US 2588192 A
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Description (OCR text may contain errors)
March 4, 1952 J, D. AKERMAN ET AL 2,588,192
ARTIFICIAL RESPIRATION APPARATUS Filed Feb. 1, 1947 2 SHEETS -SHEET l March 4, 1952 J. D. AKERMAN ET AL 2,588,192
ARTIFICIAL RESP IRATION APPARATUS Filed Feb. 1, 1947 2 SHEETS-SHEET 2 AZIWEVEYS Patented Mar. 4, 1952 ARTIFICIAL RESPIRATION APPARATUS John D. Akerman and Vernon G. Townsend, Minneapolis, Minn; said Townsend assignor to said Akerman Application February 1, 1947, Serial No. 725,796
This invention relates to artificial respiration apparatus.
It is an object of the invention to provide an efiicient artificial respirator which can be used for any type of artificial respiration and which is particularly adaptable for use in place or" the so-called "iron lung with a resultant greater freedom of the patient being treated and greater accessibility to the patient by those taking care of him.
Another object of the invention is to provide artificial respiration apparatus which includes means for supplying or relieving pressure either negative or positive wherein the periods of pressure application and release can be varied simultaneously or independently and wherein the cycle period of application and/or release of pressure does not begin until the cycle period of the other is completed.
A further object of the invention is to provide artificial respiration of the type described above which can be made into a readily portable unit so that it can be relatively easily transported and set up and wherein the patient is provided with considerable freedom of movement.
The above and other obiects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same parts throughout the views, and, in which:
Figure 1 is a more or less diagrammatic view of an embodiment of the invention;
Figure 2 is a rear perspective view of the respirator element or vest;
Figure 3 is a horizontal sectional view through the vest;
Figure 4 is an enlarged fragmentary sectional view through a portion of the respirator vest showing a pressure line connection;
Figure 5 is a diagrammatic lay-out of the pressure control system; and
Figure 6 is a diagrammatic view of the control operating mechanism.
In Figures 1 through 3 there is shown a vest indicated generally at 6. The vest has a back portion H which preferably is of an open mesh or net-like fabric or other suitable material which afifords relatively free ventilation. The front of the vest comprises a double walled chamber 8 made up of spaced fluid tight fabric layers 9 and I0, said layers being flexible to provide comfort and also to permit expansion and contraction of the fluid chamber I I which is defined by the fluid tight layers 9 and It]. At one side of the vest is a hookless fastener slide element 12 which is adapted to separably connect a primary gripper portion 3 with either of a pair of parallel spaced gripper portions [4 01 I5. It is obvious that when the primary gripper portion I3 is connected with the secondary gripper portion I5 the vest can be made considerably smaller in girth.
At the other side of the vest is a series of buckle and strap units it which are also used to adjust the vest properly to the particular patient. Shoulder take-up straps I! and I8 are also shown. A pair of crotch straps 19 extend below the bottom edge of the vest and are connected between the front and rear portions thereof.
On the right hand shoulder portion of the vest 6 is a fluid conduit connector 20 which in the detail in Figure 4 is shown extending through the outer fluid tight layer 9. The conduit connection 26 is provided with an inner flange 2! and an outer flange 22 between which the outer fabric layer 9 is clamped. Adjacent the front center portion of the vest is a similar fluid conduit connection 123 which has a pressure gauge 24 connected thereto. A maximum pressure release valve 25 is shown in Figure 1 connected between the pressure gauge 24 and the pressure conduit connection 25.
In Figure 1 there is shown a fluid pressure source 26 which may be designed for creating pressures greater or less than atmospheric pressures, either a negative or a positive pressure is used depending upon the nature of the case and sometimes merely upon the preference of the doctor in charge of the case. A pressure supply conduit 21 is connected to the pressure source 26, this being termed a supply conduit whether there is a negative or a positive pressure created in the pressure source 26. There is a bypass 28 in the supply conduit 2'! whose flow capacity can be regulated by means of a valve 29 operated by a suitable external handle 36. The
pressure supply conduit 21 has a pressure supply cut-off valve 3| therein, and the conduit 21 also connects with one branch of a Y connection 32 which has a conduit 33 connecting it to the vest conduit 2% on the right hand shoulder portion of said vest. 34 to which is connected a conduit 35 which con stitutes a pressure release or outlet conduit having a cut-off valve 36 therein; In the arm'34 of the Y connection is an adjustable outlet pres sure valve 31 which may be constructed similarly There is a Y connection arm to the valve assembly 29, in the pressure supply line 21.
The pressure supply cut-off valve 3| and the outlet or release cut-off valve 36 are each provided with operating means in the form of solenoids 38 and 39, the details of the valves and their solenoid operators not being shown. This valve is closed by the weight of its movable plug and is opened by energization of the solenoid. The solenoids 38 and 39 are connected to a control unit indicated generally at 40 in Figure 1. Wires 4| connect the inlet or supply solenoid 38 with the control, and the wires 42 connect the outlet or release solenoid 39 with said control unit.
In Figure 5 there is shown a diagrammatic lay-out of the valve control system for alternately actuating and selectively determining the phase period of each valve in the cycle of operation of the pulsator. The control system is in the form of an electronic electric vibrator or relaxation oscillator.
In the circuit of Figure 5 there is shown an electronic tube 43 and a second electronic tube 44. The grid of the tube 43 is shown connected through a condenser 43a and a relay 45 to the plate of the tube 44, and the grid of tube 44 is connected through a condenser 44a and a relay 46 to the plate of tube 43. A potentiometer 41 is connected to the grid of tube 43 and its slide 41a is grounded, and similarly a potentiometer 48 is connected to the grid of tube 44 and its slide 4811 is grounded. The filaments of the two tubes are connected to a transformer 49 connected with a suitable current source not shown by means of conductors 50.
The relays 45 and 46 lie in the two above mentioned grid to plate connections respectively and operating current is supplied to them by conductors 5| which lead through resistances 52 and a conductor 53 to the filament circuit 54 of a rectifier tube 55.
The above circuit is based upon the oscillation characteristics of vacuum tubes. When the circuit is energized a voltage is built up for instance in the grid of the tube 43 which will also build up the plate current of said tube 43 until a maximum degree of current is reached, whereupon there is a drop off and an alternative build up of current in the grid of the tube 44 with a resultant build up of current in the plate 43. When the current is built up to a suflicient predetermined degree in the plate of the tube 43 and its circuit to the solenoid valve 3 I, the current flow through the tube 43 will drop, relay 46 will open and the solenoid valve 3| will release. When the current drops in the plate circuit of tube 43 it will build up in the plate circuit of tube 44, energizing the relay 45 and actuating the solenoid valve 36 oppositely to the movement of the valve 3|. By reason of the oscillation and circuit alternation of the tube circuits, the alternating valve action will be repeated continuously. This fluctuation will continue with the time interval constant if the input current and resistance are constant. However, the interval of building up of plate current in the tube 44 can be controlled by varying the resistance of potentiometer 41 and the interval of phase of the cycle of operation of the plate of tube 43 can be varied by adjusting the potentiometer 48.
With the alternate building up and relaxation of the two plate circuits the relays 45 and 46 will be alternately opened and closed. It will be seen that since the current to the plate of one tube does not begin to flow until relaxation of the flow of current to the other plate has taken place, one relay will not close until the other has opened and that such closure will take place immediately after the other relay has opened. Consequently, the phase period of operation of one relay can be varied by adjusting its potentiometer without afiecting the period of closure of the other relay while they will still alternate in their operation. This relay operation is, of course, transmitted to the solenoid valve indicated at 3| and 36 in the diagram in Figure 5.
In Figure 6 there is shown simple and efficient means for actuating the potentiometers 41 and 48. Figure 6 which is a diagrammatic view shows the potentiometers 41 and 48 actuated by knobs 56 and 51 respectively, said knobs being mounted upon operating shafts 59 and 60 respectively. The operating shaft 59 is provided with a pulley 6| which is connected by means of a belt or wire 62 to a pulley 63 mounted for rotation on an intermediate shaft 64. The right hand potentiometer shaft 60 is provided with a pulley 65 connected by a belt 66 to a pulley 61 rotatable on the shaft 64. The pulleys 63 and B1 on the shaft 64 have cooperating opposed friction surfaces-68. Also mounted on the shaft 64 is a collar 69 having a friction surface 10 cooperating with a friction surface 1| on'one side of the idler pulley 63. The shaft 64 can be moved longitudinally slightly to free the friction grip between the several friction surfaces on the pulleys 63 and 61 and the collar 69. In this condition the potentiometers 41 and 48 can be actuated independently of each other. However, when the shaft 64 is moved longitudinally to place the several friction surfaces together the shaft 64 can then be turned and the potentiometers 41 and 48 will be moved simultaneously. This permits a proportionate increase or decrease in the settings of the two potentiometers and also in the phase periods of actuations in the relays 45 and 46 and the solenoid actuated valves 3| and 36.
From the foregoing description it will be seen that we have provided artificial respiration appratus which is relatively compact and portable and which can be used upon a patient for continuous operation with any desired periods of inhalation and exhalation. The respiratory vest is relatively light and unconfining to body and limb movement of the patient and even permits the patient to move from place to place within the limits provided by the length of the conduits connecting the vest with the valve units and pressure source. The vest is readily adjustable for people of different sizes, and this fact plus the extreme flexibility of control periods for the application and release of pressure a single unit can be made adaptable for children as well as adults.
It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts 'without departing from the scope of our invention.
What we claim is:
1. An operating and control apparatus for a respirator of the type surrounding the chest and abdomen of the user, said apparatus having media for supplying fluid under pressure and for discharging fluid from a respirator, an electro magnetically operated supply valve interposed in said media and a second electro magnetically operated outlet valve interposed in said media, an electrically operated control system for operating said valves in opposite directions substantially simultaneously in a predetermined cycle, ,said control system comprising a vacuum tube "circuit including two relay circuits, each connected to control operation of the associated valve, said vacuum tube circuit including components interconnected with said relay circuits to alternately produce flow of current in said relay circuits first to one and then in the other in a controlled, predetermined manner. A.
2. The structure in combination set forth in claim 1 and certain of said components being related with said vacuum tube circuit to alternately and variably control the flow of current through the respective relays of said two relay circuits.
3. An operating and control apparatus for a respirator of the type surrounding the chest and abdomen of the user, said apparatus having media for supplying fluid under pressure and for discharging fluid from a respirator, an elctro-magnetically operated supply valve interposed in said media and a second electro ma netically operated outlet valve interposed in said and related with said relay circuits to alternately energize the relays of said two relay circuits in a predetermined cycle.
. JOHN D. AKERMAN.
VERNON G. TOWNSEND.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,595,755 Brooks Aug. 10, 1926 2,223,570 McMillin Dec. 3, 1940 2,288,436 Cahan June 30, 1942