US 3261358 A
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July 19, 1966 P. D. BERNARD 3,261,358
SOURCE OF CURRENT FOR APPLICATION TO A PATIENT FOR OBTAINING A THERAPEUTIC EFFECT 2 Sheets-Sheet 1 Filed Oct. 28, 1963 TO PATIENT BEING TREATED s ,4 TTOR/VEy July 19, 1966 P. D. BERNARD 3,261,358
SOURCE OF CURRENT FOR APPLICATION TO A PATIENT FOR OBTAINING A THERAPEUTIC EFFECT iled Oct. 28, 1963 2 Sheets-Sheet z OOOI. 0000..
United States Patent 3,261,358 SOURCE OF CURRENT FOR APPLICATION TO A PATIENT FQR OBTAKNING A THERAPEUTIC EFFECT Pierre Beats Bernard, 1 Rue Albert Sore], Paris, France Filed Oct. 28, 1963, Ser. No. 319,489 Claims priority, application France, Mar. 20, 1959, 39,226, Patent 1,219,027; Jan. 28, 1966, 40,104, Patent 77,046
8 Claims. (Cl. 128423) This application is a continuation-in-part of my prior application Serial No. 15,142, filed on March 15, 1960 entitled Apparatus Generating Currents for Use in Physiological and Physiotherapic Treatments, now abandoned.
The present invention relates to a current source or supply for furnishing electrical currents suitable for the therapeutic treatment of patients and more particularly to a current source which supplies alternately half-wave rectified pulsating current and full-wave rectified pulsating current.
Of the numerous physiological or therapeutic applications of electric currents, those which utilize rectified A.C. currents are particularly important.
When using electric currents for the physiological and therapeutic treatment of patients, it is found that the effects on sensitivity, muscular response and the related components of the behaviour of the patient decrease and may, in fact, completely disappear when the effective frequency of the electrical current increases.
Under such conditions, and if operating with a predetermined initial frequency leading to well-defined effects, if the frequency is doubled, it is observed that:
The effects are considerably reduced and disappear entirely;
They reappear however when the intensity of the current increases.
Conversely, if the frequency is reduced by one half, it is observed that:
The effects increase by a large amount and become painful;
They return to normal when the intensity is reduced.
In applications which require a periodic shifting between two frequencies, the benefit of the high frequency periods is thus lost unless the intensity is increased during application of the higher frequency.
correspondingly, if the intensity is satisfactory for the higher frequency, it is too large when the lower frequency is applied and this leads to a painful effect and an undesired amount of muscular contraction.
My invention has for its object to avoid these disadvantages and to produce an effectively uniform physiological activity in response to each of the two frequencies.
Briefly, the invention involves a modification in the intensity of a pulsating current in accordance with its eflective frequency, said modification comprising an in crease of the intensity when the frequency of peak repetition increases and, conversely, a reduction in intensity when the peak repetition rate decreases, the amount of the change in intensity being adjustable.
The invention includes the provision of cyclically operative switching means for changing from the lower pulse repetition rate to the higher rate, and vice versa, the switching means having a contact sequence which delays the increase in current intensity until after the increase in pulse repetition rate has taken place. Conversely, the current intensity is reduced before the reduction in pulse repetition rate is permitted to become effective.
When half-wave pulses are used, the frequency or repetition rate of the pulses is, for instance, equal to 60 cycles or pulses per second, and assuming the intensity of the current is measured with a DC. milliammeter,
it is found that there exists a lower limit of intensity below which the patient feels nothing and no muscular contraction is produced so that no immediate therapeutic effect can be obtained. If the intensity of the current is raised above the lower limit, the muscular contraction increases markedly while the patient feels the passage of the current and an upper limit is reached above which no application of current is practicable, since the pain cannot be endured by the patient. The intensity of the current should therefore be confined between said lower and upper limits.
When full-wave rectified current is used, the frequency or repetition rate of the pulses is double that for halfwave rectification. In the present instance, this would be pulses per second. However, the limits of intensity between which the applications of current are operable are widely different from those referred to hereinabove. The average intensity measured with a DC. milliammeter should be more than double that for halfwave rectification. Thus, when the lower threshold of perception is 2 milliamperes for half-wave rectification of alternating current having a frequency of 60 cycles, the threshold of perception becomes 4.8 milliamperes when full-wave rectification is used. In fact, if it is desired to obtain the same neuro-muscular response, for both halfwave and full-wave rectification, the full wave current intensity should be slightly more than twice the halfwave intensity.
It has been found that the sensation felt by the patient and the physiological effect are far more intense for a 60 pulses per second repetition rate than for a 120 pulse rate; said phenomenon is well known in the art, and when the frequency increases and reaches the range of high frequencies, the current no longer produces any muscular response.
Therefore, with a view to reducing the physiological effect which is possibly too large for the lower 60 cycle frequency, it is necessary to reduce the peak intensity of the pulses by means of, for instance, a condenser of a suitable capacity which forms a partial or smoothing filter for half waves fed at a 60 cycle frequency.
For certain therapeutic purposes, it is of advantage to apply in succession and in accordance with a predetermined schedule, the two repetition rates of 60 and 120 cycles; for instance the lower frequency is applied during one or more seconds, after which the higher frequency is likewise applied during one or more seconds, the lower frequency reapplied during one or more seconds, and so on.
In practice, when using a rectifier of the vacuum tube or solid state type, including two or four elements, it is possible to use alternately a single rectified alternation, say at a 60 cycle frequency, or both rectified alternations corresponding to a 120 cycle frequency. To this end, it is sufiicient to use a periodically or cyclically operated contact-maker and breaker which closes and opens the circuit feeding one series of the half wave pulses.
The control of the intensity of the current applied to the patient in accordance with my invention, may be obtained by a potentiometer as illustrated hereinafter.
In order to change the intensity of the current, I employ a contact-maker which short circuits a predetermined portion of a resistor so as to produce automatically the desired increase in intensity.
The contact-maker closes to increase the intensity immediately after closure of the contact providing full-wave rectification.
According to a second embodiment of my invention, the peak intensity of the half-wave rectified current is reduced by means of a shunt capacitor.
Several embodiments of the invention are described in detail in the following specification with reference to the accompanying drawings forming a part thereof.
Referring to the drawings:
FIG. 1 is a circuit diagram of a bridge type rectifier arrangement including a switch for transferring from half-wave to full-wave operation and vice versa.
FIG. 2 is a circuit diagram of a full-wave rectifier using a center-tapped transformer secondary winding, a switch being provided for transfer from full-wave to half-wave operation and vice versa.
FIG. 3 is a circuit diagram similar to FIG. 2 except that the transformer winding consists of two separate windings instead of a center-tapped winding.
FIG. 4 illustrates a potentiometer connected to control the intensity of the rectified current in an output circuit.
FIG. 5 is similar to FIG. 3 except that grid-controlled thermionic rectifiers with filament type cathodes are employed, the control grid of one of the rectifiers being shown connected to a switch for transferring from fullwave to half-wave operation and vice versa, the control grid of the other rectifier being appropriately biased for continuous half-wave rectification.
FIG. 6 is a circuit diagram illustrating a cyclically operative eccentric cam-actuated switch providing a sequential switching effect which assures that full-wave rectified current will be delivered to the output circuit before the intensity of the output current is increased, said figure including a circuit diagram of a potentiometer circuit for varying the current intensity in the output circuit by means of the cyclically operative switching mechanism, means being provided for varying the current intensity in the output circuit, separately adjustable means being provided for varying the intensity of the half-wave current with respect to the full-wave current.
FIG. 7 is a showing of a switch similar to that of FIG. 6 except that a single pole sequential double make contact arrangement is shown instead of a double pole sequential contact arrangement.
FIG. 8 is a circuit diagram showing a transformer with two secondary windings and two indirectly heated cathode diode type rectifier elements, the switching with sequential intensity control utilizing the cyclically operative contact arrangement of either FIG. 6 or FIG. 7.
FIG. 9 is similar to FIG. 8 except that the rectifier elements are of the solid state type and do not employ heated cathodes.
FIG. 10 is similar to FIG. 1 using four rectifier elements connected in a bridge arrangement, sequentially operative intensity control being obtained by the cyclically operative Contacts of FIG. 6 or FIG. 7.
FIG. 11 shows a cyclically operative transfer contact with make-before-break contact sequence.
FIG. 12 is a circuit diagram showing two rectifier elements energized by a transformer having a center-tapped secondary winding, a capacitor being connected by the contact arrangement of FIG. 11 to reduce the peak voltage of the half-wave rectified current.
FIG. 13 is a circuit diagram of a bridge type rectifier circuit using the cyclically operative contact arrangement of FIG. 11.
In all the figures, the same reference numerals designate similar parts and it will be observed firstly that the repetition rate or frequency of occurrence of peak volt ages in the case of a full-wave current is twice that of the half-wave current. Of course, for half-wave rectification, the frequency or repetition rate of the peaks is the same as the frequency of the power line from which the rectified current is derived. In the case of the full-Wave rectified current, the frequency of the peak repetition is twice the line frequency.
Referring to FIG. 1, four half-wave rectifier elements a, b, c, and d are shown connected in a bridge arrangement. With contacts 1 and 2 open in one arm, half-wave rectified current is obtained at output terminals U leading to the patient through the output control circuit shown in FIG. 4. With contacts 1 and 2 closed, the full-wave rectified current is obtained.
In FIG. 2, only two rectifier elements a and b are used in conjunction with a transformer T having a centertapped secondary, the switch 1, 2 cutting off the halfwave rectifier element b periodically.
FIG. 3 is similar to FIG. 2 except that the transformer has two separate secondary windings instead of a single center-tapped winding, the same references being retained for both figures. The arrangements according to FIGS. 1, 2 and 3 are associated with output intensity controlling means such as those illustrated in the following figures.
Thus, FIG. 4 shows a potentiometer P connected across the terminals u, in parallel with the full-wave and halfwave feeding means of any of FIGS. 1, 2 or 3. The movable contact c of the potentiometer P is periodically connected by a switch 34 with one of the terminals u to increase the intensity. The switches 12 and 3-4 are ganged in the manner disclosed hereinafter so as to close and open substantially simultaneously, but sequentially, to provide a cyclic increase and decrease of both intensity and frequency. The output terminals X are connected to the patient.
In principle the maximum and minimum average intensities should be in a ratio as between 2 or 2.4 to 1, but said ratio can be adjusted by moving the slider c.
FIG. 5 illustrates a complete circuit according to my invention. The transformer T feeds anode current through its two main secondaries s1 and s2 which are wound in opposite directions to the grid-controlled rectifying valves v1 and v2, the filament-type cathodes of which are energized from the auxiliary secondary s3. These rectifiers thus apply the successive alternations of the supply current across the terminals X of the output circuit leading to the patient. Three different switch connections illustrate how the full-wave or half-wave rectification may be selectively obtained. Of course, only one of the three connections will be used in practice. The switch 1, 2 is inserted in the secondary $2, the switch 1, 2' in the grid circuit of the valve v2, the switch 1", Z" in the cathode heating circuit for v2. The corresponding modification in intensity is obtained through the motor driven cam 6 which actuates either the contacts 1, 2 or 1', 2 or 1", 2", as the case may be, along with and the contacts 3", 4" which short-circuit the resistance R in the output circuit. The cam 6 provides a closing of contacts 1", 2" or 1, 2 or 1', 2' for full-wave operation slightly in advance of the closing of contacts 3", 4 for the increase in intensity. The sequence of the make and break operations is such that the current of higher intensity cannot be supplied to terminals X during the half-wave periods. The contacts maintain the half-wave current at reduced intensity throughout each entire period of its production and also during the initial and terminal portions of each production of full-wave current.
FIG. 6 shows a cam-actuated set of cyclically operative contacts, which includes, in addition to half-wave, full-wave control contacts 1, 2, or 1, 2' or 1", 2", a set of intensity control contacts 3", 4". The contact sequence is, as previously described, such that the half-wave, full-wave contacts 1, 2 or 1', 2' or 1", 2" make first and break last with respect to the intensity control contacts 3", 4 during each cycle to prevent the increase in intensity until full-wave current is previously made available. As in FIG. 5, the cam 6 is continuously driven by a suitable motor, not shown.
FIG. 6 differs from FIG. 5 in that the cyclical modification in intensity is obtained by making the switch contacts 3", 4" close a shunt between the slider C and one of the terminals of the potentiometer P In FIG. 5 and in FIG. 6, the triodes may of course be replaced by diodes or any other type of rectifier.
FIG. 7 illustrates a simplified contact arrangement wherein the separate contacts 2 and 3 of FIGS. 5 and 6 have been electrically connected together by mounting them on a common contact spring. The contact arrangement of FIG. 7 is not suitable for use with the arrangement according to FIG. 2, for example, because the halfwave, full-Wave control contacts 1, 2 and the terminals U are in separate circuits. By interchanging contacts 3 and 4 in FIG. 7 so that contacts 2 and 4 are connected together, it will be apparent that the single pole contact arrangement of FIG. 7 as thus modified, will be suitable for use in the case of FIGS. 3 and 6 instead of the double pole contact arrangement of FIGS. 5 and 6.
FIG. 8 illustrates two diodes D and D fed in opposite directions by the two secondaries of the transformer T, the contact 1, 2 in one of the diode circuits being cam controlled like contacts 1", 2" of FIG. 5 or FIG. 6, together with further potentiometer shunting switch contacts 3, 4 which are controlled like contacts 3", 4".
FIG. 9 shows two solid state rectifiers a, b connected to the outer ends of a single center-tapped secondary s.
FIG. 10 is similar to FIG. 1 and shows a rectifier bridge associated with a double potentiometer P P The cam, such as 6 (not shown), controls both the switch 1, 2 in a bridge arm and a switch 3, 4 in a shunt path leading to one slider C for the potentiometer P P the other slider C serving for output adjustment.
In FIG, 11, there is shown a cyclically operative set of cam-actuated contacts wherein contacts 1, 2 and 3, 4 are so arranged that contacts 3, 4 are open when contacts 1, 2 are closed and vice versa. The contact sequence is makebefore-break so as to be used with the arrangements according to FIGS. 12 and 13 to be now described.
As illustrated in FIG. 12, when contacts 1, 2 are open to provide half-wave current, contacts 3, 4 are closed to connect a shunt capacitor 5 across the serially connected resistors P and P and forming if required, a voltage divider or potentiometer. When the capacitor 5 is shunted across the resistors P and P the peak intensity of the half-wave current is reduced by a filtering action. When contacts 1, 2 are closed to provide full-wave current, the capacitor 5 is subsequently disconnected by the opening of contacts 3, 4 controlled by the same motor driven cam 6 as the switch 1, 2 so that an increased peak intensity of the full-wave current is applied to the output terminals X with respect tothe half-Wave peak intensity.
As noted above, the make-before-break contact seq nce ensures that the capacitor 5 will not be disconnected to increase the peak intensity until contacts 1, 2 have first closed to provide full-wave current. Conversely, the contacts 3, 4 close to connect the shunt capacitor 5 before the contacts 1, 2 open to furnish half-wave current the intensity of which must be reduced with respect to the full-wave intensity.
FIG. 13 is similar to FIG. 12 except that a four-element bridge type rectifier is used instead of two rectifiers associated with a center-tapped secondary winding as in the case of FIG. 12.
While I have shown and described What I believe to be the best embodiments of my invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.
What I claim is:
1. A source of current for application to a patient for obtaining a therapeutic efiect, said source comprising an alternating current energizing circuit, an output circuit for connection to said patient, a plurality of rectifier means, cyclically operative switching means, circuit means connecting said energizing circuit to said output circuit through said rectifier means, said switching means being connected to said circuit means to produce alternately a full-wave rectified current and a half-wave rectified current in said output circuit, a circuit element for reducing current flow in said output circuit, said switching means comprising contact means connected to said circuit element for continuously maintaining the intensity of said half-Wave current at a reduced value with respect to the intensity of said full-wave current throughout the entire period of production of said half-wave current and the initial and terminal periods of production of said fullwave current, and manually operable means for adjusting the relative intensities of said full-wave and halfwave currents with respect to each other whereby a unitormity of response of the patient to both currents is obtained.
2. A current source for obtaining an electrical current to be applied to a patient for obtaining a therapeutic effect, said source comprising an energizing circuit for connection to a commercial alternating current supply to be energized therefrom, an output circuit for connection to said patient, a plurality of rectifier elements, switching means including contact means cyclically operative between first and second positions, circuit means interconnecting said energizing circuit, said rectifier ele- I ments and said output circuit, said contact means being connected to said circuit means to supply said output circuit with full-wave rectified current in said first position and half-wave rectified current in said second position, a circuit element for reducing the current flow in said output circuit, said contact means being connected to said circuit element and sequentially operative to reduce the intensity of said half-wave current with respect to said full-wave current during the course of operation between said first and second positions, and manually operable means :for adjusting said intensities, whereby a uniformity of response of the patient to each current is obtained.
3. A cur-rent source according to claim 2, wherein one of said rectifier elements comprises a control \grid connected by said contact means for starting and stopping the operation of said one rectifier element in response to operation of said contact means between said first and second positions.
4. A current source according to claim 2, wherein said circuit element is a capacitor which is connected by said con-tact means in said second position thereof to reduce the peak voltage of said half-wave rectified current supplied to said output circuit by said circuit means.
5. A source of current for application to a patient for obtaining a therapeutic effect, said source comprising an alternating current energizing circuit, an output circuit for connection to said patient, a plurality of rectifier means, cyclically operative switching means, circuit means controlled by said switching means periodically connectin-g said energizing circuit to said output circuit through said rectifier means to produce alternately a full-wave rectified current flow and a half-Wave rectified current flow in said output circuit, said circuit means comprising means sequentially controlled by said switching means for continuously maintaining the intensity of said halfwave current flow, at a value slightly less than one-half the intensity of the full-wave current throughout the entire duration of said half-wave current flow and during the initial and terminal portions of said full-wave current flow.
6. A source of current for connection to a patient for obtaining a therapeutic effect, said source comprising: an alternating current energizing circuit; and output circuit for connection to said patient; a plurality of rectifier means; a set of contacts movable between first and second positions through an intermediate position, said contacts being connected to said energizing circuit, said rectifiers and said output circuit to supply said output circuit with [full-wave rectified current in said first position and half- Wave rectified current in said second position; circuit means connected to said contacts and to said output circuit to reduce the intensity of said half-wave rectified current in both said intermediate and second positions of said contacts; cam means continuously operative to actuate said contacts cyclically between said first and second positions; and manually operable means for adjusting the relative intensities of said full-wave and half? wave currents.
7. A source of current for application to a patient for obtaining a therapeutic effect, said source comprising an alternating current energizing circuit, an output circuit adapted for connection to said patient, a plurality of rectifier means, cyclically operative switching means, and circuit means controlled by said switching means periodically connecting said energizing circuit to said output circuit through said rectifier means to produce alternately a full-wave rectified current flow and a half-wave rectified current flow in said output circuit, a resistor in said output circuit, contact means in said switching means for short-circuitin-g said resistor, said resistor being connected in said output circuit to reduce the current flow therein throughout the entire interval of passage of the half-wave current flow and the initial and terminal portions of intervals of full-wave current flow, thereby to References Cited by the Examiner UNITED STATES PATENTS 3/1949 Bernard 124421 X 6/1958 Paust 128420 X OTHER REFERENCES Journal of Scientific Instruments, vol 20, No. 3, pp. 37-45, March 1943.
RICHARD A. GAUDET, Primary Examiner.
W. E. KAMM, Assistant Examiner.