a constantly open port com-
municating with the piston-chamber behind the piston, and a valve in said
chamber operating to intermittently admit pressure to and exhaust it from the
valve chamber, substantially as described.
13. In a pneumatic tool, the combination of a piston-chamber, a piston
therein, resetting means for the piston exerting a constant pressure upon the
front end of the piston and against the resistance of which the piston is driven
forward to deliver its blow to the tool, a valve-chamber at the rear end, of
the piston-chamber, having an inlet and an exhaust port, and a constantly
open port communicating with the piston-chamber behind the piston, a recipro-
cating valve in the valve-chamber, a passage for constantly admitting pressure to
one side of the valve, and a second passage controlled by the piston for inter-
mittently admitting pressure to its opposite side, substantially as described.
14. In a pneumatic tool, the combination of a piston-chamber, a piston
therein, resetting means for the piston exerting a constant pressure upon the
front end of the piston and against the resistance of which the piston is driven
forward to deliver its blow to the tool, a valve-chamber at the rear end of the
piston-chamber, having an inlet and an exhaust port, and a constantly open
port communicating with the piston-chamber behind the piston, a reciprocating
valve in said valve-chamber, a passage for constantly admitting pressure to one
side of the valve, a second passage controlled by the piston for intermittently
admitting pressure to the opposite side of the valve, a check valve in said last
mentioned passage, and an exhaust passage communicating with the valve-
chamber between the check valve and main valve and controlled by the piston,
substantially as described.
15. In a pneumatic tool, the combination of a piston-chamber, a piston
therein, a resetting spring for the piston, a valve-chamber having an inlet and
an exhaust port and communicating with the rear end of the piston chamber by
a constantly open port or passage, and a valve in said valve-chamber, operating
to intermittently admit pressure to and exhaust it from said chamber, sub-
stantially as described.
16. In a pneumatic tool, the combination of a piston-chamber, a piston therein,
a resetting spring for the piston, a valve-chamber having an inlet and an exhaust
port and communicating with the rear end of the piston-chamber by a constantly
open. port, a reciprocating valve in the valve-chamber, a passage for constantly
admitting pressure to one side of the valve, and a second passage controlled by
the piston for intermittently admitting pressure to its opposite side, substantially
as described.
[!
17. In a pneumatic tool, the combination of a piston-chamber, a piston
therein, a. resetting spring for the piston, a valve-chamber having an inlet and
, and exhaust port and communicating with the rear end of the piston-chamber by
a constantly open port, a reciprocating valve in the valve-chamber, a passage
for constantly admitting pressure to one side of the valve, for moving it to and
yieldingly, holding it in position to admit pressure to the chamber, and a
second passage controlled by the piston for intermittently admitting pressure
to the opposite side of the valve to overcome said constant pressure and move
the valve to position to close, the inlet port and open the exhaust port, sub-
stantially as described.
t
18. In a pneumatic tool, the combination of a piston-chamber, a piston therein,
a resetting spring for the piston, a valve-chamber at the rear end of the piston-
chamber, having an inlet and an exhaust port and a constantly open port
communicating with the piston-chamber behind the piston, a reciprocating valve
in said chamber, a passage for constantly admitting pressure to one side of the
valve, a second passage controlled by the piston for intermittently admitting

page_text: pressure to the opposite side of the valve, a check-valve in said last mentioned
passage, and an exhaust passage communicating with the valve-chamber between
the check valve and main valve and controlled by the piston, substantially as
described.
19. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination, with a reciprocating valve, of a suitably controlled passage
for intermittently admitting pressure to one side of said valve, a check valve
in said passage, and an exhaust passage communicating with the valve-chamber
between the check valve and main valve, substantially as described.
20. In an automatic valve mechanism, for pneumatic and similar hand tools
the combination, with a reciprocating valve, means operating against one side
of said valve to constantly press it in one direction, a suitably controlled passage
for intermittently admitting pressure to the opposite side of said valve, and a
check valve in said last mentioned passage, substantially as described.
21. In an automatic valve mechanism, for pneumatic and similar hand tools
the combination, with a reciprocating valve, of a passage for constantly admit-
ting pressure to one side of the valve, a passage suitably controlled for inter-
mittently admitting pressure to the opposite side of said valve, and a check valve
in said last mentioned passage, substantially as described.
22. In an automatic valve mechanism, for pneumatic and similar hand tools
for controlling the admission of pressure to and its exhaust from the piston-
chamber, the combination, with a reciprocating valve, of a passage for con-
stantly admitting pressure to one side of the valve, a second passage controlled
by the piston for intermittently admitting pressure to the opposite side of said
valve, and a check valve in said last mentioned passage, substantially as described.
23. In an automatic valve mechanism, for pneumatic and similar hand tools
for controlling the admission of pressure to and its exhaust from the piston-
chamber, the combination, with a reciprocating valve, of a passage for constantly
admitting pressure to one side of the valve, a second passage controlled by the
piston for intermittently admitting pressure to the opposite side of said valve, a
check valve in said last mentioned passage, and an exhaust passage controlled
by the piston and communicating with the valve-chamber between the check
valve and main valve, substantially as described.
24. In a pneumatic tool, the combination of a piston-chamber open at its rear
end, a piston therein, resetting means for the piston exerting a constant pressure
against its front end and against the resistance of which the piston is driven
forward to deliver its blow, a separate valve-block secured to the rear end of
the piston-chamber to close the same, and containing a valve-chamber having
an inlet and an exhaust port, and a constantly open port communicating with
the piston-chamber behind the piston, and a reciprocating valve in said valve-
chamber for intermittently admitting pressure to and exhausting it from the
valve-chamber, substantially as described.
25. In a pneumatic tool, the combination of a piston-chamber open at its
rear end, a piston therein, resetting means for the piston exerting a constant
pressure against its front end and against the resistance of which the piston is
driven forward to deliver its blow, a separate valve-block secured to the rear
end of the piston-chamber, to close the same, and containing a valve-chamber
having an inlet and an exhaust port, and a constantly open port communicating
with the piston-chamber behind the piston, a reciprocating valve in said cham-
ber, an inlet passage from the pressure supply for constantly admitting pres-
sure to one side of said valve, and a second passage controlled by the piston for
intermittently admitting pressure to the opposite side of the valve, substantially
as described.
26. In a pneumatic tool, the combination of a piston-chamber at its rear end,
a piston therein, resetting means for the piston exerting a constant pressure
against its front end and against the resistance of which the piston is driven
forward to deliver its blow, a separate valve block secured to the rear end of
the piston-chamber, to close the same, and containing a valve-chamber having
an inlet and an exhaust port, and a constantly open port communicating with

page_text: the piston-chamber behind the piston, a reciprocating valve in said chamber, an
inlet passage from the pressure supply for constantly admitting pressure to one
side of said valve, a second passage controlled by the piston for intermittently
admitting pressure to the opposite side of said valve, a check valve in said last
mentioned passage, and an exhaust passage controlled by the piston and com-
municating with the valve chamber between the check valve and main valve,
substantially as described.
27. In a pneumatic tool, the combination of a piston-chamber open at its
rear end, a piston therein, a resetting spring for the piston, a separate valve-
block secured to the rear end of the piston-chamber for closing the same, and
containing a valve-chamber transverse to the piston-chamber, said valve-cham-
ber having an inlet and an exhaust port and a constantly open port communi-
cating with the piston-chamber behind the piston, and a reciprocating valve in
said valve-chamber for intermittently admitting pressure to and exhausting it
from the valve-chamber, substantially as described.
28. In a pneumatic tool, the combination of a piston-chamber open at its rear
end, a piston therein, a resetting spring for the piston, a separate valve block
secured to the rear end of the piston-chamber, for closing the same, and con-
taining a valve-chamber having an inlet and an exhaust port and a constantly
open port communicating with the piston-chamber behind the piston, a recipro-
cating valve in said chamber, an inlet passage from the pressure supply for
constantly admitting pressure to one side of said valve, and a second passage
communicating at one end with the opposite side of the valve and extending
longitudinally through the wall of the piston-chamber and opening into the
latter at a point slightly in rear of the piston when the latter is at the forward
limit of its stroke, substantially as described.
29. In a pneumatic tool, the combination of a piston-chamber open at its
rear end, a piston therein, a resetting spring for the piston, a separate valve
block secured to the rear end of the piston-chamber, for closing the same, and
containing a valve-chamber having an inlet and an exhaust port and a con-
stantly open port communicating with the piston-chamber behind the piston,
a passage from the pressure supply for constantly admitting pressure to one
side of the valve, a second passage communicating at one end with the opposite
side of the valve and extending longitudinally through the wall of the piston-
chamber and opening into the latter at a point in rear of the piston when the
latter is at the forward limit of its stroke, a check valve in said passage, and
an exhaust passage communicating at one end with the valve-chamber between
the check valve and main valve and extending longitudinally through the wall
of the piston-chamber and opening into the latter a short distance in front of the
piston when the latter is in its initial position, substantially as described.
30. In a pneumatic tool, the combination, with the piston-chamber, the valve
block fitting against its rear end and containing the valve-chamber, and the
head block fitting against the rear side of the valve block, of the separate
coupling sleeve surrounding the valve-block and connecting the piston-chamber
and head block, substantially as described.
31. In a pneumatic tool, the combination, with the piston chamber, the valve
block fitting against its rear end and containing the valve-chamber transverse
to the piston-chamber, and the head-block fitting against the rear face of the
valve block and containing the inlet and exhaust passages, of the separate
coupling sleeve surrounding the valve block and connecting the piston-chamber
and head block, substantially as described.
32. In a pneumatic tool, the combination, with the piston-chamber having a
peripheral flange at its rear end, the valve block fitting against the rear end of said
chamber, and the externally threaded head block fitting against the rear face
of the valve block, of the coupling sleeve screwed upon the head block and
having at its front end the internal flange engaging the flange upon the rear
end of the piston-chamber, said sleeve enclosing the valve block and binding it
between the head block and piston-chamber, substantially as described.

page_text: 33. In a pneumatic tool, the combination of the piston-chamber, the valve
block fitting against the rear end thereof and containing a valve chamber
transverse to the piston-chamber, said block having an inlet and an exhaust
port and a constantly open port communicating with the piston-chamber, the
head block fitting against the rear side of the valve block and having the pres-
sure supply passage registering with the inlet port of the valve block and the
exhaust passage registering with the exhaust port thercof, the reciprocating
valve in the valve chamber operating to intermittently open and close the inlet
and exhaust ports, and the coupling sleeve surrounding the valve block and
engaging a flange upon the piston-chamber at its front end and screwed at its
rear end upon the head block, substantially as described.
34. In a pneumatic tool, the combination, with the piston-chamber, the head
block, and the coupling sleeve connecting the piston-chamber and head block,
suitably engaging one and screwed upon the other, of the spring-pressed locking
key having a cam surface or rib engaging a notch or projection on the coupling
sleeve, substantially as described.
35. In a pneumatic tool, the combination, with the piston-chamber, the
valve block fitting against its rear end, the head block fitting against the rear
face of the valve block, and the coupling sleeve engaging the rear end of the
piston-chamber and screwed upon the head block, of the spring-pressed locking
key having the cam surface or rib engaging a notch or projection on the coupling
sleeve, substantially as described.
36. In a pneumatic tool, the combination, with the piston-chamber having a
peripheral flange at its rear end, the valve block fitting against the rear end of said
chamber, the head block fitting against the rear face of the valve block, and the
coupling sleeve screwed upon the head block and having at its front end an
internal flange engaging the flange upon the piston-chamber, of the spring-
pressed sliding locking key fitting in a guide-way in the piston-chamber and
head block and having the cam surfaces or ribs engaging projections or notches
on the coupling sleeve, substantially as described.
37. In a pneumatic or similar hand tool the combination, with two connected
members, one screwed to or upon the other, of a spring-pressed locking key
fitted in a guide-way in one moment and engaging the other member and
exerting a stress upon the latter tending to turn it and screw the members
more tightly together, substantially as described.
38. In a pneumatic or similar hand tool, the combination, with two con-
nected members, one screwed to or upon the other, of a spring-pressed sliding
key fitted in a guide-way in one member and having a cam-surface or rib
engaging a notch or projection on the other member and tending to turn the
latter and screw the two members more tightly together, substantially as de-
scribed.
39. In a pneumatic or similar hand tool, the combination, with two connected
members, one screwed to or upon the other, and a coupling sleeve engaging one
and screwed upon the other, for connecting them, of a spring-pressed locking
key confined in a guide-way in one or both members and engaging the coupling
sleeve and tending to turn the latter and screw it more tightly upon the threaded
member, substantially as described.
40. In a pneumatic or similar hand tool, the combination, with two connected
members, and a coupling sleeve engaging one and screwed upon the other, for
connecting them, of a spring-pressed sliding key fitting in a guide-way in one
or both of said members and provided with a cam surface or rib engaging a
notch or projection on the coupling sleeve and tending to turn the latter and
screw it more tightly upon the threaded member, substantially as described.
41. In a pneumatic or similar hand tool, the combination of two members, one
externally threaded and the other provided with a peripheral flange, a coupling
sleeve having an internal flange engaging the flanged member and internally
threaded to screw upon the other member, and a spring-pressed sliding key fitting
in a guide-way and having a cam surface or rib engaging notches or projections

page_text: on the coupling sleeve and tending to turn the latter and screw it more tightly
upon the threaded member, substantially as described.
42. In a pneumatic tool, the combination, with the tool proper, of a grasping
handle secured thereto and having the pressure supply duct extending through
it, a throttle valve in the handle for controlling said duct, and a lever confined
in a recess in the handle for operating said valve and projecting outside the
recess at one end into position to be pressed by the hand of the operator, sub-
stantially as described.
43. In a pneumatic tool, the combination, with the tool proper, of a grasping
handle secured thereto and having the pressure supply duct extending through
it, a throttle valve in the handle for controlling said duct, and a spring-pressed
lever pivoted in a recess in the handle for operating said valve and normally
acting to close it, said lever projecting outside the recess at one end into position
to be pressed by the hand of the operator, substantially as described.
44. In a pneumatic tool, the combination, with the pressure supply passage, of
a valve-chamber formed therein, a flexible tube fitted in said chamber, a tubular
locking plug or collar screwed into the valve-chamber at one end and entering
the flexible tube, to hold the latter in position, a sliding plunger moving trans-
versely of the chamber and adapted to collapse the tube to close the passage and
a spring pressed lever for engaging said plunger for operating the same and nor-
mally holding the plunger in position to close the valve, substantially as described.
45. In a pneumatic tool, the combination, with the pressure supply passage, of
a valve-chamber formed therein, a flexible tube fitted in said chamber and pro-
vided with a peripheral flange abutting against an annular shoulder, a screw
collar for clamping the flange against said shoulder, and means for collapsing
the tube in the chamber to close the valve, substantially as described.
46. In a pneumatic tool, the combination, with the pressure supply passage, of
a valve-chamber formed therein, a flexible tube fitted in said chamber and pro-
vided at one end with a peripheral flange abutting against an annular shoulder
at the end of the chamber, a tubular collar screwed into the bore at said end of
the chamber and operating to clamp the flange of the flexible tube against said
shoulder, and means for collapsing the tube to close the passage through the
chamber, substantially as described.
47. In a pneumatic tool, the combination of the piston-chamber, the valve
block fitting against its rear end, the head block fitting against the rear
face of the valve block, the handle formed integral with the head block and com-
posed of the body and neck portions, and the coupling sleeve surrounding the
valve block and connecting the piston-chamber and head block, substantially
as described.
48. In a pneumatic tool, the combination of the piston-chamber having the
peripheral flange at its rear end, the valve-block fitting against the rear end of
the piston-chamber, the externally threaded head block fitting against the rear
face of the valve block, the grasping handle formed integral with the head block
and composed of the body and neck portions, and the coupling sleeve screwed
upon the head block and provided with the internal flange engaging the flange
upon the piston-chamber, substantially as described.
49. In a pneumatic tool, the combination of the piston-chamber having the
peripheral flange at its rear end, the valve-block fitting against the rear end of
the piston-chamber, the externally threaded head-block fitting against the rear
face of the valve block, the grasping handle formed integral with the head block
and composed of the body and neck portions, the coupling sleeves screwed upon
the head block and provided with the internal flange engaging the flange upon
the piston-chamber, and the spring-pressed locking key fitting in a fixed guide-
way and having a cam-surface or rib engaging the coupling sleeve and tending
to turn the same and screw it more tightly upon the head block, substantially
as described.
50. In a pneumatic or similar hand tool the combination, with a coiled spring
held at one end from turning, of a nipple attached to its opposite end, and a
screw co-operating with said nipple to regulate the tension of the spring, one of

page_text: said members having a nick or groove and the other a co-operating rib or pro-
jection yieldingly engaging each other, substantially as described.
51. In a pneumatic or similar hand tool, the combination, with a coiled spring
held from turning at one end, of a nipple secured to the opposite end of the
spring, and a screw acting upon said nipple to regulate the tension of the spring,
said screw and nipple having engaging surfaces which yieldingly hold the screw
from turning, substantially as described.
52. In a pneumatic or similar hand tool the combination, with a coiled spring
confined in a bore and held from turning at one end, of a nipple secured to the
opposite end of said spring, and a screw plug screwed into the bore and acting
upon the nipple to regulate the tension of the spring, said plug and nipple having
engaging surfaces which yieldingly hold the plug from turning, substantially as
described.
53. In a pneumatic tool, the combination, with a coiled spring fitted in a bore
and held from turning at one end, of a nipple secured to the opposite end of said
spring and provided with a nick or rib, and a screw plug screwed into said bore
and provided with a rib or nick to co-operate with the nipple, substantially as
and for the purpose described.
54. In a pneumatic or similar hand tool, the combination, with a spring and a
tension-regulating screw therefor, of a member interposed between the spring
and screw and held from turning, said member and screw having engaging sur-
faces which yieldingly hold the screw from turning, whereby loosening of the
screw by shocks and jars is prevented, substantially as and for the purposes described
55. In a pneumatic or similar hand tool the combination, with a coiled spring
fitting in a bore, and a screw for holding the same in place, of a member fitting
in said bore and held from turning, and having a yielding engagement with said
screw, whereby loosening of the screw by shocks and jars is prevented, sub-
stantially as and for the purpose described.
56. In a pneumatic tool, the combination of the casing 16 formed of a single
piece of metal and containing the piston-chamber open at its rear end and having
the reduced bore 20 in its front end, the shouldered bushing 19 driven from the
interior of the piston chamber into the bore 20, with its shoulder abutting
against the end of the chamber, the piston 17 having the reduced front end, the
coiled spring 21 interposed between the piston and front end of the chamber
and surrounding the reduced end of the piston at one end and the bushing 19 at
its other, and an automatic valve mechanism controlling the admission of pressure
to and its exhaust from the rear end of the piston-chamber behind the piston,
substantially as described.
57. In a pneumatic tool, the combination of the casing 16 containing the
piston-chamber open at its rear end, the piston 17 in said chamber, the coiled
spring 21 confined in the chamber in front of the piston, the valve block 23
secured to the rear end of the casing and closing the open rear end of the piston-
chamber, said valve block having a valve-chamber transverse to the piston-
chamber and provided with the inlet port 37 and exhaust port 40 and the con-
stantly open port 38 communicating with the piston-chamber behind the piston,
the reciprocating valve in said chamber, the passage from the pressure supply
for constantly admitting pressure to one side of said valve, and the inlet and
exhaust passages controlled by the piston and intermittently admitting pressure
to and exhausting it from the opposite side of said valve, substantially as described.
58. In a pneumatic tool, the combination of the casing 16 containing the
piston-chamber open at its rear end, the piston 17 in said chamber, the coiled
spring 21 confined in the chamber in front of the piston, the valve block 23
secured to the rear end of the casing and closing the open rear end of the piston-
chamber, said valve-block having a valve-chamber transverse to the piston-
chamber and provided with the inlet port 37 and exhaust port 40 and the con-
stantly open port 38 communicating with the piston-chamber behind the piston,
the reciprocating valve in said chamber, the passage communicating with the
pressure supply for constantly admitting pressure to one side of said valve, the
passage communicating with the opposite side of the valve and extending longi-

page_text: tudinally through the wall of the casing 16 and opening into the piston-chamber
at a point in rear of the piston when the latter is in its forward position, the check
valve in said passage, and the second passage communicating with the valve-
chamber between the check valve and main valve and extending forward through
the wall of the casing 16 and opening into the piston-chamber at a point in front
of the piston when the latter is in its rearmost position, substantially as described.
59 In an automatic valve mechanism for pneumatic and similar hand tools,
the combination of the valve-chamber 34 having the inlet port 37 and exhaust
port 40 and the constantly open port 38, the reciprocating valve 39 fitting in
said chamber and having the flanged ends and the central chamber 57, the cylin-
drical projection 56 fitting in the chamber 57 and containing a passage for the
constant admission of pressure to the chamber 57, the passage 45 for the inter-
mittent admission of pressure to the upper side of the valve 39, the check-valve 46
at the lower end of said passage, and the exhaust passage 50 communicating
with the valve-chamber between the check valve 46 and the main valve 39, sub-
stantially as described.
60. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination of the valve block 23 containing the cylindrical valve-chamber 34,
the plugs 35 and 36 closing the upper and lower ends of said chamber, the
ports 37, 38, and 40 in the walls of the valve-chamber, the reciprocating valve 39
fitting in said chamber and having the flanged ends and the central chamber 57,
the vertical extension of the block 36 having the cylindrical upper end fitting
in the chamber 57, and the passage 58 for the constant admission of pressure to
said chamber, the passage 45 in the plug 35, controlled by the piston in the piston
chamber, for the intermittent admission of pressure to the upper side of the
valve 39, the spring-pressed check-valve 46 carried by the pendent stem 47 of
the plug 35 and co-operating with the lower end of the passage 45, and the
exhaust passage 50 controlled by the piston and communicating with the space
between the check valve 46 and the upper side of the valve 39, substantially as
described.
61. In a pneumatic tool, the combination of the casing 16 containing the
piston-chamber open at its rear end, the valve block 23 fitting against the rear
end of said casing, said block consisting of a front plate and a rearwardly pro-
jecting rectangular portion containing the valve-chamber, the head block 26
fitting against the rear side of the valve block and provided with the recess
embracing the rearward projection of the valve block, and the coupling sleeve 24
screwed upon the head block 26 and having the internal flange at its front end
engaging the peripheral flange 25 upon the rear end of the casing 16, sub-
stantially as described.
62. In a pneumatic tool, the combination of the casing 16 containing the
piston-chamber open at its rear end, the valve block 23 fitting against the rear
end of said casing, the head block 26 fitting against the rear face of the valve
block, the coupling sleeve 24 screwed upon the head block and having the inter-
nal flange engaging the peripheral flange 25 upon the rear end of the casing 16,
the locking key 27 fitting in a guide-way formed in the block 26 and wall of the
casing 16 and passing through the valve block 23, said key having the cam sur-
faces 32 co-operating with the notches 33 upon the flange of the coupling sleeve,
and the spring 29 bearing against the key 27, substantially as described.
63. In a pneumatic tool, the combination, with the tool proper having the head
block 26 secured to its rear end, of the handle formed integral with said head
block and composed of the grasping portion 60 and the curved neck portion
connecting it with said block, the pressure supply passage 53 extending through
the grasping portion and neck of the handle and through the head block, the
valve-chamber 61 formed in said passage, the flexible tube 63 confined in said
chamber, the sliding plunger 73 movable transversely of the valve-chamber to
close the valve, and means within the grasp of the operator for operating said
plunger, substantially as described.
64. In a pneumatic tool, the combination, with the tool proper, of the handle
having the grasping portion 60 and containing the pressure supply passage 53,

page_text: the valve-chamber 61 formed in said passage, the nexible tube 63 ftting in str
chamber, the sliding plunger 73 for collapsing said tube across said chamber, the
lever 72 pivoted in the recess 68 in the handle and engaging the plunger 73 at
its lower end and projecting outside said recess at its upper end, and the
spring 76 acting upon said lever, substantially as described.
65. In a pneumatic tool, the combination, with the tool proper, of the handle
having a grasping portion 60 and containing the pressure supply passage 53, the
valve-chamber 61 formed in said passage, the flexible tube 63 confined in said cham-
ber, the sliding plunger 73 co-operating with said tube, the lever 72 pivoted in the
recess 68 in the handle and engaging the plunger 73 at its lower end and pro-
jecting outside said recess at its upper end, the coiled spring 76 confined in the
bore 82 and secured at its lower end to the nipple 77 embracing the edge of the
lever 72, the nipple 79 secured to the upper end of said spring and having the nick 80
in its upper end, and the screw plug 81 screwed into the upper end of the bore 82
and having the rib 83 engaging the nick 80 of the nipple 79, substantially as
described.
66. In a pneumatic tool, the combination, with the tool proper, of the handle
having the grasping portion 60 and containing the pressure supply passage 53, the
valve-chamber 61 formed in said passage, the flexible tube 63 fitted in said chamber
and having the peripheral flange at its lower end fitting against the shoulder 66, the
screw collar 64 screwed into the threaded bore beneath the valve-chamber, for
clamping said flange against the shoulder 66, the nipple 62 of the supply pipe
screwed into the lower end of said bore beneath the collar 64, and means within
the grasp of the operator for collapsing the tube 63 to close the passage, substan-
tially as described.
67. In a pneumatic tool, the combination with the tool proper, of the handle
having the grasping portion 60 and containing the pressure supply passage 53, the
valve-chamber 61 formed in said passage, the flexible tube 63 fitted in said cham-
ber and having the peripheral flange at its lower end fitting against the shoulder 66
the screw collar 64 screwed into the threaded bore beneath the valve-chamber,
for clamping said flange against the shoulder 66, the nipple 62 of the supply
pipe screwed into the lower end of said bore beneath the collar 64, the sliding
plunger 73 movable transversely of the valve-chamber to close the valve, and the
lever 72 fitted in the recess 68 in the handle and co-operating with the plunger 73,-
substantially as described.
68. In a pneumatic tool, the combination, with the tool proper, of the handle
having the grasping portion 60 containing the pressure supply passage 53, the
valve-chamber 61 formed in said passage, the flexible tube 63 fitting in said
chamber, and having the peripheral flange at its lower end, the screw collar 64
screwed into the threaded bore beneath the valve-chamber and clamping the flange
of the tube 63 against the shoulder 66, the nipple 62 of the supply pipe screwed
into said bore beneath the collar 64, the sliding plunger 73 co-operating with
the tube 63 and having the slot 75, the lever 72 enclosed in the recess 68 in the
handle and having the hook 69 by which it is hung upon the fixed fulcrum pin 70,
said lever projecting at its upper end outside the recess 68 and having the thumb-
piece 71, and the spring 76 acting on said lever to normally hold the plunger 73
in position to close the valve, substantially as described.
69. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination of the valve-chamber, the reciprocating valve 39 having the
cylindrical middle waist portion containing the chamber 57 and the cylindrical
flanged end portions, and the part 56 fitting in the chamber 57 and containing
the duct 58, substantially as and for the purpose described.
70. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination, with the valve chamber 23, having the inlet port 37 and exhaust
port 40 and the constantly open port 38, of the reciprocating valve 39 having
the middle waist portion, closed by a suitable diaphragm, and the cylindrical
flanged end portions, said valve operating when moved in one direction to open

page_text: the port 37 and close the port 40, and when moved in the other direction close
the port 37 and open the port 40, substantially as described.
71. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination, with the valve chamber 23, having the inlet port 37 and exhaust
port 40 and the constantly open port 38, of the reciprocating valve 39 having the
middle waist portion, closed by a suitable diaphragm, and the cylindrical flanged
end portions, said valve being moved in one direction by constant pressure and
in the opposite direction by intermittently admitted pressure, and operating
when moved in one direction to open the port 37 and close the port 40, and when
moved in the opposite direction to close the port 37 and open the port 40, sub-
stantially as described.
72. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination with the valve chamber having the annular seats in its opposite
ends, of the reciprocating valve 39 consisting of the cylindrical shell having the
middle waist portion and flanged ends, the latter co-operating with the annular
seats to cut off the escape of the air in front of the valve as it approaches the end
of its stroke and confine a considerable body of air within the chamber formed
by the flanged end of the valve when it has reached the end of its stroke, and
thereby cushion the valve at the ends of its strokes, substantially as described.
73. In an automatic valve mechanism for pneumatic and similar hand tools,
the combination of the valve chamber, the reciprocating valve 39 having the
cylindrical waist portion containing the chamber 57, and the cylindrical flanged
end portions, the blocks 35 36 forming the ends of the valve chamber and having
the annular seats formed in them for the flanged ends of the valve, and the
tubular extension 56 of the block 36 fitting in the chamber 57 and containing
the duct 58, substantially as described.
Dated this 16th dove of Anril 1805
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, W.C., London,
Agents for Applicant.