Flexible therapeutic pad and vibratory armature therefor

Abstract

A vibratory therapeutic pad has an armature lying in a central plane, composed of a plurality of resilient ferrous metal strips each overlapping the next and encased in a body of foam-type material attached to the armature strips by adhesive. The over-lapped parts of adjacent strips are also adherent to each other. This assembly of the armature embedded in the compliant foam body is inserted within an outer assembly comprising a sheet over which a coil is wound with foam material around the outside of the coil. Adhesive holds the coil conductors to the sheet and to the foam body. The pad can be bent or shaped to fit various parts of the human body and the vibration of the armature is substantially noiseless. Application of alternating current to the coil produces an alternating magnetic field through the armature which causes the armature strips to vibrate, and heat is produced to an extent permitted by thermostats in the circuit of the coil.

Description

This invention relates to therapeutic pads and more particularly to such pads capable of vibrating.

Therapeutic pads for treatment of parts of the human body are well-known. They commonly comprise an electrical heating element with an associated thermostat arrangement to control temperature and are commonly adapted to be fitted to a portion of the body. Therapeutic pads capable of vibrating have also heretofore been known. Such vibratory pads have ordinarily been constructed with an armature of a relatively rigid spring metal piece adapted to be vibrated about a relaxed or normal position. Ordinarily such vibrator armatures have been constructed in an established shape depending upon the intended use for the pad, and therefore could not be bent or shaped to a configuration other than that established by the configuration of the armature.

An exception to vibratory pads of pre-established shape is that disclosed in my U.S. Pat. No. 3,664,332 issued May 23, 1972 entitled "Therapeutic Vibrating Pad." Pads according to that patent differ from previously known vibratory pads in that they are capable of being shaped to conform with various parts of the human body. This was accomplished according to that patent by provision of an armature comprising a plurality of overlapped strips of magnetic material fastened near their ends to a bendable frame and separated from each other and located in a magnetic field so that the magnetic field distorts each strip from its relaxed position independently of the other strips. Thus, by use of a magnetic field which is alternating, as produced by a coil carrying alternating current, the armature comprising the overlapped strips is vibrated at a frequency dependent on the frequency of the alternating current.

In accordance with the present invention, there is provided a therapeutic pad of the vibratory type adapted to be bent and conformed with the shape of parts of the human body, which has a number of advantages over that disclosed in U.S. Pat. No. 3,664,332. Among these advantages are: quietness of operation; greater flexibility for conforming to various shapes; and absence of abrasion points which could create discomfort for the patient.

The present invention is carried out by provision of an armature assembly comprising overlapping resilient strips of magnetic material to provide a nearly flat armature embedded on both sides by a thickness of compliant material such as a foam material. According to a preferred feature the compliant or foam material is secured to the armature strips by an adhesive and preferably also the overlapped portions of strips are secured to each other by adhesive. Although the armature lies generally in a plane within a magnetic field the individual strips in their relaxed condition are somewhat oblique to the general plane of the armature, with the result that upon generation of an alternating field the individual strips vibrate accordingly. The compliant material such as a foam material is sufficiently soft and compliant that it does not prevent the vibration of the strips, as the compliant material is readily capable of sufficient distortion to permit the vibration.

The embedding of the armature within the compliant material does, however, have the beneficial effect of silencing the noise which would otherwise occur from vibration of the strips, especially when the overlapped portions of the strips are adhered to each other by the adhesive. In consequence, there is substantially no noise associated with use of this vibratory pad.

Moreover, since the armature strips are not fastened or riveted at any position to any frame, the pad is more flexible than that according to U.S. Pat. No. 3,664,322. Furthermore, the absence of fastening rivets or the like to fasten the strips to a frame, such as in U.S. Pat. No. 3,664,332 makes for greater comfort to the patient as well as more flexibility, because if the assembly were by means of rivets or fasteners, the rivets would have to be long enough to permit such degree of flexibility as is desired. But the longer the rivets, the more prominent become the abrasion points and the greater the discomfort to the patient.

For vibrating the armature, there is employed a coil to be energized by a suitable electric power source such as 110 volts alternating current, commonly used in homes and buildings. The alternating current through the coil produces heating of the part of the body of the patient to which the pad is applied, thereby rendering beneficial therapeutic effect.

The foregoing and other features of the invention will be better understood from the following detailed description and the accompanying drawing, of which:

FIG. 1 is a plan view of a preferred form of pad embodying this invention shown with parts broken away to reveal layers of the structure;

FIG. 2 is a cross-section view taken at line 2--2 of FIG. 1;

FIG. 3 is a cross-section view taken at line 3--3 of FIG. 1;

FIG. 4 is an enlarged view in cross-section showing a detail taken at line 4--4 of FIG. 1;

FIG. 5 is a cross-section view taken at line 5--5 of FIG. 2; and

FIG. 6 is a cross-section view of an enlarged detail taken at line 6--6 of FIG. 1.

The therapeutic pad shown in the drawing comprises a covering envelope 10 of a flexible material such as vinyl rubber which for convenience may be made in two parts 10a and 10b cemented together at the median periphery 10c so that the sheet material 10 provides an enclosure within which are placed the other elements of the pad. The components inserted within the outer enclosure 10 are structured around an armature 11 assembled from a number of resilient strips 11a, 11b, . . . 11n. The strips are of magnetic material, preferably a thin spring steel, and all strips are of the same length which is somewhat less than the width of the enclosure 10. The strips are all of the same width and overlap each other as best seen in FIGS. 2 and 4. The assembly of strips is arrayed along the median plane within the enclosure 10, but due to the overlapping of the adjacent strips, each individual strip is slightly oblique to this median plane. The armature assembly 11 is held in its position by means of thicknesses 12 and 13 of foam material such as polyurethane foam of a light weight cellular structure placed over opposite sides of the armature 11. Thicknesses 11 and 12 are sometimes called a "compliant material."

The surfaces of the armature strips are secured to the adjacent respective surfaces of the foam material 12 and 13 by layers 14 and 15 of adhesive material as seen in FIG. 4. This adhesive is preferably applied in liquid or semi-liquid form and may be of a type which sets to a firmer consistency, although it preferably does not completely solidify. There are also provided through each of strips 11a through 11in, a number of holes 16 and 17 as shown in FIG. 1. Each end strip 11a and 11n is provided with one hole 16 located near one end of the strip and at the part of the width of the strip which overlaps the next adjacent strip. These end strips are also each provided with one hole 17 located near the opposite end of the strip from that containing hole 16 and also positioned at the portion of the width of the strip which overlaps the next adjacent strip. Each of the other strips 11b through 11n contains two holes 16 near the one end of the strip and two holes 17 near the opposite end of the strip, each such hole being positioned at the part of the strip which overlaps the next adjacent strip as seen in FIGS. 2 and 4. Corresponding holes 16 at overlapping parts of adjacent strips are positioned to be aligned with each other, and corresponding holes 17 are similarly aligned. The purpose of these aligned holes is to permit adhesive material 14 and 15 to flow into these holes and from the holes to move into the interface region between overlapping parts of adjacent strips. Such flow between the strips is assisted by capillary action. When the adhesive material then sets to a firmer consistency, adjacent overlapped strips of armature 11 are adherent to each other and to the foam layers 12 and 13.

There is placed around the assembly of armature 11 sandwiched between the foam material 12 and 13, and outer assembly comprising a rubber-like sheet 18, a coil of electrically conducting wire 19 and a layer 20 of foam material. The sheet 18 of rubber-like material may be of a vinyl rubber or the like, around which there is wound the coil 19 of wire which should have an insulating covering such as enamel to prevent electrical connection between adjacent turns. An adhesive material 21 similar to adhesive 14 and 15 is placed on the side of sheet 18 which supports the coil and preferably this adhesive material is placed there before the coil is wound over the sheet. Additional similar adhesive material 22 is placed over the coil 19 so that the foam layer 20 adheres to the coil. Preferably the adhesive material is one which, when applied, is flowable enough to flow into the spaces between the turns of the coil as illustrated in FIG. 6 so that when the adhesive sets to at least some degree it securely holds together the layers 18 and 20 to opposite sides of the coil.

A convenient manner of assembling the structure is to make the inner assembly of parts 11, 12 and 13 and the outer assembly of parts 18, 19 and 20 separate from each other and then insert the inner assembly of elements 11, 12, and 13 within the outer assembly.

Before applying the foam layer 20 over the coil there is applied over the coil an arrangement of thermostats and electrical connections to the coil ends. This electrical circuitry comprises a plug 23 of an ordinary well-known type for plugging into an electric outlet, to which are connected two conductors 24 and 25 as seen in FIG. 5. Conductor 25 connects to one end of the coil and is protected by a suitable sleeving represented generally by numeral 26, which represents a suitable covering for protection against mechanical injury. The other conductor 24 has connected into it at spaced intervals a number of thermostats 27 at positions spaced from each other and arranged in series along the conductor. The conductive part of the line designated 24a leaving the last one of the series arranged thermostats 27 is carried to the opposite side of the coil and has connected into it a number of spaced series arranged thermostats 28 in a manner similar to the connection arrangements of thermostats 27. The portion 24b representing the conductor attached to the end of the last thermostat 28 is connected to the opposite end of the coil 19 from that to which conductor 25 is connected.

The thermostats may be of any well-known type and require no detailed description here. Their contacts are arranged so that they are normally closed to provide a complete circuit through the coil to the source of electric power so that current passes through the coil when the plug 23 is connected to a suitable outlet. But when any part or all of the coil is heated to a temperature which raises the temperature at any one or more of the thermostats to a predetermined critical value, the contacts of such thermostat open to open the entire circuit through the coil so that heating current no longer flows through the coil. When the coil cools down sufficient to permit all of the thermostat contacts to become closed, the circuit is again completed to warm up the coil again.

The source of power to which the heating pad will be connected will be an alternating current source, ordinarily 110 volts at 60 cycles per second. The effect of the alternating current is to cause vibration of the armature at a frequency dependent upon the frequency of the alternating current power source. The armature is enabled to vibrate because it is not a rigid structure nor is it rigidly secured to any frame. Instead, it is made up of resilient strips of a thinness and mass and resilience which permits the vibration within the soft resilient body or matrix formed by the foam air cell layers 12 and 13, which being composed largely of air cells are freely deformable according to the vibrations of the armature strips.

Moreover, although the principal plane of the armature 11 lies in the median plane of coil 19, best seen in FIG. 3, the individual strips do not lie in this plane, but rather are somewhat oblique to this plane as best seen in FIGS. 2 and 4 which illustrate the relaxed position of the strips. This relaxed position is that which the armature strips tend to assume at the periodic null current conditions of the alternating current cycle, but during each cycle the alternating current rises to a maximum first in one direction and then after passing through the null current point rises to a maximum in the opposite direction. During the half cycles when current is flowing, there is created a magnetic field first in one direction and then in the other direction through the coil in a well-known manner, and regardless of the direction of the magnetic field at any instant, the effect is to cause the magnetic field to concentrate through the armature and to exert a force on the armature tending to straighten it out toward its position which provides the least magnetic reluctance. Thus, the effect is to twist each strip which lies oblique to the central plane when relaxed, to a position somewhat less oblique to the central plane. Thus, the armature strips vibrate depending on the frequency of the current, which being ordinarily 60 cycles per second will cause the armature strips to move 120 cycles per second. Because of the armature strips being secured adhesively to each other and to the foam bodies 12 and 13, the vibratory action is silent.

The expressions "heat" and "heating" is used herein encompasses any manner of heat generation resulting from the alternating current through the coil including ohmic resistance type heating and induction type heating.

It will be recognized that by the present invention there is provided a vibratory therapeutic pad which can be readily bent and flexed to various desired shapes, and caused to vibrate silently in any such shape and without bumps or abrasion points which, if present, could create discomfort for the patient. By reason of the silence of operation, neither the patient nor those around him will be annoyed by noise from the pad.

It will be understood that the embodiments of the invention illustrated and described herein are given by way of illustration and not of limitation, and that modifications or equivalents or alternatives within the scope of the invention may suggest themselves to those skilled in the art.

Claims

I claim:

1. A pad comprising:

an electrically conductive coil for conducting alternating electrical current;

an armature lying generally in a plane within said coil,

said armature comprising a plurality of strips of magnetic material, each of which overlaps the next and generally lies in a plane oblique to the plane of the armature;

and

a body of compliant material covering and in contact with each side of said armature between the coil and the armature, the compliant material being adherent to the sides of the armature,

whereby flow of alternating electrical current through the coil creates an alternating magnetic field surrounding said pad.

2. A pad according to claim 1 in which the compliant material is a foam.

3. A pad according to claim 1 in which the overlapped parts of adjacent strips are adherent to each other.

4. A pad according to claim 3 in which the adherence of the overlapped parts is caused by an adhesive which is not completely solidified.

5. A pad according to claim 1 in which the strips are flexible and have a length substantially greater than their width, and the overlapping parts of the strips comprise part of their width.

6. A pad according to claim 5 in which the overlapped parts of adjacent strips are adherent to each other.

7. A pad according to claim 1 in which the coil has sides parallel to the plane of the armature.

8. A pad according to claim 1 in which the outside of the coil is covered by a layer of compliant material.

9. A pad according to claim 8 in which the coil is adherent to the layer of compliant material.

10. A pad according to claim 5 in which the coil has sides parallel to the plane of the armature.

11. A pad according to claim 10 in which the overlapped parts of adjacent strips are adherent to each other.

12. A pad comprising:

an electrically conductive coil for conducting alternating electrical current;

an armature lying generally in a plane within said coil,

said armature comprising a plurality of strips of magnetic material, each of which overlaps the next and generally lies in a plane oblique to the plane of the armature, the overlapped parts of adjacent strips being adherent to one another; and

a body of compliant material covering and in contact with each side of said armature between the coil and the armature,

whereby the flow of alternating electrical current through the coil creates alternating magnetic field surrounding said pad.

13. A pad according to claim 12 in which the compliant material is a foam.

14. A pad according to claim 12 in which the strips are flexible and have a length substantially greater than their width, and the overlapping parts of the strips comprise part of their width.

15. A pad according to claim 12 in which the coil has sides parallel to the plane of the armature.

16. A pad according to claim 12 in which the outside of the coil is covered by a layer of compliant material.

17. A pad according to claim 16 in which the coil is adherent to the layer of compliant material.

18. A pad according to claim 12 in which the adherence of the overlapped parts is caused by an adhesive which is not completely solidified.