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Патент USA US2117863

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May '17, 193s.
4 Sheie'cs--Shemì> l
Filed Feb. 11, 1935
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May 17,» 1938.
Filed Feb. ll, 1935
4 Sheets-Sheet 5
May 11, 1938.
Filed Feb. 11, 1935
4 sheets-sheet 4
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v _I Patented/May 17, 1938
Georg Slékely, Gral, Austria
application February 11, 1935, serial'Nn. 5,916
In Austria February 26, 1934
IClaim. (Cl. 230-55)
'I‘his invention relates to electromagnetically maintained over a wider range of end pressures
driven compressors or vacuum pumps of the type
in which a resiliently mounted compressor mem
than has hitherto been the case.
ber is driven by the vibrating armature of an
5 alternating currentelectromagnet, and in which
l the entire vibrating system is tuned accurately
or approximately into resonance with the alter
nating magnetic iield which sets up and main- j
tains the vibrations of the system, and has for its
l0 object to improve the resonance conditions at a
certain output, and also to extend the range of
output within which a favorable working condi
tion prevails.
What has hitherto stood in the way of the em
15 ployment of compressors of this description has
been the drawback that the most favorable reso
nance conditions are only realized when working
to a certain definite end pressure, and that the
deflection or throw of the vibrations falls off very
20 considerably when the end pressure deviates but
_very slightly lfrom the ideal. 'I‘he present inven
tion is based upon recognition of the fact that
this disadvantageous behaviour is largely due to
the linear characteristic of the vibrating means
25 and resilient elements hitherto usual in the drive
employed» in such devices, with the result that on
alteration of the pneumatic force or resistance
there is brought about an alteration in the re
sultant spring force acting upon the vibrating
mass which is sumcient to destroy the state of
In order to overcome this unfavorable inñuenc
ing of the state of resonance conditioned by the
curvature of the compression characteristic, the
present invention proposes the employment of
spring means for the vibrating system which have
a non-linear curve for the power developed ex
. pressed as a function of the course,
It thus be
comes possible, more particularly when the char
acteristic of the spring means employed is` up
wardly curved, to bring about `a condition of
vibration which approximates far more closely
-to the character of harmonic oscillations than
does the condition of vibration set up'with the
l5 employment of springs of _linear characteristic.
Compressors constructed in accordance with the
invention thus show a more favorable state of
working, when the output is adJUsted to a certain
pressure, than the hitherto known compressors,
¿o since resonance is invariably far more easily
realized in a harmonically vibrating system than
when the vibration is non-harmonic or pseudo
harmonic. A further advantage of the invention
which is of particular importance is that the mean
`5 rise of the resultant spring characteristic changes,
less, when working to diil'ermt end pressure, with
_the employment of springs of non-linear than
with the employment of springs of linear char
acteristic, with the result, under practical work
n ing conditions, tint the state of resonance is
As springs of non-linear characteristic it is
advisable to employ conical springs which are so
made that, when stressed, the lower turns become 5
gradually applied to the supporting foundation, so
that the number of eifective turns diminishes and
the power increase is augmented per unit of de
pression. 'I'he non-linear characteristic of the g
spring means employed can, however, also be 10
obtained in other ways, for example by the use
of materials the natural resiliency of which pos
sesses the desired non-linear character, such as
is the case for example with vulcanized rubber.
A form of construction for a compressor unit 15v
in accordance with the invention is shown, by
way of example, in the accompanying drawings,- in
Fig. 1 is a sectiona1_view of the compressor
Fig. 2 isl a side view of the same taken partly
in section of Fig. 1;
Fig. 3 is a plan view of the same;
Fig. 4 shows a modiiled construction of the
spring means; `
Fig. 5 is a graphic representation of output
In the constructional example shown in Fig
ures 1 to 4 of the drawings I denotes the electro
magnet which drives the compressor, the coil 2 of
this magnet being traversed .by current derived 30
from an alternating current main and thereby
caused to exert upon the armature 3 an attrac
tion Vwhich fluctuates periodically in intensity.
The electromagnet I has a circuit in iron which
is as far as possible closed, in order to provide
maximum electromagnetic output with minimum
weight and space requirement. For this same
reason the number and size of the air gaps 4,
4', I" which interrupt the iron circuitl are keptdown to a minimum, and the same end is also 40
served by the sloping ofthe air gaps 4’ and l"
relatively to the direction of vibration of thearmature I.v
To the armature 8 is attached the lower end of
the bifurcated connecting rod 5 which is made 45
up of laminated material, and which is provided
at its upper end with the arched or cambered
base plate 6 oi' the piston. The body 1 of' the
piston, which is made of rubber, is attached to 50
this plate 6 by means of the embedded.and- vul
canized-in ring 8 and of the'clamps 9. The mar
ginal portion 'la of the body 1 of the piston is _of
Slight thickness so that it is in the nature of a
diaphragm, and is clamped, together with the re- 55
maining parts of the compressor, in a ring Ill- '
supported in the uprights Il of the framework
o! the' unit. The hitherto described parts of the
vibrating system, namely the armature 3, the
pieten l, andthe connecting rod l. should bemade f
as light as possible, in order to-reduce inertia
resistance to a minimum, and this fact is taken.
account of inthe shaping and construction oi
these parts.
The base plate 6 of the compressor piston is
resiliently supported against the stationary part
of the unit by means of a block of rubber i3
which is supported on a cross head I2 bridging
the uprights II. This rubber block I3 is a re
silient massive body of elastic material which
can be tuned to the desired frequency by suitable
shaping, and the characteristic curve of which
is non-linear and likewise capable of being ln
iluenced in a desired sense by suitable shaping
of the block. In lieu of this elastic body i3 it
is also possible to employ a tapered helical spring
tia as the supporting or bearing spring of the
vibrating system, as indicated in Fig. 4. In riesigning the springing means employed for the
vibrating piston care must also be taken to make
this spring, which likewise pertains to the total
ity of the vibrating system, as light as possible
in weight. In order to allow for compensation
of~ any alteration in the initial tension of the
25 spring means I3 or I3a which may occur in the
course of use, and thus to obviate any alteration
of the inherent frequency or characteristic of
these means, and also to admit of accurate ad
justment of the initial tension of the spring
SII means, the cross head I2 is adjustable upon the
uprlghts II by means of nuts I4.
The rubber
block I3 is prevented from shifting its position
by the provision of centering studs i5 and I5'.
by correct dimensioning of the 'stroke-limit
ing counterforces, to provide a. stroke volume
oi the compressor member which practically
completely ñlls out the working chamber of the
Over the plate i8 there are pro
vided thesuction chamber 21 with the suction
pipe connection 24, and the'compression cham
ber 25 with the compression pipe connection 26.
The hoods 2l and 2! enclosing these chambers,
respectively, are attached to the cover I6 and-to
the ring Il, respectively, and can readily be de
tached, together with the cover I6, after slack
ening of the screws 30. The electromagnet I and
the uprights II rest upon feet 3I and 32 which
are preferably made of sound- and shock-ab 15
sorbing material.
The non-linear characteristic of the spring
means associated with the piston not only im
proves the character of the vibrations, but also
helps to prevent the length of the compressor 20
strobe from being in general influenced by the
output ci* the compressor to any appreciable
extent, since the resonance once set is main
tained in the various working states of the ccm
This will be clearly understood by having ref
erence to Fig. 5 in which the ordinates give the
output of the compressor (in litres per hour)
referred to the state at suction, and the e «~
the end excess pressure (in atm.) of
pressed air. The broken line I represents the
output characteristic obtained in a` particular
case with a compressor having springing means
35 IG, which is disposed opposite the same and is
of linear characteristic; after replacement of
this spring by a spring of non-linear character
likewise clamped peripherally in the ring III,
istie there was obtained the more favorable
there is enclosed the working chamber I1 of the
compressor in which the intake, compression,
and expulsion of the working medium is eifected.
In the cover I6 there are arranged the suction
and the pressure valve of the compressor, so that
„ the vibrating piston comprises no valve parts to
add to its total mass. The employment of an
curve represented bythe full line 1I.
In Figs. 1 and 2 of the drawings there is shown
Between ‘the compressor piston 'I and the cover
independently acting suction valve'necessltates.
45 however, that its moving parts be so constructed
that they are capable of keeping up with the
rapid working rhythm of the compressor ac
cording to the invention. It is therefore advis
able to make the suction valve disk--and the
same applies also to the pressure valve disk-as
lightI as possible in weight, and to make- it of
such shape that it can open and close with the
frequency ofthe piston vibration or with even
higher frequency. In the constructional exam
the lowest position of the `vibrating system (pis
ton and armature) under- normal Working con
ditions. If under exceptional working conditions
the maximum amplitude of vibration should
happen to become exceeded, the increasing of
such a tendency beyond the admissible limit is
prevented by the lower surface 33 of the arma
ture coming in contact with the opposite sur
face 3| on the core of the electromagnet, or by
the body 1 of the piston striking against the
cover I6. Related subject matter was described
in applicant’s abandoned application Serial No.
761,140, died December 6, 1935.
I claim:
An electromagnetlcally driven compressor or
vacuum pump having, in combination, an elec
ple shown in the drawings this result is achieved
'as bythe
use of a rubber suction valve disk I8 which
tromagnet comprising a stationary magnet body,
is thickened in the middle so as to be of lentil
alternating electrical current of given frequency
shape, and the marginal portion of which covers
over theV suction apertures I9 provided in the
cover I6. The'suction valve c_lisk I8 is attached
and a vibratile armature in position to be at
in position, the clearance, provided the stroke
of the piston is suillciently long, is reduced to a
conical helical spring arranged for having its
a coil arrangedthereon for energizationby an
tracted by said magnet body upon energization
of said coil, a reciprocating compressor member
to the cover 'I6 by means of a screw 2h which connected to said amature and forming there
ensures the requisite initial tension of the disk. with a freely oscillating unit, and resilient restor
The pressure valve 2I takes the form of an annu 'ing means connected to said unit so as to resist
lar diaphragm provided with apertures 22 which its deviation from a given position and tuned
are disposed in olf-set relation to corresponding to a natural frequency which causes the oscilla
tion of the‘unit to be substantially in resonance
apertures 23 in the cover IIì..v
The cover I6 of the compressor is so shaped with the periodic force of attraction of the elec
that, when the suction valve disk I8 is inserted tromagnet, said resilient means comprising a
Given. such designing of the working
chamber, it becomes possible, by suitable tuning
of the inherent frequency of the vibrating sys
tem to the frequency oi’ the magnetic force and
effective' number of turns reduced and, accord 70
“ingly the coemclent of resilience increased when
the load acting upon the spring is increased.
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