US1827045A - Electromedical apparatus - Google Patents

Description

Oct. 13, 1931 v M. SMART 1,827,045

ELECTHOMEDICAL APPARATUS Filed Jan. 51, 1930 5 Sheets-Sheet 1 Z ,POWER LJNEs v I 1- 2 55+ i459 TO PATIENT MORTON 5MHE7;

Oct. 13, 1931. M. SMART ELECTROMEDICAL APPARATUS Filed Jan. 31. 1950 '3 Sheets-Sheet 2 1520676507: y ffo/ero/v 5/7457;

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0a. 13, 1931. M. S MART ELECTROMEDICAL APPARATUS Filed Jan, 31, 1930 3 Sheets- Sheet 3 I NORTON 5/7HE7', m 4/$/?/0/Wey.

Patented Oct. 13, 1931 PATENT OFFICE I MORTON SMART, OF LONDON, ENGLAND ELEGIROMEDICAL APPARATUS Application filed January 31, 1930. Serial No. 425,030.

This invention relates to electro medical apparatus and has for its object the provision of apparatus capable of producing painless graduated muscular contraction under complete control of the operator.

It is well known that the secondary current produced by an ordinary-inductioncoil with the usual type of make and break, produces spasmodic movement of the muscles when apm plied to the human body, and is therefore incapable of use for fractures and unadvisable for most other muscular remedial measures.

The present invention has for its object the provision of an apparatus capable of pro ducmg painless graduated muscular contraction under complete control of the operator by means of alternating current of a special form hereinafter described.

The apparatus of this invention consists broadly of an induction coil having a variable inductive coupling between the primary and secondary circuits and is provided with a make and break device which breaks the primary circuit gradually so that the average rate of collapse of the field due to each inter ruption of the primary is substantially equal to the average rate of growth thereof.

In the drawings:

Figure 1 is a diagrammatic view of the apparatus.

Figure 2 is a plan of the coil of the apparatus, partly in section.

Figure 3 is a sectional view taken on the line III--III of Figure 2.

Figure 4 is a similar view taken on the line IVIV of Figure 2.

Figure 5 is a sectional elevation of the interrupter.

Figure 6 is a sectional View through the interrupter taken on the line VI-VI of F igure 5.

Referring more particularly to the drawings the numeral 2 designates a base plate on which is .mounted a motor 3 coupled by a flexible insulated coupling 4 to a mercury interrupter 5. i A sliding rheostat 6 is mount ed on the base 2 and is connected in the motor circuit to control the speed of the motor.

A panel plate 8 carries an inductance coil 9 comprising a primary winding 10, a secondary winding 12, and a sliding core 13. The primary winding 10 consists of double cotton covered copper wire of No. 18 standard wire gage, equivalent'to .048 inch diameter of bare conductor having a resistance of 13.3 ohms per one thousand yards. lVhen wound on the bobbin or spool 14 the wire should give 17.2 turns per inch. Tapping wires 10 of double silk covered wire of No. 23 standard Wire gage, equivalent to .024 inch diameter,- are brought out from the ends of each layer and taken to the soldering tabs 15 under the binding screws 16 on the ends of the bobbin or spool flanges or ends 17. The ends of the bobbin or spool are slotted to receive the tapping wires, as at 18.

The primary winding 10 is covered by a completel layer of insula-tedsilk tape 10".

The secondary winding 12 consists of double silk covered copper wire of No. 30 standard Wire gage, equivalent to .0124 inch diamcter of bare conductor having a resistance of 199.15 ohms per one thousand yards. \Vhen wound, the wire should give 67.1 turns per inch. The end of each layer of the secondary winding 12 is looped up to form taps 12 and connected to soldering tabs 15 under binding screws 16 on the ends 17 of the spool 14. Each layer of the secondary winding 12 is separated by a layer of insulating tape 20 and the complete coil is finished off by covering the secondary winding with a layer of tape 21 cemented in place.

The binding screws 16, to which the taps 10 and 12 are connected, are connected by suitable leads to contacts 23 of contact switches having sliding contacts 24.

The sliding core 13 of the coil 9 is composed of laminated wire mounted in an insulating tube 81 having a handle 82 and adapted to be inserted and withdrawn 'from the coil to vary thesecon'dary or induced curof mercu VII 30. The mercury is adapted to be filled into the chamber through a filler member 31 mounted in the end plate 27 and normally closed by a cap 32.

The end plate 25 is provided. with a central aperture 33 in which an insulating bushing 34 of bakelite or the like is mounted. The bushing 34 is provided withl a flange 35 which abuts the outer face of the plate 25, and with a tubular nose portion 36 which projects within the mercury chamber and serves to support and prevent whipping of a contact spindle 38. A metallic sleeve 39 is mounted in the bushing 34 and projects outwardly therefrom to form a support for the spindle 38. The sleeve 39 is provided with a flange 40 which overlies the flange 35 on the bushing and is secured in position by screws 41.

Suitable anti-friction bearings 42 are mounted in the sleeve 39 and the spindle 38 is journaled therein.

An insulating sleeve 43 is fitted on the spindle 38 and extends from adjacent the forward end of the spindle rearwardly into the sleeve 39. The forward end of the spindle 38 is squared, as at 44, and has a double ended contact blade 45 mounted thereon. A short thimble 46 of insulating material is fitted over the end of the spindle and a nut 47 is threaded on the spindle and serves to force the thimble 46 against the contact blade 45 and to thereby clamp the blade in position between the thimble 46 and sleeve 43.

A suitable splash plate or disk 49 is nrounted in the mercury chamber in spaced relation with the end plate 25 and serves to narrow down the mercury chamber and also to battle the waves or splashes of mercury so as to prevent the mercury seeping through the oint formed between the bushing 34 and plate 25.

The splash plate or disk 49 is composed of insulating material and is provided with a peripheral rubber sealing ring 50 which forms a sealing connection with the glass cylinder 29 forming the sides of the mercury chamber.

The end plate 27 is provided with a centrally arranged aperture in which a shaft 51 is journaled having an arm 52 secured to its inner end carrying a block 53 of wood or similar non-conducting material which is adapted to be inserted into or withdrawn from the mercury by rotation of the shaft 51 to raise or lower the level of the mercury. The shaft 51 is provided with a worm-wheel 54, which is keyed thereto, and is meshed with a worm 55 on a shaft 56 extending out beyond one side of the apparatus and provided with a hand wheel 57 by which it may be manually rotated to operate the shaft 51 and block 53.

The part of the flexible coupling 4 mounted 011 the spindle 38 includes a contact drum 85 through which the current from the interrupter 5 is delivered to a brush contact 86. The motor 3 receives its power from the ordinary house lines 58 and 59. The line 58 has the rheostat 6 connected in series therewith and is connected to one pole of the motor. The line 59 is connected to a switch 60 and a line 61 extends from the switch 60 to the other pole of the motor. In operation, the speed of the motor, and consequently the speed of the mercury interrupter, is governed by the operation of the rheostat 6.

The induced current applied to the patient is provided from a battery 62 which has one pole connected by a line 62 to the base 26 of the interrupter which is electrically connected with the mercury. The other pole of the battery is connectedb-y a line 63 and switches 64, 65, and 66 to the sliding contact arm 24 of the primary coil tap switch. The switch 64 is a supplemental switch used as an emergency circuit breaker. The switches 65 and 66 are adapted to be operated to open and close the circuit to the primary coil during regular operation. The inner end of the primary coil is connected by a line 68 with the brush contact 86 which receives the interrupted or alternating current from the interrupter 5.

The induced current from the secondary winding passes through lines 70 and 71 to any suitable form of applicator. The line 70 leads from the inner end of the secondary winding while the line 71 is connected to the sliding contact arm 24 of the secondary tap switch.

In operation, therheostat 6 is preferably adjusted so that the motor 3 will operate the spindle 38 of the interrupter 5 at 1800 revolutions per minute, thereby causing the blade 45 to contact with the mercury 3600 times per minute and the effect is that as the member or blade 45 strikes the mercury, making sudden and complete contact, a magnetic field is built up with comparative rapidity in the inductance causing the potential across the secondary winding to rise. During that; portion of the period of contact between the mercury and the blade 45, while the flow of primary current and the intensity of magnetic field is practically constant, the induced potential begins to decrease. Owing, however, to the inductance or electrical inertia of the coil, the fall of the induced potential takes an appreciable time, and before it reaches zero value, the blade 45 leaves the mercury and interrupts the primary current with the result that the magnetic field collapses, the induced potential falls to zero, and owing to the collapsing field, changes its sign and again increases until the final and complete extinction of the magnetic field allows the induced potential to fall to and remain at zero value until a new cycle begins.

As the blade .45 leaves the mercury, the cessation of current flow is not instantaneous owing largely to the fact that the blade carries with it a certain amount of mercury or mercury vapor which is drawn out and burns as a momentary mercury arc, thereby introducing a gradually increasing resistance into the primary circuit and preventing a sudden collapse of the magnetic field. This retarding effect on the collapse of the magnetic field prevents the excessive rise of induced potential which would otherwise take place in the secondary circuit.

The form of the alternating current produced is of great importance. The amplitude of the alternations of the current is a variable quantity dependent, among other things, upon the initial voltage across the primary. coil and the amount of magnetic coupling between the windings of the coil,.

but the form of the current is determined by the time intervals between make and break in the primary circuit, the nature of the interrupter,'the self induction of the coil, and other physical constants of the instrument.

The regulation of the induced secondary current, as applied to the muscles of the patient both in tlIIlSG and intensity, is effected and controlled by the insertion or withdrawal of the movable laminated core of the coil. The operator is enabled to cause alternate painless contraction and relaxation of the muscle or group of muscles, and the type of contraction produced so closely stimulates the physiological contraction of a muscle, that the result is indistinguishable from a normal voluntary contraction.

The contraction produced is under the absolute control of the operator, and the rise and fall of the stimulus can be so accurately graduated that, starting from zero, it may be gradually increased 'to the maximum contraction which the muscle acted -upon is capable of without damage, and the muscle then allowed to relax just as gradually, or, if necessary, it may be held in a state of contraction.

The contraction thus produced is in no way a local spasm of part 0 the muscle as is produced by the usual medical faradic coil, but

is a wave contraction of the entire length ofthe muscle. A single muscle, or a whole group of muscles, may be contracted and relaxed in thisway. A healthy group'of muscles, when acted upon by the a paratus of this invention, can thus be ma e to contract and relax rhythmically, so as to cause painless reproduction of the full movements of the joint 4 upon which the particular group acts.

I claim: 1. In an electro medical apparatus for pro 'ducing alternating current adapted to cause muscular contraction on a patient under com plete control of the operator, an inductance 0011, said 0011 comprising a spool composed of of Number 18 gage, said winding having taps leading from each layer thereof to contacts on the ends of said spool, a layer of insulating tape mounted over said primary winding, a secondary winding wrapped on said layer of insulating tape and comprising a plurality of layers of double silk covered copper wire of Number 30 gage, each layer of said secondary winding being separated by a layer of insulating tape, said seconda winding having a plurality of taps forme by loops of selected ones of the layers of said secondary windmg, said taps being connected to contacts on the ends of said spool, the one end of said primary winding being connected to an input contact on one end of said spool, and the one end of said secondary winding being connected to an output contact on the other end. of said spool, a core tube formed of insulating material slidably mounted in said spool, a laminated core mounted in said tube and movable therewith, said core being adapted by its insertion into and withdrawal from the 0011 to regulate the induced secondary current.

2. In an electro medical apparatus for producing alternating current adapted to cause muscular contraction on a patient, an nducance coil, and an interrupter 1n theprimary circuit of said coil, said interrupter comprising a cylindrical mercury chamber having lass side walls and metal end walls, a shaft ournaled in the rear end wall and insulated therefrom, a double end contact blade mounted on 'the inner end of said shaft andadapted to make and break contact with the mercury in saidchamber when said shaft is rotated, an insulating sleeve surrounding the inner portion of said shaft, and an insulating support for the inner end of said shaft, a mercury level modifier comprising a block of nonconducting material mounted in said chamber and adapted to be moved into and out of the mercury to raise and lower the mercury level.

In testimony whereof, I have hereunto set my hand.

MORTON SMART, M. D. Cu. B.

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