US2311935A

US2311935A - Electrophysiotherapeutical apparatus

Info

Publication number: US2311935A
Application number: US261489A
Authority: US
Inventors: Joseph H Dobert
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-03-13
Filing date: 1939-03-13
Publication date: 1943-02-23
Anticipated expiration: 1960-02-23

Description

am nl Feb. 23, 1943. .-1. H. DoBEzR-r ELECTRO-PHYSIOTHERAPEUTICAL APPARATUS r'iled- March 15, 1939 WWNV Patented Feb.v 2.3, 1943 ELECTROPHYSIOTHERAPEUTICAL APPARATUS Joseph H. Dabert, Millvale, Pa.

Application March 13, 1939, Serial No. 261,489

(Cl. 12S-422) 22 Claims.

The present invention relates to electro-physiotherapeutical apparatus, and has for its primary objectl the provision of a new and improved apparatus for supplying various modalities of electro-physiotherapy to patients.

The present invention is an improvement over the apparatus disclosed and claimed in my copending application Serial No, 99,543, led September 5, 1936, upon Electro-physiotherapeutical apparatus, now Patent No. 2,182,233 granted December 5, 1939.

One of the primary objects of the present invention is to provide a new and improved apparatus of the type described that issimple to build as compared to other apparatus utilized for the same purpose and reliable in operation.

Another object of the present invention is the provision of a new and improved apparatus of the type described, so constructed and arranged that the operator may, by simple manipulation of a single control, obtain galvanic and sinusoidal current, various modifications of either of these two current forms, and various combinations thereof for use in electro-therapy.

A further and more specific object of the invention is to provide a new and improved apparatus of the type described employing thermionic devices adapted preferably, but not necessarily, to be energized from a single source of power, and selector switches for selectively controlling the connections of the thermionic devices to each other and to other electrical apparatus, wherein the number of thermionic devices and selector switches are reduced to a minimum and are so constructed and arranged with respect to each other as to produce reliable operation.

Another object of the present invention is to provide a new and improved apparatus for producing a wavy modality, i. e., one that fluctuates at a relatively low frequency from a predetermined value to predetermined values, either higher or lower, or both, than said one predetermined value. f

Another object of the invention is to provide-an apparatus of the type described in the preceding paragraph capable of providing a rest period between successive waves, during which rest period the current remains at its minimum value, and also an apparatus in which the rest period may be varied.

Another and more specific object of the present invention is to provide an apparatus of the type specied in the preceding paragraph comprising a patients circuit having therein current modifying means controlled by an independent timing circuit.

A further object of the present invention is to providea simpliiied apparatus of the typeL described having an improved circuit arrangement for transforming the wave modalities of current into sinusoidal wave modalities.

Other objects and advantages of the present invention will become apparent from the ensuing description, in the course of which' reference is had to the accompanying drawing in which:

Fig. 1 is a perspective view of an electro-physiotherapeutical apparatus embodying the features of the invention;

Fig. 2 is a schematic wiring diagram of the apparatus shown in Fig. 1; and

Fig. 3 is a chart listing the various modalities obtainable with the apparatus illustrated in the preceding figures and showing also the positions of the various switch blades comprising the selector means.

The multi-wave electro-physiotherapeutical apparatus of the present invention may be housed within a suitable cabinet I0 and provided with power, preferably from a sixty cycle alternating current source, through a single plug connector I2. The front pane1 I4 of the cabinet constitutes a control panel, upon which are mounted the various selector and control devices hereinafter described. In addition the control pane1 is provided with a pair of sockets I6 and I8 constituting output or patients terminals adapted to receive suitable applicators (not shown) The supply of power to the apparatus is controlled by a power switch 20 operable from an off to an "on position to energize the equipment. The connection of equipment to the power supply is indicated by a pilot light 22 energized simultaneously with the equipment.

The selection of the desired current modality is effected through a manually operable multi-element selector means indicated generally by reference character 24. In the embodiment of the invention herein described and illustrated, the selector means comprises four rotatable switch blades (to be described in detail hereinafter), all simultaneously operable to make the circuit changes necessary to produce the desired current modality. The small number of switch blades comprising the selector means forms one of the important features of the present invention.

The frequency of the wavy modality currents is controlled by a controller indicated generally by the reference character 26, and the frequency and polarity of the currents, as well as the magnitude thereof flowing in the patients circuit, may be observed by a meter 28 of the multiscale type. The connection of the meter inthe patients circuit and the selection of the desired scale is controlled by a switch 88.

The magnitude of the current supplied to the patients terminals is controlled first-by a potentiometer 82, and second by a switch 84 adapted to control the connection of a hereinafter to be described resistance in circuit with the patients terminals. The length of the rest period between successive waves of the wavy modalities is controlled by a control means 8.5 which, as will be describedy more fully hereinafter, makes adjustable contact with a resistance.

The selector means comprises a plurality of switches indicated generally by the reference characters I to 4, inclusive, and illustrated schematically in Fig. 2. 'I'he switches may be o1' any well known type and comprise what is generally called a gang switch. A switch of this type generally includes a4 number of. rotary switch blades equal to the number of switches,

and a number of contacts equal to the number of positions to which the switch is operable. Such'switches arewell known in the art and further detailed description or illustration thereof is deemed unnecessary. The rotary switch blades of switches I to 4 are indicated by reference characters 5 to 8, inclusive.

The apparatus of the present invention is adapted to produce ten modalities of current, and consequently the selector means 24 is operable into ten different positions A to J, inclusive, as shown in Fig.,3. In each position the switch blades engage contacts so connected in various circuits that the selection of the desired modality and the supply thereof to the patients terminals is controlled by a single selector means.

pusating direct. and oscillating currents, andV these are translated into wave and sinusoidal wave modalities by means including thermionic devices and switches.

Referring now to the schematic wiring diagram illustrated in Fig. 2, it may be seen that the alternating current is supplied through the plug connector I2 and power control switch 20 to a pair of

transformers

48 and 42 having primary windings 44 and 45, respectively. Current is supplied t0 the patients terminals I6 and I8, through a patients circuit includingthe transformer 48, and the frequency of the wave modality currents is controlled by an independent timing circuit energized through-the transformer 42.

Transformer 48 is provided with four low voltage

secondary windings

48,58, 52 and 54 for supplying heating current to the illaments of the thermionic vacuum tubes V-I, V--2, V--3 and V-4, respectively. Transformer 42 is provided with a single low voltage secondary winding 58 for supplying heating current to the filanient of the thermionic vacuum tube V-5. The

transformers 40 'and 42 include secondary windings 58 and 60 providing a source of high potential for the anode circuits of vacuum tubes V-I and V-5, which function as full-wave rectiflers.

Rectiiler ytube V--I supplies pulsating direct current to

conductors

62 and 84 connected, respectively, to the mid-point of the anode transformer winding 58 and tothe filament of the tube. The current then passes through a illter, comprising a chokek 88 in series with conductor 64 and a condenser 88 connected across the

conductors

52 and 84, which serves to smooth the pulsations so that a galvanic current is supplied to the terminals of a high resistance voltage dlvider resistor l0.

Assuming for the time being that the selector means 24 has been operated to condition the apparatus for supplying. galvanic` current to the patients terminals, then the switches I to 4, inclusive,` occupy the positions in which they are shown in-Fig`. 2.' Asi-a result galvanic current is supplied, when the apparatus is energized, to the patients terminals, through a circuit including the conductor 82, a conductor 'I2,=a relathe potentiometer contact 82, through all or a portion of a relatively low resistance 84, or directly, dependent upon the position of the movable switch blade 88 of switch 84, conductor 88, switchvblade 90 of a `relay operated reversing switch 92, the function and construction oi which will be described fullyshortl'y, and conductor 94. The lower terminal of potentiometer resistor 82 is connected to patients terminal II through the conductors 88, 98, a second switch blade 98 of the reversing switch 82, conductor |08 and either directly to the terminal I8 through switch 88 (as indicated) or to the terminal through the meter 28.

Pulsatlng direct current is supplied tof the potentiometer resistor 82 and thence to the patients terminals through a circuit identical with thatdescrlbed above, except for the fact that the filter is by-passed and the pulsating direct current from the rectiiler is conducted directly to switch No. I by a conductor |02 with which the switch blade 5 isin contact when this modality is selected (see the switch positions for modality D);

Alternating current of the same frequency as the power source is supplied to the potentiometer resistor 82 and the patients terminals through a circuit that is` substantially the same as the two described above, except for the fact that both the rectifier and illter are by-passed by a conductor |04 with which the switch blade 5 is in contact when this modality is selected switch positions for modality J) The last described connections result in the connection -of the potentiometer resistor 82 to the lower half ot the secondary winding 58 of the transformer 48. Whenthe alternating current modality is selected, the whole of resistv(see the the terminals of the potentiometer resistor 82 and thence to the patients terminals. Tube V,-2 has associated therewith a transformer |88 adapted to couple the output and input circuits of the tube in a well known manner. One winding |08 of the transformer is connected across conductor 84 and the anode of the tube. The other winding III of the transformer is connected to the grid and by conductor ||2 to one terminal of a tuning condenser ||4, the other terminal of which is connected to conductor 82. A branch conductor ||8 connects the conductor ||2 to the voltage divider 10. The filament of the tube is connected by conductor ||8 to the voltage divider. The oscillatory current furnished by the oscillator is supplied to the lower terminal of potentiometer resistor 82 through conductors 82, 12, a portion of resistance 14, movable contact 18, conductor 18, switch blade 8 in contact with the latter, and conductor 80. It is supplied to the upper terminal of the resistor by conductor |22 and the switch blade 5, which is in contact therewith (see switch positions for modality G).

In the production of the various wave modalities (not the sinusoidal wave) the galvanic, pulsating direct and oscillatory currents are modified so that they gradually increase from a predetermined minimum value to a vpredetermined maximum value, and then decrease to the minimum value at substantially fixed relatively long time intervals. The modification is effected by the vacuum tube V-3, which is then connected in series with the potentiometer resistor 82 through conductor |23 connected to the anode of the tube and adapted to be connected to one terminai or resistor sz by switch made s of switch No. 2. The potential of the grid |24 of the tube is varied periodically and gradually to produce a similar change in the plate current of that tube, which current flows through the potentiometer resistor.

The desired variation in the potential of the grid of tube V-3 is obtained by connecting it -by a conductor |28 to the previously mentioned movable contact 35 associated with resistance |28 forming part of the previously mentioned independent timing circuit. The potential applied to the grid |24 at any particular time is dependent upon the value of the current flowing through resistance |28 having a value intermediate the low and high resistance values mentioned above. 'I'he flow of current through the resistance |28 is gradually varied from a minimum to a maximum and then back to a minimum valueA by timing means including the vacuum tube V-4, amarginal relay |30 connected to the anode of the tube and to one terminal of the resistance |28, and a condenser |32 connected across the grid and filament of the tube and adapted alternately to -be charged and discharged through a circuit including a selected one of a plurality of resistances |38. The resistances |38 each have adifferent value and they, together with the condenser I32, form part of the frequency control means 28. 'I'he `alternate charging and discharging is controlled by a pair of switch blades |38 and |40 operated by the relay |30.

Before proceeding further with the details of the circuit connections of the elements Just enumerated, it may be well to describe briefly the manner in which they are supplied with energy from the transformer 42.

'I'he transformer secondary windings 58 and 8l are connected-in-accordance with usual practice to the filament and anodes of' the rectifier tube V-5, and the pulsating direct current output thereof is smoothed by a filter comprising the choke coil |42 and a pair of condensers |44 connected in parallel across the conductors |48 and |48. The conductor 48 is the positive conductor and the conductor 48 negative. 'I'he positive conductor |48 is tied to the negative conductor 82 of the patients circuit by a conductor |50. The output from the filter is supplied across the terminals of a voltage divider |82 having an intermediate value of resistance. The filament of the vacuum tube V-4 is connected by conductor |54 to a point on the voltage divider |52 having a potential more positive than the potential of the conductor |48, and the anode of the tube is connected to a point more positive than the one to which the conductor |54 is connected, and more positive than conductor 82, by a conductor |58 leading to the voltage divider 10. The conductor |58 isadapted to be connected to the anode of the tube through switch No. 4 and solenoid |30. The switch blade 8 of switch No.

4 is operable from an ofi. position in which it is indicated into two positions to connect the anode to the voltage divider. In one position the connection is through the whole of resistance |28. This connection is through conductor |58. In

vthe other position the connection is through a part of resistance |28 and the connection is made through conductor |80.

When the relay |30 is de-energized, as it is when the apparatus is disconnected from the power source, the switch blades |38 and |40 occupy the positions indicated wherein the resistance-condenser circuit and grid of tube V-4 are connected to conductor |54 so that the grid is at a potential that is more positive than if connected to conductor |48 through switch blade |40 and branch conductor |82. In the position indicated, the condenser |32 is adapted to discharge through th resistances |34 and |38 and the grid rendered most positive through conductor |54, switch blade |38 and conductor |84. Consequently, when the apparatus is energized the tube V-4 is in its most conductive condition because of the more positive potential applied to its grid, and the relay |30 is designed to be energized at this time.

Upon the energization of the relay |30, the switch blade |38 is moved upwardly to disconnect the resistance-condenser circuit and grid from the more positive conductor |54, and the switch blade |40 is adapted to be moved upwardly to connect the resistor-condenser circuit and grid to the more negative conductor |48 through the conductors |82 and |64. As a result of this lastmentioned operation the grid potential is gradually made more negative at a rate dependent upon the proportions of the resistance 38, and the condenser |32, in a manner well known to those skilled in the art. The gradual application of a more negative potential to the grid decreases the plate current flowing through the tube V-4 to a minimum value at which the relay |30 is deenergized, and the switch blades |38 and 40 return to the positions indicated, and the condenser |32 gradually discharges into the resistances and the grid again made more positive. The relay |30 is, as has been mentioned above, a marginal relay, that is, it is adapted to be energized when a current of predetermined value flows therethrough and remains energized until the current decreases to a value below the aforesaid predetermined value.

The flow of current through the resistance |28 thusA varies from a predetermined maximum to a predetermined. minimum value at recurring periods, dependent upon the setting of the frequency control means 28. When the current flowing through the resistance |28 is at a maximum, the voltage drop across the portion of resistance |28 included between the conductor |88 and the switch blade 8 is a maximum, and consequently the grid is most negative with respect to the filament which is `connected directly to conductor 82. When the current flowing through the resistance is a minimum, that is, when the relay |88 is deenergized, the voltage drop is least and the grid potential is more positive. It is desirable that the negative potential applied to the grid of tube lV--8 be made substantially zero in order to obtain a desirable maximum value for the wavy modality currents, and it is for this rea,- son that the conductor |56 is connected to a point on the voltage divider 18 having a potential above that of conductor 82. The effector connecting the conductor |58, as indicated, is the application of a `potential bucking the negative potential in resistance |28 resulting from the flow of current therethrough.

Since the vacuum tube V--8 is interposed in series with the potentiometer resistor 82 and the latter is adapted selectively to be connected to the sources of galvanic, pulsating direct and oscillatory currents, it maybe seen that the latter current modalities can readily be modified to produce the galvanic, pulsating direct and oscillatory wave modalities, and that the frequency of the waves may be controlled as desired by the frequency control means 26.

A rest period may be interposed between the successive waves by adjusting the movable contact connecting the grid |24 of tube V-3 to the resistance |28, so that the tube is biased to cut-ofi' before the current flow through relay |80 reaches its maximum value. If this be done, no current flows through the potentiometer resistor during the time that the tube is biased to cut-off.

The wave modalities above described are transformed into sinusoidal wave modalities by reversing the connections of the terminals of the potentiometer resistor 82 with respect to the patients terminals I6 and |8. This reversing operation is effected by the previously mentioned reversing switch` 82.

In order to prolongthe life of the reversing switch, the reversals effected thereby should take place when the current flowing to the patients terminals is at a minimum (this minimum value is ordinarily zero because the maximum negative potential applied to the grid of the tube V-8 is sufllcient to bias it to its cut-off point) Therefore, it is necessary that the reversing switch be tied in with the operation of the timing circuit, and this is accomplished by placing the reversing switch operating relay |10, which is of the marginal type, under the control of the relay 'I'he relay |18 and its associated circuits are. therefore, rendered operative when the sinusoidal wave modalities are selected. When` these are selected, switch No. 3 is operated from the position in which it is shown to connect relay |10 across conductors B2 and 84, through conductor |12 and through conductor |14,'resistance |18, conductor |11, switch blade 1 of switch No. 8 and conductor |18, respectively.

The relay |10,.being as heretofore mentioned a marginal relay, is adapted to be energized when the current owing therethrough reaches ya predetermined value, andv remains energized until the current decreases below a value less than the predetermined value. The resistance |18 in series therewith is so proportioned that the cur? rent flowing through the` relay and resistance is insufncient initially to energize the relay,but is sufiicient to maintain the relay energized when the latter is once energized. It may be seen, therefore, that according to the present inven-4 tion the relay must be provided with additional current for its energization, and that the normal current fiow therethrough must be decreased in order to de-energize the relay.

The increase and decreasein thenormal current flow through the `relay |10 is obtained by Va condenser which is selectively positively and negatively charged with respect to the direction of flow of current through the relay, thereby to add to or subtract from the normal current flowing through the relay by amounts suillcient, respectively, to effect energization and de-energization ofthe relay. The condenser which is so charged is indicated by the reference numeral |80, one terminal of which is connected by conductor |82 to the conductor. 82, and the other terminal of which is connected by conductor |84 to a resistance |88. The latter is connectedby a conductor |88 to switch blades |80 and |82 adapted to be raised upwardly from thepositions shown in Fig. 2 whenever the relay |88 is energized. y

When the switch blades are in the positions indicated, the condenser is adapted to be charged positively through a. circuitincluding the switch |80, a conductor |84 leading therefrom to a pair blade 1 of switch No. 8, and conductor |18 lead-V ing to conductor 84. Y When the switch blade 1 is in circuit making position andthe equipment;4 energized, the terminal of the condenser connected to conductor |84is charged positively.

When the relay is energized, the charge from the condenser is impressed across the relay` |10 in a direction such as to increase the flow of current therethrough to a value sufficient to energize the relay. The charge is impressed` through a circuit including switch blade |82, now in engagement with a conductor 282 connected by conductor |14 to the relay |18. The energizaf` tion of relay |10 effects a reversal of the connections of the potentiometer resistorterminals to the patients terminals by operation of the switch blades 80and 88 from their lowermost to their uppermost positions. The relay |10 once energized remains energized even after the condenser charge is dissipated and the relay |80 de-energized. However, the lcircuit arrangement is such that upon re-energization of the relay |30, the relay |10 is de-energized by impressing the charge from condenser |80 thereon, the condenser at this time having a charge that is negative with respect to the direction of flow of current in the relay. The condenser` |80 is provided with a negative charge in the following manner:

Reviewing the operation of the energization and de-energization of relay |10, it may -be seen that it is alternately energized and de-energized each time that the relay |30 is energized.

Before reviewing the operation of the apparatus, it should be noted that the magnitude of the current supplied to the patients terminals may be controlled not only by the potentiometer 32, but also by the switch 34, the switch blade 86 of which is adapted to be operated from the position shown in which the whole of resistance 84 is in the patients circuit into engagement with conductor 208 to decrease the amount of the resistance in the circuit or into engagement with a conductor 2|0 to cut the resistance out of circuit entirely.

The meter 28 may be inserted in the patients circuit, if desired, by operating the switch 30 from the position in which it is shown into engagement with either of conductors 2|2, 2|4. When operated into engagement with the former, the low reading scale of the meter is rendered effective, and when operated into engagement with the latter the high reading scale of the meter is rendered effective. A low capacity blocking condenser 2|6 is connected directly across the patients terminals I8 and I8.

It is believed that while the operation of the apparatus in its entirety is fairly comprehensible from the above detailed description, a brief review of the operation of the system in the production of the various modalities of current will serve a useful purpose. The various modalities will, therefore, be considered ir. the order in which they are alphabetically listed in Fig. 3.

(A) Galvamc In the description of the operation of the apparatus for the production of this modality as well as the other modalities, it is assumed that 'the plug connector l2 is connected to a sixty cycle alternating current source,` switch 20 is closed to energize the transformers, and

control devices

26, 30, 32, 34 and 35 are inthe positions indicated. 'I'he pilot light 22 is energized to give an indication that power is being supplied to the apparatus. The selector switch 24 is operated into position A, conditioning the apparatus for the supply of galvanic current to the patients terminals. In position A switch No. establishes a circuit from conductor 84 to the potentiometer resistor 82, and switch No. 2 establishes a circuit from conductor 62 to the other end of wthe potentiometer resistor 82 through conductor 12, a portion of resistance 14, movable contact 16 and conductors 18 and 80. Switches Nos. 3 and 4 are in their off position at this time so that the time control and reversing means are inoperative. As previously explained, the

conductors

62 and 84 are connected to the terminals of the voltage divider resistor which is supplied with a galvanic current from the rectier in a manner that need not be described again. The galvanic current is supplied from the potentiometer resistor 82 to the patients terminals through

switch blades

80 and 98 of the reversing switch 82. which are maintained in the position indicated by reason of the fact that the relay is inoperative. The amount of current flowing in the patients circuit may be determined by observation of meter 28 which may be included in the circuit by operation of switch 30 into contact with conductors be obtained by adjustment of the movable con- The magnitude of the current flowing in the patients circuit may be controlled in the first instance by switch 34, which may be operated from its oi position into contact with conductors 208 or 2|0, thereby increasing the current from a minimum to an intermediate or to a high value.

Close adjustment of the current is had by means of the potentiometer movable contact 32, and a further adjustment of the current may tact 16, but ordinarily it is not necessary to resort to this and, therefore, the contact is ordinarily placed within the cabinet |0 where it is relatively inaccessible. The use of the meter and the adjustment of the current to low, intermediate and high values by switch 34-is lthe same for all modalities and the operation thereof will not be described again.

(B) Galvanic wave When this modality is selected, switch No. remains in engagement with conductor 84, switch No. 2is operated so that switch blade 6 engages conductor |23, thereby placing the current modifying tube V-3 in circuit, switch No. 4 is brought linto contact with conductor |60, thereby rendering effective the time control means controlling the potential applied to grid |24, and switch No. 3 remains in its open position, thereby maintaining the reversing means inoperative.

The change in the position of switch No. 2 merely cuts out the resistance 14 and places the vacuum tube V-3 in place thereof so that the lament of the latter is connected to conductor 62 and the anode to conductor 84 through conductor |23, switch blade 6, conductor and switch blade 5. l

Relay |30 having been de-,energized, the potential applied to the grid of the timecontrol tube V-4 is most positive because the grid is connected to conductor |54 through switch blade |38, conductor |64 and the selected resistance |36. Consequently, the tube is in its most conductive condition and the relay |30 is immediately energized connecting the resistorcondenser circuit to the most negative conductor |48 lthrough conductor |62, switch blade |40, and conductor |64. A negative charge is built up in the condenser |32 at a rate dependent upon the value of the selected resistance |36, and the potential of the grid consequently becomes more negative gradually at a rate dependent upon the proportions of the resistance and condenser. After the grid potential reaches a certain negative value, the current flowing in the output circuit of the tube decreases to a point Where the relay 30 becomes de-energized and the switch blades |38 and |40 are returned to the positions indicated, wherein the condenser-resistance circuit is connected to the more positive conductor |54, again to make the grid more positive and in time to increase the current in the anode circuit thereof to a value suiiicient to energize the relay. It may be seen, therefore, that the current flowing through the resistance |28. varies from a maximum to a minimum value periodically. The potential of the point to which the movable contact 35 is attached, therefore, varies, being most negative when the vcurrent. is at a maximum. and least negative when the current is at a minimum. The resistances are so proportioned that the variation is great enough to make the grid, |24 of tube V-3 sulciently negative to bias the tube to cut-oi! so that the current flowing through the potentiometer resistor 32 is reduced to zero. `I'f desired the contact 35 may be so adjusted that the point of cut-off is reached before the current flow in resistance |28 reaches its maximum value so as to provid rest periods between the successive waves.

As stated above inthe detailed description of the circuit arrangeineni'`V the vconductor `|56 vist...

l v connected to'a point on voltage divider 10 sumcient to render the bias upon grid |24 of tube V-3 substantially zero, thereby to determine the most lconductive condition of the tube.

The frequency of the waves is controlled by the frequency controller 26, which is adapted to be (C) Slow sinusoidal The selector control means 24 is operated into position C and the switches remain in the positions described under the previous heading, with the exception of switch No. 3 which isadapted to complete a circuitacross conductors |11 and |10. thereby rendering effective the reversing switch 92. It is believed sufllcient to state at this point that the relay |10 yis energized for every alternate energization of relay |30, and Similarly de-energized upon the other alternate energizations of relay |30. The energization of the relay |10, it may be remembered, is effected by discharging condenser |80, `when positively charged, into the relay |10, and the de-energization of the relay is effected by discharging the condenser, when negatively charged, into the re-` lay. 'I'he alternate charging and discharging oi' the condenser positively and negatively is eected through switch blades |96 and |98 under the control of relay |10, and switch blade |90 under the control of relay |30. The discharge of the condenser into the relay is effected by switch blade |92 under the control of relay |30. The operation of the system, except forthe reversing switch, remains the same as in the previously described modality, and the reversing switch is effective merely to reverse the connections of the patients terminals I6 and |8 with respect to the potentiometer connection 32 kand the lower resistor terminal, which is connected to conductor 00. The reversals are effected as described above at a time when the current flowing in the patients terminals is at a minimum (ordinarily zero), because of the fact that the reversal is eil'ected whenever relay |30 is energized, that is, when maximum current ows through the resistance |28, at whichtime the bias applied to tube V-3 is most negative.

(D) pulsating direct When the apparatus is conditioned for the supply of pulsating direct current, the selector means 24 is operated into position D, at which time switch No. is connected to conductor |02, switch No. 2 to conductor 18. and switchesNos.

(E) Pulsatina direct wave When this modality is selected, switch No. remains connected to conductor |02, switch No. 2 is operated to connect the vacuum tube V-I in the patients circuit, switch No. 3 remains in its off position, and switch No. 4 renders effective the time control circuit. I'he Vpotential applied to the grid |24. of the tube V'3' is periodically` varied in the manner described in detail in connection with modality (B) a'd"the-pulsating direct current is transformed into a pulsatingdirect wave modality.

(F) Pulsating direct sinusoidal Whenthis modality isy selected, switches Nos. I, 2 and 4 remain connected in the manner last described and switch No. I isconnected to conductor |11, thereby to render effective the current reversing means. The operation of the system at this time is substantially the same as for modality (C) and the pulsating direct current supplied to the potentiometer resistor 02 and tube V--3 is transformed into soidal modality.

(G) oscillatory When the oscillatory modality is selected. switch No. is connected to the output of the oscillator tube V-2 by conductor |22, switch No. 2 is connected to conductor 18, and switches Nos. 3 and 4 are in their oil positions. The operation of the system at this time is the same' as when modalities (A) and (D) are selected, the only diierence being that oscillatory current is supplied to the potentiometer resistance instead of the galvanic or pulsating direct.

(H) Oscillatory wave (I) oscillatory sinusoidalv f When this modality is selected, switches Nos. I, 2 and 4 remain in the positions they occupy when the oscillatory wave modality is selected, and switch No. 3 is connected to conductor |11, thereby to renderveffective'the current reversing means. 'I'he operation of the apparatusat this "time corresponds to the operation when current modalities (C) `and (F) are selected, and consequently further description of the operation is not deemed necessary at this point.

'(J) Alternating When the alternating current modality is selected, the lower'half of transformer 50 is connected tothe` potentiometer resistor 02 through a previously described circuit that includes conductor |04 to which switch blade 5 of switch No.

a pulsating direct sinu- I is connected. Switch No. 2 connects in the circuit the whole of resistance 14. Switches Nos. 3 and 4 are in their o positions to render ineffective the wave frequency control and reversing means.

While a preferred embodiment of my invention has been described, many modifications may be made without departing from the spirit of the invention, and I do not wish to belimited to precise details of the construction set forth.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An electro-therapeutic apparatus, including in combination, output terminals, a source of current and means interconnecting said source and terminals for transforming said current into a wavy modality of electro-physiotherapy, said means including a circuit interconnecting said source and terminals, a single thermionic device having a plurality of electrodes, two of which are permanently connected in said circuit, and periodically acting means operating independently of said device for varying the potential applied to another of said electrodes.

2. An electro-therapeutic device, including in combination, output terminals, a source of current and means interconnecting said source and terminals for transforming said current into a wavy modality of electro-physiotherapy, said means including a circuit interconnecting said source and terminals, a single thermionic device having a cathode, anode, and another electrode,

said anode and cathode being permanently connected to said circuit, periodically acting means operating independently of said device for varying the potential applied to said other electrode and means for varying the period of operation of said last mentioned means.

3. An electro-therapeutic apparatus, including in combination, output terminals, a source of a1- ternating current, means co-operatively associated with said source for providing sub-sources of galvanic, pulsating direct, or oscillatory current modalities, and means interconnecting said source and terminals for transforming selected ones of said modalities into wavy modalities, said means including a circuit adapted to interconnect said source and terminals, a single thermionic device in said circuit and having a control electrode, and periodically operating means for varying the potential applied to said control electrode, and single manually operable control means for establishing circuit connections between the sub-v for transforming said current of a selected subsource into a wavy modality, said means including a circuit adapted to interconnect said selected sub-sources and terminals, a thermionic device having an anode and cathode in said circuit and another electrode, periodically acting means operating independently of said device for varying the potential applied to said other electrode, and single manually operable control means comprising a plurality of simultaneously operable switches for establishing circuit connections between the sub-sources of current and the transforming means for supplying the selected modality to the output terminals.

5. An electro-therapeutic apparatus, including in combination, output terminals, a source of current, means interconnecting said source and terminals for transforming said current into a wavy modality of electro-physiotherapy, said means including a circuit interconnecting said source and terminals, a thermionic device having a plurality of electrodes, at least two of which are connected to said circuit, a resistance, a connection from another of said electrodes to a predetermined point on said resistance, and means for supplying current to said resistance through another circuit and for periodically .varying the current flowing through` said resistance, and

thereby the potential of said point and the potential applied to said other electrode.

6. An electro-therapeutic apparatus, including` in combination, output terminals, a source of curleast one of which is connected to said circuit,

a resistance, a connection from the second of said electrodes to predetermined point on said resistance, and means for periodically varying the current flowing through said resistance and thereby the potential of said point and the potential applied to said electrode, the connection of said second electrode to said resistance being adjustable and the current flow being so regulated that the thermionic device is rendered substantially nonconductive before the current flow through said resistance is changed to vary the potential in a direction to render the device more conductive; thereby to provide adjustable rest periods between successive waves.

7. An electro-therapeutic apparatus, including in combination, output terminals, a source of current, and means interconnecting said source and terminals for transforming said current into a wavy modality of electro-physiotherapy, said means including a circuit interconnecting said source and terminals and a Wave frequency control means for controlling the conductivity thereof, said circuit including a thermionic device, and said frequency control means including a second thermionic device, and a periodically charged and discharged condenser for controlling the conductlvity of said device, said second mentionedv device controlling the action of the first mentioned one. i

8. An electro-therapeutic apparatus, including in combination, output terminals, a source`of current and means interconnecting said source and terminals for transforming said current into a wavy modality of electro-physiotherapy, said means including a circuit interconnecting said source and terminals and a wave frequency control means, said circuit including a thermionic device having an electrode for controlling the conductivity thereof, and said control means including a thermionic device having an anode and anl electrode controlling the conductivity thereof, means connected to the anode circuit of said device connected to the electrode of said first mentioned device and operative to vary the potential of said electrode responsive to the ow of current in said anode circuit, and means including a condenser connected to the electrode of said device, resistance means in circuit therewith, and a relay in said anode circuit responsive to the current flowing therethrough adapted alternately to charge or discharge said condenser through said resistance means.A

9. An electro-therapeutic apparatus, including in combination, output terminals, 'a source of alternating current, a ilrst transformer, means interconnecting said transformer and output terminals for transforming current derived from the transformer into a wavy modality of physiotherapy, said means including,r a circuit interconnecting said source and terminals, and a wave frequency control means, said' circuit including a thermionic device having an electrode for controlling the conductivity thereof andsaid control means including a thermionic device havving an anode, and an electrode controlling the conductivity thereof, a second transformer, and means energizing said second thermionic device from said second transformer, means connected tothe anode circuit of said second thermionic device for varying the potential of the electrode of said first-mentioned thermionic device responsive to the flow of current in `said anode circuit,

and means including a condenser connected tov l whereby said condensers are alternately charged and discharged through said resistance means and the potential of the electrode of said secondmentioned thermionic device gradually and periodically varied between predetermined maximum and minimum limits at a rate determined by the value of said resistance means.

10. An electro-therapeutic apparatus, including in combination, output terminals, a'source of current, means including a circuit interconnecting said source and terminals having therein a single thermionic device having a plurality of electrodes, at least one of which is included in said circuit, and periodically operating means for varying the potential applied to another of said electrodes for transforming said current into l a wavy modality of electro-physiotherapy, and

periodically operating current reversing means interposed between the output of said thermionic device and the output terminals.

11. An electro-therapeutic apparatus, including in combination, output terminals, a source of current, means including a circuit interconnecting said source and terminals havingtherein a single thermionic device having a plurality of electrodes, at least one oi which is included in said circuit, and periodically operating means for varying the potentialapplied to another of said electrodes for transforming said current into a wavy modality of electro-physiotherapy, and current reversing means interposed between said therminoic device and output terminals controlled by said periodically operating means.

12. An electro-therapeutic apparatus, including in combination, output terminals, a source of current, means including a circuit interconnecting said source and terminals having therein a single thermionic device having a plurality of electrodes, at least one of which is included in said circuit, and periodically operating means for varying the potential applied to another of said electrodes fortransforming said current into a wavy modality oi' electro-physiotherapy. and current reversing means including switch means and a relay controlled by said periodically oper]- f ating means interposed between said thermionic device and the output terminals.

13'. An electro-therapeutic apparatus, including incombination, output terminals, `a source of alternating current, and means connected to saidsource for transforming the current into sub-sources of galvanic, pulsating direct, and oscillatory modalities of electro-physiotherapy,

and means interposed between said sub-sources l and output terminals adapted selectively to be rendered effective to transi'ormsaid modalities into wavy modalities, and single selector means lmanually operable into av plurality ofpositions for supplying said output terminals with current directly .from said sub-sources or through said transforming means, said selector means comprising three switches, one adapted to con-` trol `the connection of the output terminals to the sub-sources, and a second and third to control the effectiveness of the means for transforming the selected` sub-source into a wavy modality. y

14. An electro-therapeutic apparatus, including incombination, output terminals, a source of alternating current, andv means connectedto said source for transforming the current into sub-sources of galvanic, pulsating direct, and

oscillatory modalities of electro-physiotherapy, and means interposed between said sub-sources and output terminals `adapted `selectively to be rendered effective totransform said modalities into wavy modalities, reversing means adapted` selectively to be connected between said lastmenticned means and the output terminals for transforming said wavy modalities into sinusoidal wavy modalities, and singleselector means manually operable into a plurality of positions for supplying said output terminals with .cur-- rent directly from said sub-sources, through said first-mentioned transforming means or through both said transforming and reversing means, said switch means comprising. four switches, one adapted to control the connection of the output terminals to the sub-sources, a

second and third to control the effectiveness of the. means for transforrnng the selected subsource into a wavy modality, and a fourth Ifor controlling the effectiveness of the reversing means. i 4 i 15. An electro-therapeutic apparatus, including in combination, output terminals, a source of galavanic current, means including circuit connections and a single thermionic device having an electrode the potential of which is adapted to be periodically varied i'or transforming the galvanic current into a galvanic wave modality, thermionic means for periodically varying the potentialiapplied to said electrode,

and a single manually operable selector means mally supplyingsaid relay-with current-insufllcient to operate but suilicient to maintain the same in operated position when it is once operated, and means operable selectively to increase or to decrease the current normally flowing through said relay for controlling the operation thereof, said last mentioned means including a condenser adapted periodically to be discharged through said relay and alternately to be charged in such manner that the discharge temporarily increases or decreases the ow of current through the relay, and a periodically operating relay for controlling the charging and discharging of said condenser.

17. An electro-therapeutic apparatus, including in combination, output terminals, a source of current, means including a circuit interconnecting said source and terminals having therein thermionic means of the type having an electrode the potential of which is adapted to be varied to control the conductivity thereof, periodically operating means for varying the potential applied to said electrode for transforming said current into a wavy modality of electro-physiotherapy, and current reversing means interposed between said thermionic means and the output terminals, said last-mentioned means including a rst relay controlling circuit connections to the output terminals, a second relay controlled by said periodically operating means, means normally supplying said first-mentioned relay with current insufficient to operate but sufiicient to maintain the same in operated position when it is once operated, and means controlled by said second-mentioned relay for periodically increasing or decreasing the current flowing through said first-mentioned relay sufciently to operate and return the same to non-operated position.

18. An electro-therapeutic apparatus, including in combination, output terminals, a source of current, means including a circuit interconnecting said source and terminals having therein thermionic means of the type having an electrode the potential of which is adapted to be varied to control the conductivity thereof, periodically operating means for varying the ptential applied to said electrode between predetermined limits for transforming said current into a wavy modality of electro-physiotherapy, one of said limits having a value such that the current is reduced to substantially zero, and current reversing means interposed between said thermionic means and the output terminals, said last-mentioned means including a rst relay controlling circuit connections to the output terminals, a second relay controlled by said periodically operating means adapted to be energized when said current is substantially zero, means normally supplying said rst mentioned relay with current insuflcient to operate but sufficient to maintain the same in operated position when it is once operated, a condenser. sources of positive and negative potential, and switch means conjointly controlled by said relays for alternately connecting said condenser to said sources and discharging said condenser through said ilrst relay, the discharge being effected upon each energization of said second relay, whereby the current reversals are effected when the current supplied to the output terminals is substantially zero.

19. An electro-therapeutic apparatus, including in combination, output terminals, a source of current and means interconnecting said source and terminals for transforming said current into a wavy modality 0f electro-physiotherapy, said means including a circuit interconnecting said source and terminals, a single thermionic device in said circuit having a control electrode, and means including a periodically operating thermionic tube operating independently of said device for varying the potential applied to said control electrode.

20. In combination, a relay, means including a direct current circuit for normally supplying said relay with current insufficient to operate but su'lcient to maintain the same in operated position when it is once operated, and means normally disconnected from the relay operable periodically and alternately to supply said relay with a current charge of one polarity to increase momentarily the current owing through said relay for operatingr it and to supply said relay with a current charge of an opposite polarity to decrease momentarily the current normally flowing through said relay for effecting return thereof to its non-operated position, whereby said relay is periodically operated between its operated and non-operated positions.

21. In combination, a relay, means including a direct current circuit for normally supplying said relay with current insuiicient to operate but sufficient to maintain said relay in operated position when it is once operated. and means operable selectively to supply said relay with an electric charge of one polarity for momentarily increasing the normal current flow through said relay for operating said relay to its operated position and with an electric charge of an opposite polarity for momentarily decreasing the normal current ilow through said relay for returning said relay from its operated position, said last mentioned-means including a second circuit normally disconnected from said first mentioned circuit.

22. In combination, a relay, means including a direct current circuit for normally supplying said relay with current insuflicient to operate but suiiicient to maintain said relay in its operated position when it is once operated, and means operable selectively to supply said relay with an electric charge of one polarity for momentarily increasing the normal current ow through said relay for operating said relay to its operated position and with an electric charge of an opposite polarity for momentarily decreasing the normal current flow through said relay for returning said relay from its operated to its non-operated position, said last mentioned means including a condenser normally disconnected from said relay, means for periodically connecting said condenser to said relay to effect discharge 0f the condenser therethrough, and means for providing said condenser with charges of opposite polarity each time it is disconnected from the relay, whereby the normal current ilow through the relay is alternately increased and decreased to effect operation of said relay between its operated position and non-operated position.

JOSEPH H. DOBERT.