US2193702A - Electric medical appliance - Google Patents

Description

March 12, 1940. G. THORNTON-NORRIS ,7

ELECTRIC MEDICAL APPLIANCE Filed Nov. 29, 19 57 v 2 Sheets-Sheet 1 March 12, 1940. THORNTON-NORRIS 2,193,702

ELECTRIC MEDICAL APPLIANCE Filed NOV. 29. 1937 2 Sheets-Shet 2 Patented Mar. 12, 1940.

UNITED STATES PATENT OFFICE ELECTRIC MEDICAL APPLIANCE Application November 29, 1937, Serial No. 177,085 In Great Britain November 30, 1936 10 Claims.

This invention relates to electric medical appliances adapted to apply electric current to patients, for diagnostic or for curative purposes and it has reference, in particular, to appliances of this kind wherein at least one coil or solenoid in which the electric current is generated is furnished with a movable core of magnetic material, which core, when the appliance is operating, is moved rhythmically by automatic driving means and produces a corresponding change of the said current, this change being known as surging. As is Well known, the surged current, when administered to a patient, will, if sufiiciently intense, produce corresponding contractions and extensions in the muscles affected.

The rate of surging and the duration of each surge of current are regulated by the frequency with which the movable magnetic core or surger is introduced into and withdrawn from the coil, while the current intensity can be varied by introducing the surger to a greater or less extent.

It is an object of the present invention to provide an electric medical appliance of the kind referred to wherein means are provided for altering the characteristic form of the surged output current and thereby controlling the muscular reactions of the patient under treatment.

A further object is to provide an apparatus of this kind which, when set in operation, will maintain with considerable accuracy any desired periodicity as well as any desired intensity of surging.

A still further object is to afford fine regulation of the intensity of the current applied to the patient.

Another object of the invention is to provide improved means for varying the rate and periodicity of surging within the useful limits of practice and a more specific object is to provide for withdrawing the surger froml the coil faster than it is introduced thereinto or vice versa.

Yet another object of the invention is to provide manually operable means for finely graduated adjustment of the current generated in the coil for any given position of the surger core. This last mentioned means may substitute but is preferably used to supplement the well known layer switch the contacts of which are severally connected to various tapping points in the winding of the coil. Conveniently the said means may take the form of a variable resistance in circuit with the coil windings: preferably in the primary or energising circuit of the coil.

In the accompanying drawings which show one embodiment of the invention;

Fig. 1 is a plan View of the control panel of an electric medical appliance of the kind referred to and of a box-like casing for the appliance, the said casing being shown with a cover thrown open to expose the panel.

Fig. 2 shows in frontal elevation, the panel and. the various members mounted thereon, some directly and others indirectly.

Fig. 3 is a sectional plan View, the section be ing taken on line III-III of Fig. 2.

' Fig. 4 is a circuit diagram.

Referring firstly, to Fig. l, the control panel I of the appliance is mounted, as is usual, in a box-like casing 2 with a. lid or cover 3, hinged to it, as at 4. The panel carries on its upper side, the usual trembler 5, mounted on a post 35, the contact screw 6 adjustable in a post 36, the actuating magnet I, with iron core 31, for driving the trembler, the so-called patient terminals 8, to which various electrodes or applicators can be connected, and manual controls 9, l and H, hereinafter again referred to. The aforesaid trembler is provided with an armature 33 having a rod 34 carrying an adjustable damping Weight 38.

Part of the hollow cover 3 may be. partitioned off, as by a hinged partition 12 and/or said cover may be furnished with one or more clip devices, such as l3: in these ways accommodation is provided for storing electrodes, applicators and flexible connections (including mains connections, as hereinafter referred to) when not in use.

Reference l4 (Figs. 2 and 3) designates a subpanel, supported by brackets Hi from the main or exposed panel I. The induction coil or current producing device comprises, in the example shown, two coil elements l6 arranged with their geometrical axes parallel and each furnished with a slidable iron core i l, constituting a surger. The two surgers are coupled together by a yokepiece l8 carried slidably on a rod [9 which is fixed at 120 and at 52 so that its axis is parallel to the axes of the coil elements it and their surgers Ill. The yoke I8 also carries a slotted lug 2|, the purpose of which will hereinafter appear.

A suitable operative drive for said surgers is provided by an electric motor 22 mounted in this instance on the sub-panel M. As shown, said motor is below the said sub-panel and its shaft 23 projects through said panel and. has fixed to it a toothed pinion 24. The latter gears with a spur wheel 25 which is mounted rotatably on a stud 26 and is furnished with a crank pin 21. This crank pin, when the wheel 25 is rotated (by motor 22, driving through pinion 24) Works to and fro along a slot 28 in a lever 29 pivoted at 30 and having, at its free end, a pin 31, adapted to work in a slot 32 in the lug 2!. It will be perceived (see Fig. 3) that oscillation of the lever 29 by the crank pin 21 causes the yoke 18 to slide on the rod l9, thereby reciprocating the surgers ll so that the latter move into and out of the coil elements l6. Said crank pin 27, as it is moved around in a circular path, acts on the oscillating lever 29 with an effect rendering it a continually changing lever arm, so that, according to the direction of rotation of the drive, either the introducing strokeor the withdrawal stroke of the surgers relatively to the coil elements can be made the more rapid. The motor 22 may be made reversible with the aid of a. simple reversing switch (not shown), or reversible transmission gearing (also not shown)-may be interposed between the motor and the surgers.

The periodicity of surging as well as the mean linear speed of movement of the surgers can be varied by varying the speed of the motor 22 with the aid of an adjustable mechanical governor, as usually employed for controlling the speed of gramophone motors. A speed control shaft is indicated at 39 (Fig. 3). This shaft is rotatable through a limited arc by means of a slotted arm lll affixed to that end thereof which protrudes through and above the sub-panel i l. The knob l8 (Figs. 1 and 2) controls a spindle ii on which are fixed a cam 42 and an arm 43, the latter carrying a stud M engaging slidably with the slot 45 of the aforesaid arm 40 sothat turn of the spindle (by said knob) Will swing the interlinked arms, as indicated by the dotted line positionings thereof, to consequently turn or rotate the shaft 39 within its arc limits determined by the length of said arms. In this arrangement of course the spindle. H and the shaft 39 are rotatable in opposite directions. A switch 45 provides for opening and closing the operative drive motor circuit. The aforementioned cam 42 is adapted to operate this switch. Said cam has a flat surface portion ll which, in the position shown in Fig. 3, allows the said switch to remain open, but any part of the remaining arcuate surface 48 thereof will hold the switch closed when the said cam is turned to an appropriate position by means or" the knob l and spindle All. It will readily be seen that the arcuate portion 48 of the cam is operative over a considerable angular range of rotation to keep the switch closed. Within this range the linkage provided by the interconnected levers 43 and it is operable to adjust the shaft 39 for varying degrees of motor speed adjustment by acting on the governor setting. The arrangement illustrated is such that initial clockwise ro tation of the. cam 42 closes the switch 46, while further movement in the same direction gradually reduces the speed to which the motor is governed and, therefore, reduces the surging speed. The motor is stopped by rotating the cam 42 counter-clockwise, back to the position shown in Fig. 3. Whereas, with this arrangement, motor starting, stopping and speed regulation are under the control of one and the same knob ill, it will be obvious that the starting and stopping switch may be actuated by a control which is independent of the control used for varying the speed. Purely electrical'means of controlling the speed of the surger actuating motor in apparatus of the kind referred to has previously been suggested but in most cases I prefer to use a mechanical control, as described, acting on a speed governor with a frictional braking action as in ordinary gramophone motors.

A preferred arrangement of the electrical circuits is shown in Fig. 4. In this diagrammatic showing the surger coils Ill are depicted as comprising primary windings- P (in series with the trembler magnet coil 7, resistance battery 52 and trembler contacts 5, 5) and tapped secondary windings S, the tapping points being several- 'ly connected to contacts of the layer switch 50.

The coil circuits may be and preferably are quite separate from the circuit of the surger actuating motor. The last named circuit, being quite conventional, is, therefore, not included in Fig. 4. Ordinarily the coil is battery driven, whereas the motor preferably takes power from the mains, as, for instance, through suitable mains-connecting terminals 49 provided on the main panel I of the instrument. These terminals are shown as sockets adapted to receive a plug associated with a flexible connector (not shown) which connector, when not in use, can be coiled up and lodged under the clip l3. A battery, feeding the primary coil circuit, can be housed in the casing 2.

The said panel I also carries the usual so -called layer switch 56 (Figs. 2 and 4) for varying the number of turns of coil windings included in the secondary or patient circuit, the knob 9 serving for adjustment of this switch. The fine or Vernier manual adjustment which constitutes a further feature of the invention here takes the form of a variable resistance 5!, included in the primary or battery circuit of the coil (see Fig. l) to vary the strength of the primary current derived from the battery 53.

The resistance fail is of a kind adapted for fine regulation and such regulation is effected by means of the knob ii (Fig. 1). It is to be understood that for every position of the layer switch 5! a long range of finely variable adjustment of current strength can be obtained with the additional control 5!. thermore this additional and fine control permits of adjusting primary current so as to obtain optimum action of the trembler blade 5 which, co-acting with the contact 6, makes and breaks the primary coil circuit in the usual manner. Regular, that is to say, non-erratic, trembler action is generally preferred and is favoured by careful adjustment of the primary current strength, as described. This additional control means can easily be arranged so that the primary coil circuit is broken in one position. of the manipulating knob H and, finally, the latter can, in. case of need, be worked periodically by hand to produce a surging effect independently of the movable core already referred to and of the motor for driving the said core. This latter possibility is extremely useful in event of failure of the motor or of its gearing to the movable core member or again, in cases where power for operating an electric. motor is not available. Naturally, nonelectric motors, such as clockwork or fluid driven motors may be used for operating the surger core, the motor starting and speed regulating control being appropriately modified as and Where necessary.

In particular, in the case of a non-electric motor, a mechanical lock (for clockwork) or a valve for fluid driven motors) would replace the switch M5.

The arrangements described (which are portable and require no liquids) permit the current to be exactly regulated, as regards both intensity and rate of surging, to the particular patient or patients under treatment. This can be done safely, particularly with the aid of the fine or Vernier control, while the patient is actually in the secondary circuit and when the required conditions have once been established they can be maintained indefinitely for as long as the treatment is required to continue, so that the operator whose duty it is to administer the said treatment is not compelled to watch its progress or perform any continuous manipulation but can give attention to other matters.

On the other hand, it is sometimes helpful for the operator to have visual indication of the surger movement or of the position of the surger at any given moment (other than such indication as is provided by the muscular reactions of the patient or patients under treatment). A mechanical indicator such as a pointer or its equivalent, driven directly by the core structure or by some part of the transmission mechanism may be used for this purpose, such pointer preferably working in conjunction with a scale on the panel. Alternatively the indicator may be arranged to signalise only the fully inserted position ofthe cores, this being the position in which the aforementioned manually controlled surging by means of the Vernier control is most effective. Both limiting positions of the reciprocating core structure may be thus indicated. Luminous indicating means (i. e. an electric lamp switched by the moving surger mechanism.) may, of course be employed.

What I claim is:

1. In an electric medical appliance, a coil, means for generating an electric current in said coil, means for delivering the current so generated, a magnetic body movable in. relation to said coil to vary the strength of the current generated therein, a motor operatively connected to said movable magnetic body to actuate the same and thereby to surge the generated current and manually operable adjustable speed governing means co-actable mechanically with said motor for therethrough varying the rate and periodicity of the surging while the device is in operation.

2. In an electric medical appliance: a coil, means for generating an electric current in said coil, means for delivering the current so generated, a magnetic body movable in relation to said coil to vary the strength of the current generated therein, a motor and transmission mechanism operatively connecting said motor to said movable magnetic body to move the latter to and from said coil, said transmission mechanism being organised to move said body towardssaid coil at a mean speed difiering from the mean speed at which it moves said body away from said coil.

3. The device of claim 2, characterised by means operable at will to render the mean speed of approximation of the movable magnetic body to the coil greater than or less than the mean speed of retraction of said body from said coil.

4. The device of claim 2 including means acting mechanically on said motor to control the speed thereof and means including interlinking swing arms operatively connected between said speed control means and separate manually turnable means for adjusting said speed controlling means and maintaining the same in the adjusted position.

5. In an electric medical appliance; a coil, means for generating an electric current in said coil, means for delivering the current so generated, a surger for the generated current, said surger comprising a magnetic core reciprocable into and out of said coil, power operated rotary driving means, transmission means including a plurality of rotary elements operatively interposed between said driving means and said surger and means for reversing the direction of rotation of the final rotary element of said transmission means, the latter coacting with a transmission element which, according to the direction of rotation of said final rotary element, determines whether the mean speed of withdrawal of the surger from the coil is greater or less than the mean speed of introduction, of said surger into said coil.

6. In an electric medical appliance; a coil, means for generating an electric current in said coil, means for delivering the current so generated, a surger for the generated current, said surger comprising a magnetic core reciprocable into and out of said coil, a motor operatively associated with said surger to reciprocate the latter and control means for said motor, said control means being adapted upon initial movement from a terminal position, to start said motor and, upon further movement, to adjust a mechanical governor controlling the speed of said motor.

'7. A device according to claim 6, characterised by an electric driving motor, a starting switch for said motor and means such as a cam, actuated by the control means and operative to close said switch upon initial movement of said control means.

8. In an electric medical appliance, a sectionalized coil having a primary circuit including energising means and manually operable means for adjusting the degree of energisation and a secondary circuit associated with means for including therein a variable number of sections of the coil, for delivery therefrom of secondary current and automatically operating means for surging the delivered secondary current.

9. A device according to claim 8, and including variable means for adjusting the rate and periodicity of surging of the delivered secondary current.

10. A device according to claim 8, including means for varying the characteristic form of the surged secondary current.

GEORGE THORNTON-NORRIS.

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