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Патент USA US2406747

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Sept. 3, 1946.
E. w. DAVIS
, 2,406,747
PNEUMATIC MOTOR
Filed Ju'ne‘15,_ 1945
2 Sheets-Sheet 1v
Sept- 3, 1946- .
E. w.'DAv|'s
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‘PNEUMATIC MOTOR v'
' ' Filed June 15, 1945
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Patented Sept. 3, 1946
2,406,747
UNITED STATES PATENT‘ OFFICE
‘
2,406,747
‘
PNEUMATIC MOTOR
Ernest W. Davis, River Forest, vIll.
Application June 15, 1945, Serial'No.y'599,664
4 Claims.
-
(Cl. 121-164)
1
2
7 My invention relates generally to pneumatic
motors, and more particularly to improved valve
mechanisms therefor.
improved pneumatic pressure operated recipro
end of the cylinder bore 58.
cating motor having an improved valve mecha
‘
A further object is to provide an‘ improved
balanced valve mechanism for pneumatic motors.
A further object is to provide an improved 10
pneumatic motor which is simple in construc
tion, reliable in operation, and which may be
economically produced.
Other'objects will appear from the following
description, reference being had to the accom
panying drawings, in which:
Fig. 1 is a central vertical sectional view of
the improved lubricant compressor and pneu
matic motor;
Fig.- 2 is a plan view thereof:
Fig. 3 is an enlarged fragmentary sectional
view of the valve mechanism, showing the posi
tions of the valves during the downstroke of the
motor piston; and
.
head being provided with a passageway 54 lead
ing from a lower valve chamber 56 to the upper
It is an object of my invention to provide an"
nism.
i
A cylinder head 52 is suitably secured to the
upper end of the cylinder body casting 34, this
The head 52 also
has a passageway 60 leading from an upper valve
chamber 62 to the lower end of the cylinder‘
bore 56 through a connecting passageway 64
formed in the pump body casting 34.
The body casting 34 has a sidewardly extend
ing ?ange portion 66 provided with a valve seat
68. ‘A second valve seat 10 is formed between
the lower valve chamber 56 and upper valve
chamber 62. The upper valve chamber ‘is thread
15 ed to receive a cylindrical bushing 12.
The valve assembly comprises a poppet type
- valve 14, for cooperation with the valve seat 68,
and a secondpoppet valve 16, for cooperation
with the valve seat 'Hl.v The valve 14 is pref
20 erably formed integrally with a valve stem 86,
while the poppet valve 16 is clamped against a
shoulder on the valve stem 86 by a sleeve 82
threaded on the upper end of the stem 80.
A 1
'
cup leather piston 84 is slidable in the bore of
Fig. 4 is a similar view showing the positions 25 the cylinder bushing 12 and is clamped between
of the valves on the upstroke of the piston.
the sleeve 62 and nuts 86 threaded on the upper
Referring to Fig. 1, the airmotor is illustrated
end Of the valve stem 80.
as forming a part of a lubricant ‘pumping mech
The valve stem 80 is guided for longitudinal
anism customarily termed a “barrel pump,” since
sliding movement in a bushed boss 88 forming
it is adaptedto remove oils and greases from
part of the pump body casting 34. The lower
barrels and drums in which the lubricants and
end portion 90 of the stem 80 is of reduced diam?
similar products are shipped. This compressor
eter and has a pair of helical springs 92, 93 held
is shown as comprising a cylinder I6 which is
thereon, the spring 92 operating to transmit
. secured to a cover I2 of an oil drum M, the
force from the arm 42 to an adjustable stop 94
cylinder l0 extending to the bottom of the drum 35 on the valve stem, while the spring 93‘is adapted
and having inlet ports l6 normally closed by a
to transmit force from the arm 42 to an adjust
foot valve I 8. A piston 20 is reciprocal in the
able stop 96.‘
cylinder l0 and is secured to a piston rod 22.
The operating ?uid is supplied to the upper
Ports 24 in the piston 26 are adapted to be closed
valve chamber 62 through an inlet pipe 98 pro
on the upstroke of the piston by a check valve 40 vided with a shutoif valve I66.
26. The piston rod extends through a head 28
In using the apparatus, the operating ?uid,
at the ‘upper end of the barrel Ill, a suitable
such as compressed air, is supplied to the upper
packing'gland 30 being provided. The lubricant
valve chamber 62 upon opening the shutoff valve
is discharged from the barrel l6 through a pipe
32.
A motor cylinder body 34 is preferably cast
integrally with pedestals 36 which have foot per
tionsp38 clamped to the end of the barrel ID by
I00. Assuming that the valve assembly and pis
ton 48 are in the positions shown in Fig. 1, the
air under pressure will flow past the poppet valve
62 into the lower valve chamber 56, which is
_ always in communication with the upper end of
cap screws 40, which also secure the head 28 to
the cylinder 58. Thus air under pressure will be
the'end of the barrel. ‘A valve actuating arm 42 50 supplied to both the upper and lower ends of the
is clamped against a shoulder 44 formed on the
cylinder 53, since it is clear that the lower end
piston rod 22 by a. sleeve 46. > Against the upper
of this cylinder is at all times in communication
end of the latter there is clamped apiston 48,
the-clamping being effected by a nut 50 threaded
at the upper end of the‘rod 22.’
"
'
with the upper valve chamber. However, due to
the fact that the sleeve 46 is of substantial cross
sectional area, it will be apparent that the effec
2,406,747
a
O
tive area of the upper surface of the piston 48
is much greater than that of its lower surface,
and therefore the piston 48 will be moved down
wardly under the in?uence of the difference be
tween the forces applied to its upper and lower
surfaces by the compressed air. Upon down
ward movement of the piston 48, lubricant con
tained within the lower end of the barrel II)
will ?ow through the ports 24 of the piston 20,
raising the check valve 26, and some of them 10
bricant will be discharged through the pipe 32,
due to its displacement by the portion of the
piston rod 22 which enters the barrel I0. When
the piston 48 approaches the end of its down
stroke, the arm 42 will engage the spring ‘93 and
compress the latter until sui?cient ‘force is applied
to the valve stem 80, 90, to snapthe valve assem
bly from the position in which it is shownin
Figs. 1 and 3 to the position in which it is shown
in Fig. 4.
_
vIt will be noted that when the valveis in the
position of Figs. 1 and 3, the pressure of the oper
ating ?uid is exerted'on the balancing cup leather
piston 84' as well as over thee?ective area of the
valve 14., However, because the diameter of the
piston ,84 isgreater than that of the valve ‘14, the
operating ?uid will apply a net force to the valve
assembly inan Aupwarddirection.tohold it inthe
4
tent means are required to hold the valve in its
two operating positions. The dimensions of the
latter parts are such that the valve will not move
accidentally due to vibration, and yet sufficient
force is applied to hold the valve assembly in its
two operative positions so that the valve will
operate with a snap action.
Whilel have shown and described a preferred
embodiment of my invention, it will be apparent
that numerous variations and modi?cations
thereof may be made without departing from the
underlying principles of the invention, I there
fore desire, by the following claims, to include
within the scope of the invention, all such varia
tions and modi?cations by which substantially the
results of my invention may be obtained through
the use of substantially the same or equivalent
means.
I claim:
1. In a ?uid pressure operated motor, the com
bination of a motor cylinder, a motor piston re
ciprocable therein, a piston rod of substantial ef
fective cross sectional area with respect to that
of the piston, and valve means forcontrolling the
supply of ?uid to the opposite ,ends of said
cylinder, said valve means comprising two cham
bers respectively in communication with opposite
ends of said cylinder, “a ?rst valve seat providing
a relatively small diameter outlet port, leading
position in which it .is shown in Figs. 1 and 3.
However, as the spring v93 becomes compressed 30 fromvthe ?rst of said chambers to the atmosphere,
further toward the endof the downstroke of the
motor piston 43, the force of the compressed air
holding .the .valve assemblyin its upper. position
will be overcome; As soon as the valve 14 leaves
its seat, the, pressure inthe vlower valve chamber
5\_6_will drop and the force of thecompressed air
acting Qntopoi the poppet valve ‘it, as well as
a second valve seat intermediate said valve cham
bers, the other of said chambers having a cylin
drical bore open to the atmosphere, said bore
being of slightly less cross sectional area than
\ said second valve seat, and being of substantially
greater cross sectional area than said ?rst valve
. seat, a valve assembly having poppet valves re
spectively coo-perable with said valve seats andv
the force, of the compressed spring. 93, will be
having a piston reciprocable in said cylindrical
effective rapidly to snap the valve assembly from
the position shown in Figs. 1 and 3, to the posi 40 bore, and means operated by said motor piston to
move said valve assembly in the direction of
tion shown in Fig. 4.
piston movement ‘near the end of each stroke of
Whenthe valve mechanism is in the position
the motor piston.
shown in Fig. 4, air under pressure ?ows from
v21A valve vmechanism for fluid operated re
the upper valve chamber 62 through the passage
ciprocating piston and cylinder type'motors com
way 6,0, 6,4, to the lower end of. cylinder. 58.
prising, means ‘forming a pair of valve chambers
thesame time‘, the air in the upper end of the
cylinder 58 is free to escape tolthe atmosphere
through passageway .54, loWer. valve chamber 56,
andthrough the port at the valve seat 68.
; It will be noted that the effective area of the
poppet valve 16 and of its seat. 10 is slightly
greater than that. of. the bore in the cylinder
bushing 12, andthus the air will exertv a net. down
ward pressure onthe valve assembly. This pres
surewill be suj?icient to holdthe valveassembly.
in the position in which it is shown in Fig. 4.
Thus the motor piston 48 will be moved upwardly.
During the upward stroke, the lubricant pump
communicating with the opposite ends of the
motor cylinder, having a ?rst valve seat inter,
med-iate the chambers, a balancing piston having
one side thereoi exposed to pressure in one of said
valve chambers and having its other side ‘exposed
to atmospheric pressure, a second valveseat form
ing' an air outlet port leading from the other of
said'valvechambersto the atmosphere, a second.
valve rigidly. connected: to said ?rst valve and to,
said‘piston and cooperable with said second valve
seat, said valves operating in opposite directions.
and spaced so that when'one valve is closed the.
valve 26 closes and the lubricant above'the piston
otherisifully opened.
cision, and due to the successive decreases in
diameter; of the valve seat, 1!}, the bore of the,
the atmosphere. a valve assembly ‘comprising a.
piston member slidable in the cylindrical bore,.a.
poppet valve c00perab1e;with..tne yalve.s.eat,_.and
2|] is discharged through the pipe 32. Also dur 60 '3."In a. valve mechanism for a ?uid operated
motor having acylinder anda piston reciprocable
ll'lg this upward stroke, the foot valve 16 opens
therein, a valve. body providingv a ?rst chamber
to admit lubricant. As the piston 48 reaches the
and a second chamber, means; connecting the ?rst
upper end ofv its stroke, the spring 92 is brought
chamber to a source of ?uid under ‘pressure,
into-engagementwith the adjustable stop 94 and
means respectively connecting said chambers tov
compressed until it applies su?icient force to the
the opposite ‘endsof the motor cylinder, the ?rst
valyestem 89,90, to move thelatter to its upper
of said chambers having a cylindrical bore’ lead
position, as shown in Figs. 1 and 3, thus complet
ing to the atmosphere at. one side and a valve
ing a cycle of operation,
seat of_ greater diameter than said cylindrical.
Due to the fact that the valves 14 and 16 are of
the poppet type, and due to the use of the cup 70 bore at. the other side, said second valve 'cham—,.
her having an outlet port, of smaller diameter.
leather, piston 84, the valve mechanism need not
than said cylindrical, bore leadingvv therefrom to,
be manufactured with a very high degree of pre
cylinder bushing». 12.. andthe valveseat 68.110. de-,
2,406,747
5
6
a second poppet valve for closing the outlet port,
said poppet valves closing upon moving the valve
assembly in opposite direction and being spaced
the other side; said second valve chamber having
an outlet port of smaller diameter than said cylin
drical bore leading therefrom to the atmosphere;
apart so that when one valve is closed the other
a valve asssembly comprising a piston member
is opened, and means for reciprocating said valve
slidable in the cylindrical bore; a poppet valve 00
assembly in response to movement of the motor
piston near the ends of its forward and return
operable with the valve seat, and a, valve stem
secured to said piston member and said poppet
valve, said valve stem having formed thereon a
strokes.
v
4. In a valve mechanism for a ?uid operated
second poppet valve for closing the outlet port,
motor having a cylinder and a piston reciprocable 10 said poppet valves alternately closing upon mov
therein; a valve body providing a ?rst chamber
ing the valve assembly in opposite direction and
being spaced apart so that when one valve is
and a second chamber; means connecting the
?rst chamber to a source of ?uid under pressure;
closed the other is opened; and means for re
means respectively connecting said chambers to
ciprocating said valve assembly in response to
the opposite ends of the motor cylinder; the ?rst 15 movement of the motor piston near the ends of its
of said chambers having a cylindrical bore lead
forward strokes.
ing to the atmosphere at one side and a valve seat
ERNEST W, DAVIS.
of greater diameter than said cylindrical bore at
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