Electrical muscle stimulator

3,472,233

Oct. 14, 1969

R. I. SARBACHER

ELECTRICAL MUSCLE STIMULATOR Filed Dec. 2. 1966

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United States Patent Office

3,472,233

Patented Oct. 14, 1969

472 233 ELECTRICAL MUSCLE STIMULATOR Robert I. Sarbacher, 2503 Tracy Place NW., Washington, D.C. 20008

Filed Dec. 2, 1966, Ser. No. 598,845 5

Int. Cl. A61n 1/00

U.S. Cl. 128—422 7 Claims

ABSTRACT OF THE DISCLOSURE ₁₀

An electrical muscle stimulator having an electrode assembly of two body contacting electrodes is energized by a miniaturized pulse generator. The pulse generator is mounted directly on the electrode assembly to provide an integrated unit; and the assembly is foldable and has ¹⁵sealing means, so that when stored the body contact surfaces of the electrodes are completely enclosed.

The present invention relates to the field of electrical muscle stimulation, and particularly to an integrated electrode pad and pulse generator for application to the body of a user as a self-contained unit.

Muscle manipulation by use of electrical pulse stimula- 25 tion is well known, and numerous systems have been devised and used for this purpose. The most prevalent approach in this field is to provide an electrode pad, which comprises two separate electrodes. Each electrode usually includes a body contacting sponge backed with a 30 wire gauze, and the two electrodes are joined by means of a flexible web to form a unitary electrode pad. A separate electronic pulse generator is used to develop the muscle stimulating electrical pulses at a desired frequency, duration and power, and the output of this generator is cou- 35 pled by wire leads to the electrode pads, one lead to each electrode. Binding posts or other connector structure are mounted on the electrodes to facilitate the coupling and decoupling of the pulse generator to the electrode pad structure. Thus in use, the electrode pad is placed on ⁴⁰the body of the user, with the two electrode sponges in contact with, skin of user, and located where desired to stimualte the muscles therebetween. Preferably the sponges are wetted with water to improve the contact between the body and the electrodes. With the generator wired to the ⁴θ elecrode pad, the desired electrical pulses are applied across the two electrodes of the pad, and hence across the body muscles between the two electrodes, causing these muscles , to contract and relax in response to the pulses applied from the generator. ⁵θ . Obviously the user is restricted in mobility during this treatment, because of the wire connection between the body electrode pad and the pulse generator. Additionally, the system is not readily portable, and therefore the locale of use is restricted, because the user must have available both the body electrode pad and the separate pulse generator in order to utilize the system.

In accordance with the present invention, an electronic pulse generator circuit is incorporated directly in the body- electrode pad, so that only a single unit is required, ⁶⁰instead of two separate devices. Furthermore, the pulse generator circuit is miniaturized and battery operated so that it will not unduly increase the bulk of the body electrode pad. Thus, because of its ready portability, the unit may be easily carried by the user for use at any ⁶⁵time and locale. Additionally, the unit may be applied to a desired area of the body, and strapped or otherwise affixed thereto, and the used may proceed with the normal activities with the unit operating, or it may be turned off and on at will. This integrated pad and pulse generator ⁷⁰is further constructed so as to be folded upon itself with the electrode pads, particularly the body contact areas thereof, internal of the fold. The pad is then sealed, to enhance the portability of the unit by protecting the sponge or other material forming the body contacts from dirt, dust, and other contaminants, and additionally by retaining moisture in the sponge contacts so they are readily available for use at all times without necessarily requiring a rewetting of the sponges for each use.

It is accordingly one object of the present invention to provide an electrical muscle stimulating system having an integrated body contact electrode pad and electrical pulse generator circuit.

Another object of the present invention is to provide such a system having a self-contained power supply.

And another object of the present invention is to provide such a system which includes a sealed housing for protecting the body contact elements.

Other objects and advantages of the present invention will become apparent to those skilled in the art from a consideration of the following detailed description of one exemplary embodiment of the invention, had in conjunction with the accompanying drawings, in which like numerals refer to like or corresponding parts, and wherein:

FIG. 1 is a face view of an open integrated electrode pad and pulse generator constructed in accordance with the present invention;

FIG. 2 is a sectional view of this device taken along the line 2—2 of FIG. 1;

FIG. 3 is a perspective view of the electrode pad and pulse generator folded over and sealed; and

FIG. 4 is a wiring diagram of a pulse generator circuit that mav be utilized in the present system.

Referring to the drawings, it will be seen that the present system comprises a body electrode pad structure 10 having a first electrode section 11 and a second electrode section 12, joined by a flexible web 13. The length of the connecting web 13 is of course selected to provide a convenient span between the electrode sections 12 and 13 over the body of the user, as is well understood in the art.

Electrode section 11 is formed with an open faced envelope 14, housing a flexible conductive wire grid or screen 16, and over which is a sponge layer 15. The sponge layer 15 affords the body contact element of this electrode section. Electrode section 12 is identical to electrode section 11, and therefore need not be further described than to state that the corresponding parts have been numbered correspondingly to section 11. The envelopes 14 of the two electrode sections, and the flexible connecting web 13 may be fabricated of flexible plastic or leather, or any other suitable fabric. As thus far described the body contact electrode assembly is substantially conventional.

On the back of electrode section 11 a pocket 17 is formed by the envelope housing 18. This envelope contains the miniature electrical components making up the pulse generator circuit diagrammatically illustrated in FIG. 4. A few of these components have been schematically indicated by the elements 20 in envelope 18. One output lead of the pulse generator circuit is indicated by the numeral 21, and it connects the pulse generator to conductive screen 16 of electrode section 11, while the other output lead 22 of the generator passes through the web 13 and connects the pulse generator to conductive screen 16. Preferably all the components in the pulse generator circuit including the battery, transistors, capacitors, diodes and resistors, are mounted on a board 23, which may of course carry a printed circuit for these components. The assembly circuit, connected to leads 21 and 22 is thus readily insertable in the pocket 17 of envelope 18 through the flap slot 24, and is readily removable therethrough for repair of the circuit and

3,472,233 ³replacement of the battery. Also my merely folding flap 24 back, the circuit control dials on board 23 are exposed, i.e., the on-off switch, and the controls for the variable capacitors and resistors indicated in FIG. 4.

When the electrode pad assembly is open as shown in FIG. 1, its periphery is surrounded by a conventional slide fastener 30, so that when the pad assembly is folded over about the hinge portion 31 of the connecting web 13, to place the open faces of the electrodes together in juxtaposed position, the slide fastener can be closed, thereby substantially sealing the interior of the folded pad assembly, as shown in FIG. 3.

A schematic circuit diagram of one illustrative embodiment of a pulse generator housed in the pocket 17, is shown in FIG. 4. This illustrative circuit is adapted from a pulse generator as described in Electronics, Dec. 21, 1962, vol. 35, No. 51, page 47. It comprises essentially a free running multivibrator 50 with separate variable controls for pulse width and for pulse repetition rate. The variable controls are variable resistor-capacitor networks RiCi and R₂C₂. The elements RiCi may be ganged together for unison adjustment, or they may be separately adjustable; and the same is true of the elements R₂C₂. The network RjC, controls the time duration of the positive going portion of the multivibrator output, while R₂C₂ controls the time duration of its negative going portion. Therefore, if the output is selected to be the positive going portion, the network RiC, is the pulse duration control, and network R₂C₂ is the pulse repetition rate control. Preferably, the resistance and capacitance values of the pulse generator are selected to provide a gradual rise time for the output pulses, which is more comfortable for the user than a sharp rise time.

The multivibrator output may conveniently be taken at point 51, by connecting this point to one of the body electrodes, and connecting the other electrode to ground. Point 51 is shown connected to body electrode 11 by lead 21 (corresponding to lead 21 in FIG. 2), and body electrode 12 is shown connected to ground by lead 22 (corresponding to lead 22 in FIG. 2). With circuit 50 thus connected to the electrode pad 10, the multivibrator output is applied across the body electrodes 11 and 12, and when these electrodes are applied to the body of a user, the muscles between the electrodes are stimulated to contraction and relaxation in unison with the output pulse pattern of the multivibrator 50, as is well understood in the art. A variable resistor or potentiometer 52 is connected across the electrode pad 10 to control the amplitude of the pulses applied to the electrodes 11 and 12.

To use the muscle stimulator of the present invention, the pad assembly is unzipped and opened to the position shown in FIG. 1. The sponges 15 forming the body contact areas of the electrodes 11 and 12 are moistened with water to facilitate good electrical contact with the skin of the user. The pulse generator circuit 50 is turned on, and the variable resistor-capacitor networks RiCi and R₂C₂ are adjusted to provide the desired pulse width and pulse repetition rate or frequency. The electrode assembly is then placed and held against the body of the user in the desired area to stimulate the muscles between the two contact faces 15, and the potentiometer 52 is adjusted to provide the desired pulse amplitude.

Obviously, the electrode assembly can be held in place against the body of the user either by hand, or by means of a belt or other mechanical aid suitable to the location of the body to which the pad assembly has been applied.

When the user has completed the desired treatment, the assembly is removed from the body, folded to juxtapose the two electrode contact surfaces 15, and the slide fastener is closed. Closure of the slide fastener seals the body contact surfaces 15 against dirt and other contamination, and at the same time decreases substantially the rate of evaporation of moisture from the sponges 15. Therefore, for many subsequent uses of the muscle stimulator. it will not be necessary to clean the body contact areas, nor will it be necessary to wet the contact sponges 15.

Accordingly there is provided a self-contained, integrated electrical muscle stimulator, wherein the body contact areas are sealed when the device is not in use. The specific embodiment of this invention herein described is set forth merely for purposes of example to enable a full understanding of the invention, and various changes; modifications and variations will be apparent to those skilled in the art. Such deviations from the present disclosure as are embraced by the spirit and scope of the appended claims are contemplated as being within the purview of the present invention.