US 2838672 A
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Description (OCR text may contain errors)
June 10, 1958 R, PAUST 2,838,672
` ELECTRO-THERAPY GENERATOR Filed June 29. 1954 2 Sheets-Sheet 2 2,838,672 ELECTRO-THERAPY GENERATOR Lawrence R. Paust, Chicago, Ill.; Leah M. Paust, adminstratrix of said Lawrencev R. Paust,fdeceased, assignor to Physical Medicine Products Co., Kansas City, Mo., a partnership Applicationl'uue 29,1954, Serial No. 440,049 4 Claims. (Cl. Z50-36) This invention is concerned withk anelectro-therapy generator and more particularly with an electro-therapy generator which automatically provides an output comprising a sequence of signals of different character.
The electrical treatment or stimulation of muscles is a rapidly growingeld and new types of treatment and new applications are constantly being found. Generally speaking, an electro-therapy generator includes a source of relatively low frequency alternatingr current preferably States Patent having a pulsed rather than a sine wave form. Direct current also has some specific applications but is not as widely used as pulsed alternating current. Electrotherapy treatments are primarily designed to permit the exercise of muscles which for one reason or another could not otherwise be suiciently exercised as to prevent atrophy in the case of paralysis or other temporary immobilization and in the treatment of strains, sprains and dis locations to speed the reduction of the attendant swelling. It has been found that certain combinations or sequences of treatments are sometimes much more effective than continuous treatment of a single type.
l have devised and disclose and claim herein a novel electro-therapy generator which provides a variety of types of signals and automatically changes the type of signal available at regular intervals.
One feature of the invention is the provision of an electro-therapy generator comprising means for producing a plurality of types of electro-therapy signals, means for utilizing the signals land control means for automatically changing the type of signal available at the utilizing means.
Another feature is that the electro-therapy generator comprises an oscillator, means connectable to the oscillator for causing a plurality of types of operation thereof, output circuit means connected to the oscillator and control means for connecting both of the means to the oscillator for providing a sequence of signals of predetermined character at the output means.
Another feature is that the generator includes an electron tube having a control element, a rst circuit connectable to the control element for causing operation at a fixed frequency, a second circuit connectable to the control element for causing operation at a variable frequency, a double-throw switch for effecting alternate connection of one or they other of the circuits to the control element of the tube, motor-driven cam means for controlling the operation of the switch at regular intervals and means for utilizing the oscillations produced in the electron tube.
Still another feature is that means are provided for equalizing the intensity of the signal `available in the utilizing means'throughout the sequence of the operation of the generator.
Further features and advantages will readily be apparent from the following specication and from the drawings, in which:
Figure 1 is an elevation view of the control panel of "ice an electro-therapy generator embodyingthe invention; and
Figure 2 isa schematic drawing. of thecircuit of the electro-therapy-generator.
The electro-therapy generator described herein is basically similar to that disclosed and claimed speciically in copending Paust and' De Gro application, Serial No. 283,082, iiled April 18, 1952, now Patent No. 2,764,683, issued Septemberi25, 1956. As in the generator shown in that application, three different types` of outputs, pulse, surgey andltetanizing, areprovided. The three different types of signals are made available at a pair ofV output jacks to which suitableipads may be connected forapply.- ing the signals to. the patient. Means are provided, however, which make theseivarious outputsignals available sequentially and automatically at -a desired vpredetermined repetition rate. his permits treatments to be given continuously with a single type of signal and also permits treatments to be givenwith different types of signals occurring in an automatic sequence.
Referring now to the drawings, the particular embodiment of the electro-therapy generator shown herein will be described. The values of the various circuit elements and thev type of 'circuit shown, illustrate merely one embodiment of the invention and many modifications will readily be apparent to those skilled in the art.
The electro-therapy generator may be energized by connecting leads 1t) and 11 to a suitable source of power such as 110 volts A. C. The. primary` winding 12a of a power supply auto transformer 12 is connected across the line through fuse 13 and timer switch 14, the timer switch 14 permitting treatments to be given for a predetermined period of time and then automatically turning off the generator.
Apower oscillator 15 is provided in the generator and may be a type 1619 pentode. The filament 16 of the tube is connected to a tap 12b on the power transformer and an indicator light 17 is connected across the lament to indicate to the operator when the generator is energized. The. anode 18 of the oscillator is connected through primary winding 19a of. combined feedback and output transformer 19 to the `secondary winding 12C of power transformer 12; and screen grid 20 of the tube. is connected f directlyto secondary winding 12e.
A feedback Winding 19b is provided on transformer 19 and has one terminal connected to the common line 11, to which the power transformer and one side of the filament 16- are returned. The other terminal of winding 19b is connected through feedback capacitors 22a and 22b to the control grid 24 of tube 15. Switch 23 is provided to determine whether oneor both of the capacitors 22 are connected in the feedback circuit, providing a rough frequency control.
Control grid. 24 is returned to the common side of the filament, line 11, through element 25a of doublethrow switch 25', which serves to determine whether the generator operates automatically or not, and one or the other of two operation controlling circuit means, the first comprising variable resistor 26, 1.25 megohms, and resistor 27, 10,000 ohms, in series, and the second comprising resistor 28, 5,000 ohms. When the first control circuit, resistors 26 and 27, is connected to the control `grid 24 of oscillator 15 the frequency of oscillation may be manually adiusted as desired; while when the second circuit, resistor 28, is used fixed frequency oscillations are provided.
Two output circuits are provided so that treatments may be applied to two different points on the patient at the same time. The iirst includes Winding 19e ontransformer 19, amplitude control resistor 30, 3,000 ohms, and. output jack ,3.1. The second circuit is substantially identical, comprising winding 19d, amplitude control resistor 32, 3,000 ohms, and output jack 33. Both of the output circuits are completed through contacts associated with relay 34, the operation of which will be described later. Assuming that switch is thrown to the in position (the position for automatic sequential output operation), the feedback circuit of the oscillator will be completed through double-throw cam-operated switch 35. When the switch'35 is in the lower position closing contact a as shown, the first circuit, comprising resistors 26 and 27, will be connected in the circuit while when cam 36 moves switch 35 to the upper position closing contact 351), the second circuit, resistor 28, will be Vconnected to control grid 24. At the same time the output control relay 34 is connected from line 11 through camoperated switch 37, section 38h of time control switch 38 and one or the other of cam-operated timing switches 39a, 39b and 39C to line 10. Switches 39m, 39b and 39C are operated respectively by cams a, 40b and 40C all of which are driven concurrently by motor 42.
The motor 42 is energized through a section 38a of switch 38 and runs at any time the switch is in other than the zero position. Cams 36 and 43, which operate switches 35 and 37 respectively, are also driven by motor 42 through a reduction gearing arrangement 44.
Assuming that switch 25 is in the in position and that timing switch 38 is set to either l, 3 or 6, the output appearing at terminals 31 and 33 will include the three different types of operation of the device, surge, pulse and tetanizing currents, in a repeating sequence for so long as timer 14 permits the generator to continue in operation,
As shown in the drawings, cam switch 35 is in the lower position so that contact 35a is closed connecting variable frequency controlling resistors 26 and 27 to grid 24 of the oscillator. This circuit provides a pulsed output at a frequency of from l to 400 cycles per second with switch 23 connected in the position shown or if switch 23 is opened, up to 700 cycles per second with only capacitor 22a connected in the circuit. The actual number of pulses produced during any given period is, however, considerably less than the nominal frequency of the oscillator due to the inherent rectifying action obtained by using the straight transformer power supply.
As cams 36 and 43 are driven in a clockwise direction by motor 42, switch 37 will close, contact 35a of switch 35 will open and contact 35b thereof will close at approximately the same time. Switch 35 acts to change the operation controlling portion of the feedback circuit of the oscillator, substituting xed resistor 28 for resistors 26 and 27,-the oscillator providing oscillations at a fixed frequency.
In addition, the energizing circuit of relay 34 will alternately be made and broken through the action of camoperated switch 39a (if switch 38 is in the l position). Contact 34a of relay 34 alternately makes and breaks the circuit of output 31 while contacts 3412 and 34e` are similarly connected in the circuit of output 33. If switch is in the position shown in the drawing, outputs 31 and 33 are energized simultaneously, Vwhile if it is moved to the other position, connecting contact 34b of the relay in the circuit, the outputs are switched alternately.
Each of the cams 40a, 40b and 40C are designed to provide a different time period for the operation of relay 34, as for example one second intervals, three second intervals and six second intervals indicated on the drawings. Other periods may be provided if so desired.
After a period of surge type treatment, cam switch 37 isV again opened and a continuous output at a fixed frequency, as determined bythe position of switch 23 and the size of resistorY 28, appears at the output terminals. If'switch 45` is in the alternate position as shown, the constant frequency will appear only at outlet 31, while if switch 45 is in the opposite position the oscillations will appear continuously at both outlets 31 and 33.
Cams 36 and 43 and step-down gearing 44 are so arranged that a cycle of three one minute treatments are provided. That is, there will first be an output of pulse type treatment at a frequency determined by the etting of variable resistor 26, then a period of surge type treatment at a rate determined by the setting of switch 38 and then a period of ment. ln order to accomplish this in the embodiment of the invention illustrated, cam 36 has a portion corresponding to cut away so that switch 35a is closed for 120 of the rotation thereof, a period of one minute, while switch 35b is closed for 240 of the rotation thereof, a period of two minutes. Cam 43 similarly has a portion corresponding to 120 cut away and permits the closing of switch 37 for a period of one minute during cach cycle. The relative positions of cams 36 and 43 are adjusted so that switch 37 is closed during the first minute of the two minute period during which switch 35b is closed.
When switch 25 is thrown to the out variable frequency control, resistors 26 and 27 are connected in the circuit through section 25a thereof while section 25b shorts across switch 37 connecting relay 34 to section 38h of switch 38 at all times.
Section 38e of switch 38 serves to complete the circuit to outlet 33 should switch 45 be left in the alternate position when switch 38 is turned to zero.
The value of resistor 28, 5,000 ohms, is so correlated with resistors 26 and 27, 1.25 megohms and 10,000 ohms respectively, that the relative intensities of the o-utputs occurring during different portions of the cycle of operation are approximately the same so that the muscle stimulation provided may be of the maximum permissible amplitude at all times.
While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.
l. An electro-therapy generator of the character described, comprising: an electron tube having a control element; a first circuit connectable to said control element for causing operation of said oscillator at a fixed freqency; a second circuit connectable to said control clement for causing pulsed operation of said electron tube at a different frequency; a double-throw switch for effecting alternate connection of one and then the other of said circuits to the control element of said electron tube; motor-driven cam means for controlling the operation of said switch at regular intervals; and means including a contact device connected to said tube for applying the oscillations to a patient.
2. An electro-therapy generator of the character described, comprising: an electron tube having a control element; a first circuit, including a first resistance, connectable to said control element for causing operation of said oscillator at a fixed frequency; a second circuit, including a second resistance larger than said first resistance, connectable to said control element for causing pulsed operation of said electron tube at a different frequency; circuit means including a contact device connectable to said tube for applying the oscillations to a patient; doublethrow rst switch means for effecting alternate connection of said first and second circuits to the control electrode of said tube; second switch means for effecting connection of said contact device to said electron tube; a motor; a rst cam driven by said motor for effecting operation of said first switch means to connect sai-d first and second circuits alternately to said control electrode of said tube; and a second cam driven by said motor and associated position, the
one minute of tentanizing treatwith said second switch means to control the connection of said contact device to said electron tube. p
3. An electro-therapy generator of the character described in claim 2, wherein said rst circuit is connected to said control element for a period longer than the second circuit is connected thereto, and the connection of the contact device to the electron tube is periodically interrupted during a portion of the time said first circuit is connected to the control element.
4. An electro-therapy generator of the character described, comprising: an electron tube having a control element; means connectable to the control element of said tube for causing oscillation at a xed frequency; means connectable to the control element of said tube for causing pulsed oscillation at a different frequency; means, including a contact device connectable to said tube for applying said oscillations to a patient; control means for automatically connecting one and then the other of the rst two of said means alternately to the control element of said electron tube at predetermined intervals, one of said means being connected to said control element for a longer period than the other; means vfor periodically interrupting the connection of said contact device to said electron tube during at least a portion of said longer period; and a second output circuit including a contact device connected to said tube for applying said oscillations to a patient, first switch means for periodically interrupting the connection of said output circuits to said oscillator, and second switch means in said output circuits and movable between a rst position in which the connection of said output circuits is interrupted simultaneously and a second position in which the connection of said output circuits is interrupted alternately.
References Cited in the le of this patent UNITED STATES PATENTS 2,004,751 Fischer et al June 11, 1935 2,503,668 Hart Apr. 11, 1950 FOREIGN PATENTS 387,518 Great Britain Feb. 9, 1933 435,547 Great Britain Sept. 16, 1935 654,823 Great Britain June 27, 1951 OTHER REFERENCES Electronic Engineering, July 1945, pp. 585-588 and 608.