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Патент USA US2122398

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July 5, 1938.
L. D. HARRISON
2,122,398`
AIR COMPRESSOR
Filed June 30, 1937
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2,122,398
Patented July 5., 1938
UNITED ASTATES PATENT oFFlci:
2,122,398
Am comnasson
Laurence D. Harrison, Phoenix, Ariz.
Application 'June so, 1937, sesamo. 151,167r
s claims. (ci. zzo-_222)
My invention relates to air compressorsv of the
reciprocating type wherein air is drawnl into a
valve was positioned so that when a slight vac
uum was created it' would open, permitting air
cylinder through an intake valve and discharged - to enter the cylinder and would close Whenever
through an exhaust valve into a receiving cham
pressurewas created by the opposite stroke of the
ber, and its objects are: First, to provide a com
piston within the cylinder. Conversely, the ex- 5
pressor of the type mentioned wherein both in
haust valve was constructed so that it would open
take and exhaust valves are lmechanically oper
against the pressure of its closing spring when
' _
ated in order to secure the proper uniform action - ever pressure was created within the cylinder
thereof, regardless of working pressures; second,
10 to provide a compressor of the type disclosed
wherein the valves are mechanically operated so
that the pistons-‘may operate at speeds com
paratively much higher than the conventional
type heretofore used; third, to provide a com
15 pressor of the type disclosed wherein mechanical
means is provided to prevent or stop the action
greater than that in the receiving tank, and
would close under this pressure and by reason of 10
its spring upon the down or outer stroke of the
piston. When pressure had been suillciently
vbuilt up within the receiver, action of the com
pressor was stopped, by holding open the intake
valve by mechanical lever arrangement. 'I'his 15
practice necessitated the use of heavy, large and
of said compressor when desired; fourth, to pro
slow moving parts in order to furnish compressed
vide a compressor of the type described wherein
air in volumes desired for commercial purposes,
leaks around the mechanically operated exhaust
20 - valve are prevented; ñfth, to provide a device of
the kind disclosed wherein strain on the exhaust
valve due to thepressure built up in the receiver
since it is impossible to operate these automatic
valves beyond a certain speed d'ue to their inertia, 20
etc.
This was particularly true ofthe exhaust valve.
tank is equalized whereby the exhaust valve is _ If, on the other hand, this valve was made lighter
not placed on a strain such as to cause its frac
ture whenoperated at high speeds; and, sixth,
- to provide mechanism associated with a com; c
pressor of the type described wherein the exhaust
valve opens only after a predetermined pressure
has been- built up in the working cylinder. Other
30 objects will appear hereinafter.
_
'
I attain these objects by means of the particular
to minimize the inertia, it was found in practice
that it soon hammered itself out of its seat or be- 25
came entirely broken or crystallized and subject
to breakage. This same condition was true of the
intake valve to a lesser degree. Due to this draw
back, therefore, it was necessary for air com
pressors to have a large piston displacement and 30
operate at comparatively slow speeds, hardly ever v
design and construction of the compressor illus
trated in the accompanying drawing herewith
exceeding 900 R. P. M.
made a part of this application in which-Fig. 1
furnish an equal volume of air compressed to the
'
,
.
In order to provide mechanism which would
is a vertical'mid-section- of the upper portion of a ' required pressure, I have provided ` the mech- 35
compressor head embodying my improvements, >anism hereinafterdescribed, and illustrated in
taken on a plane parallel with the’axis'of the the accompanying drawing, in which the valves
crank shaft; Fig. 2 is a plan view of the cylinder , are caused to--operate mechanically and, there
head, as shown in Fig. 1, with the cam lifting fore, can be made much heavierand larger in
mechanism shown in section; Fig. 3 is a «vertical order tó stand the strain to which they are subsection taken substantially on line #-4,
2;
ject and since these valves do not depend upon
' Fig. 4 is a vertical section taken substantially on differences~ of air pressure to cause them to oper
line 4_4, Fig. 2; Fig. 5 is a diagrammatic eleva - ate, they may be timed to open and close at the
tion of a cylinder showing the crank'and cam desired positions ofthe piston and to open sum
mechanism; and 1""ig.l 6 is a modified form, in ciently to provide a free unobstructed passage for
the air being pumped.
section, of an exhaust valve accordion spring.
Similar numerals refer to similar parts in all
As illustrated in theaccompanying drawing, 2
views.
,
‘
designates the top end of the cylinder, 3 the cylin
Heretofore the practice has been to construct der head, l the intake valve and 5 the exhaust
50 air compressors 'with both valves operating auto
matically from the pressures created by differ
.These valves are seated in the usual manner'in
ential air pressures created by the movement of the cylinder head provided with an intake port
valve.
_
`
,
.
40V
'
45'
50
.
the piston within the cylinder. These valves , 23 leading from the outer air, and exhaust port
were variously termed, but are commonly known
55 as weak-spring or flutter valves. The intake
2l connected to a compressed air receiver.
'
With reference to the intake valve, it will be 55 _
2
2,122,395
noted that it Vis held shut under me tension of Fig. 6, the accordion 30 may be made of setter,
spring 6 in the usual manner, and is mechanically vmetal while the assistant spring 3l is used- to
operated by the rocker arm 1, operatively mount
furnish the tension and keep the valve closed.
ed on an eccentrically positioned journal 8 on
rocker arm shaft -9. ?This rocker arm is in turn
operated by push rod I0 from cam 25, operating
at the same speed as crank shaft 35 and indicated
» Push rod 22, voperating rockervarm I6, coop
erates with-cam 26 in the usual manner. Its lift,
however, is positioned so that exhaust valve 5 is
'
notV opened until the upwardly traveling piston
diagrammatically in Fig. 5.
>321'1has approached the upper end of its-stroke as
Exhaust valve 5 is iitted within the head 3 the shown in Fig. 5 and has compressedï'the air in the
10 same as the Vintake valve, which is opposite 'to
Ithe conventional manner in which exhfaust valves
of air compressors are positioned. Itíis held shut
under the tension of the spring steel accordion
y »bellows I2, which is attached to the upper part
15 of the valve stem by: an air-tight seal Il3 and to
cylinder to a predetermined pressure approxi 1.0
mately equal to that to be maintained in the re
ceiver. Thus, after a charge is drawn in and
compression started, lthe only pressure against
the upwardly traveling piston is that of the .com
pression ef the charge just received, until »it
slightly exceeds the working pressure andcthe
valve opens. Therefore, the piston does not have
to? work against the full- pressure of the receiver
the cylinderhead 3 by a similarly air-tight seal I4,
held in placeîby a large bushing I5. This exhaust
valve is operated by a rocker arm I6, operatively
supported on an eccentrically positioned journal tank throughout the whole upper stroke. L
"
.120 I ‘I on shaft 9, and operated by push ’rodi 22 from
VOperation is as followszßAir is drawn from in 20
cam 26 revolving at crank shaft speed.
' take port'23 through the intake valve, operated
Shaft 9 is rotatably supported and journaled to by a cam timed to lift so that it fully opens soon
turn in support brackets I8, attached to cylinder after the commencement of the intake stroke and
head 3. It is provided at one end with a bell stays open until? the piston »has practically
25 crank I9, which may be operated by any con
g: 30
venient leverage means to swing through an
arc-.of approximately 90°. It is to be noted that
theecenter ofthe journal 8 on which the rocker
arm ‘I is mounted is'oppositely positioned to Ythat
of the journal 'I'I,'on which rocker arm i6 is
.mounted
reached the bottom of its travel.
On the up
stroke the intake valve closes and the exhaust
valve remains closed until the piston reaches a
point, as above stated, where the Vpressure in the
cylinder approximates that to be ?maintained in
the receiver. At this p<:-int,the> exhaustL valve 30
When the shaft â is in the neutral'po- _ opens and remains open until -the piston reaches
sition, as illustrated in Figs. 3 and 4, both valve
tappets are operative. _ If, however, it is swung
the upper limit or?Y its travcl, when it again closes.
Now, if suilicient pressure ?has been built up in the
90° in the directionìof the arrow, it ewill be noted
35 that the journal axis of rocker arm-'I is lowered.
receiver, _and it is desired to momentarily stop
This has the eiïect’of holding open the intake
compressing, rocker -arm shaft 9 is rotated'
throughout approximately 90° in theV direction of
valve. On the other hand, eccentric I1, support- . the arrows in Figs. 3 and 4. This shifts ?the po
ing the exhaust valve rocker arm, is raised so that
sition ofV4 .both of the eccentric portionsßf the
the rocker arm does not operate the valve which,
therefore, ¿remains closed. By rotating this
rocker arm shaft 9, as above explained, and
causes the- axis of rocker arm ‘I to be lowered so 40
that it remains open even though its push rod
operates; On the other hand, the axis of rocker
arm I6
raisedso that it does not contact the
rocker arm shaft the operation of'these valves
may be regulated ¿and the device caused to idl'e,
although the shaft and piston may continue to
rotate. _Air will be pumped in and -out of the etop `of the stem of valve 5, although it continues
intake manifold. but air pressure will be main ¿to ride in operative position o_n its push rod by
" tained in the receiver by reason of the inoperation Yreason of the tension of spring ¿38. This simple
of;V the closed exhaust valve. This construction and eñîecti-ve means permits the regulation of the
also avoids the_possibility of the compressor stop
Vpressurein the receiverä and bell crank I9 may
ping ata point with the exhaust valve open, which be operated through any convenient lever system
would cause a loss of pressurefrom the receiver «either manuallye or by a pressure _regulating ac 50
ordamage to the drivingY machinery by reason cordion; diaphragm connected with the receiver.V
lof ka back .motion of the piston. RockerV arm
springs 21 and 23 are connected between the
Since both valves operate mechanically at a
cylinder head and the rocker arms ‘I and I6 re
predetermined timed position, and the tension of
spectively, to causethese arms to remain Éin op Y their springs may be sumcient toîmake a closure at?
erative position on, or ride, the upper endsof Y all times, itis obvious that this type of mechanism
the push rods, regardless of the position of th
is not hampered by inertia which limits the speed
tank.
`rocker arìn shaft or its movements.
'
e
Y
Y
'e
Vof automatically operated valves. For this rea
The accordion spring Iâ is made with sufñcient son, an air compressor provided with my valve A
tensionto hold the exhaust valve 5V'closed, against - mechanism may be made of much smaller size, 60
any predetermined pressure in the receiver. Air andV by increasing'its crank shaft speed, wiil
pressure from exhaust port 24 enters the closed i easily deliver the -samevolume of air atthe same
chambern20, through vent opening 29 and, press- Y., pressure as the heavier and more bulkyïcompres
' ing outwardly, tends to offset the pressure exerted
V,against the valve disk 2I, which tends to open it.
Therefore, higher pressure thannthat which the
spring would otherwise be capable of holding by
itself, may be maintained in theY receiver. The
action of the accordion valve spring, therefore is '
70 three-fold-First, it prevents pressure from leak
sors now` in general use. Whilecompresîsors' ordi
narily do not?operate at a speed greaterfthan 65
900 RIP. M., .compressors of the type here dis
closed may be operated at speeds-.as high as 3,500 .
R. P. M., thusfpermitti'ng a great saving in space -
and weight, as'?well as‘makingit more economical
?ing fromthe receiver out throughthe valve-stem;
in maintaining'valves in “good condition.
70
I wish to be limited only by the following
second, it operates as an offsetchamber to equal-lY
claims.
-j
'
e'
ize the pressure on the valve disk and assist inYY
I claim:
'
_
_
,
Y¿maintaining it- closed; and, third, it acts as a,
1.‘Va.lve mechanism for air Ycompressors of the
‘Il valve spring. In the alternative form shown in reciprocating piston type comprising. incombina 75
2,122,398
3
tion a cylinder head lbeing ported and provided
distance whereby to shift the axes of said eccen
with valve seats for an intake and exhaust valve
trically positioned rocker arm journals.
4. Valve mechanism for reciprocating air com
take and exhaust -valves seated therein having pressors comprising a' cylinder head provided
their- stems protruding outward from said cyl
with an intake port and exhaust port'and valve Ul
inder head, a helical spring intermediate said cyl
seats communicating therewith to receive in
inder headand the outer end of said intake valve, wardly opening poppet valves, an intake valve
an accordion spring intermediate said cylinder operative in said intake port valve seat having its
head and the outer end of the stem of said exhaust stem protruding outwardly through said cylinder
10 valve, means for sealing. said accordion spring to . head and a spring normally holding said valve 10
the cylinder head and the place of its attachment shut intermediate said cylinder head and the
on the stem of said exhaust valve respectively, outer end of said valve stem, an exhaust valve
rocker arms adapted to operatively open said seated in said exhaust valve port seat havingl an
outwardly extending stem, a spring consisting of
valves supported on the rocker arm shaft at
tached to said cylinder head with the journal a resilient accordion cylinder> annularly sur
rounding said exhaust valve stem and provided
supporting said intake valve eccentrically posi
' _to open inwardly into said cylinder chamber, in- ‘
tioned relative to the axis of said rocker arm shaft
and the journal supporting said exhaust valve
rocker arm eccentrically positioned relative to the
20 axis of said rocker arm shaft, the axes of said
eccentrically positioned journals being oppositely
» positioned relative tothe axis of said rocker arm
with an air tight seal at its outer end to the outer
end of the valve stem of said exhaust valve and a
seal at its lower end forming an air-tight closure
to said cylinder head, together with mechanism 20
for alternately operating said valves at predeter
mined intervals comprising rocker arms, push
rods and cams operatively associated with the
shaft, push rod mechanism for alternately oper
ating said valve, and means for axially rotating crank shaft of said compressor, said rocker arms
25 said rocker arm shaft throughout a predeter ' being supported on a rotative rocker arm shaft 25
and having bearings operative on journals eccen
mined arc.
.
trically positioned relative to the axis of said
2. Valve mechanism for reciprocating air com
pressors comprising a cylinder head provided ~rocker arm shaft, the centers of said eccentric
with an intake port and'exhaust port and valve journals being disposed at uniform distances on
either side of the axis of said rocker' arm shaft,
30 seats communicating therewith to receive in
wardly opening poppet valves.. an intake valve and means for rotating said rocker arm shaft a
operative in said intake port valve seat having its l predetermined distance whereby to shift the axes
' stem protruding outwardly through lsaid cylinder of said eccentricaily positioned rocker arm jour
head and a spring normally holding said valve
5. In a reciprocating air compressor, valves and 35
35 shut intermediate said cylinder head and _the
outer' end of said valve stem, anexhaust valveY associated'mechanism comprising inwardly open
seatedvin said exhaust valve port seat having an ing poppet intake and exhaust valves communi
outwardlyI extending stem, a spring consisting of
a resilient accordion cylinder annularly surround
40 ing said exhaust valve stem and provided with an-
air-tight seal at its outer Aend to the outer end of
the valve stem of said exhaust valve and a seal
at its lower end forming an air-tight closure tov
said cylinder head, together with mechanism for
45 mechanically operating said valves at predeter
mined intervals. v
3. Valve mechanism for reciprocating air com
pressors comprising a cylinder head provided with
an intake port and exhaust port and valve seats
communicating therewith to receive inwardly
opening poppet valves, an intake valveoperative
eating with `the compressor cylinder, positive
means for opening said valves at _pre-determined
intervals, including rocker arms, push rods and
cams operative from the compressor crank shaft,
a combined valve closing spring and sealing means
vsurroundingr the exhaust valve stem adapted to
prevent leakage from the compressed air receiver
back through the valve stem chamber, and pas
sageways communicating air pressure from said
receiver to said sealing means whereby back
pressure froni4 said receiverl pushing outward
tends to hold said inwardly opening exhaust valve _
closed.
4
_
,
.
6. In a reciprocating air compressor, valves and
associated mechanism comprising inwardly open
ing poppet intake and exhaust valves communi
cating with the compressor cylinder, positive
a spring normally holding said valve shut inter
55 mediate saidcylinder head and the outer end of Ämeans for opening said valves at pre-determined
said valve stem, an exhaust valve seated in said intervals, including vrocker arms, push rods and
_ in said intake port .valve seat having its stem pro
truding outwardly through said cylinder head and
exhaust Avalve port seat having an outwardly ex _ cams operative from the compressor crank shaft,
tending stem, a spring consisting of a resilient a combined valve closing spring and sealing
accordion cylinder annularly surrounding said
60 exhaust valve stem and provided with an air
tight seal at its outer end to the outer end of the
valve stem of said exhaust valve and a seal at its
lower end forming >an air-tight closure to said
cylinder head, together with- mechanism 'for al
means
surrounding
the
exhaust
valve
stem "
adapted to prevent leakage from the compressed
air receiver back through the valve stem cham
ber, land passageways communicating air pres
sure from said receiver to said- sealing means '
whereby back pressure from said receiver push
ternately operating- said valves at predetermined ` ing outward tends to hold said inwardly open-v
intervals comprising rocker arms, push rods and ing exhaust valve closed, together- with means
cam-operatively associated with the crank shaft for rendering said valves inoperative by holding
of said compressor,_said rocker arms being sup
ported on a rotative rocker arm shaft and having
said intake valve open and permitting said ex- _
bearings operative on journals eccentrically posi
able rocker arm shafthaving eccentrically posi
haust valve to remain closed, comprising a rotat
tioned relative to the axis of said rocker arm ltioned rocker arm journals thereon with their
shaft, the' centers of said eccentric journals being
eccentric centers substantially oppositely posi
disposed at uniform distances on either side of ‘ tioned relative to the axis of said rocker a
the axis of said rocker arm shaft, and means for
-rotating said rocker arm shaft a predetermined.
shaft.v
‘
LAURENCE D. HARRISON.
Il
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