Apparatus for applying electrical currents to the body.

  • Smart, Morton
Date:
1925
Catalogue details

Licence: Public Domain Mark

Credit: Apparatus for applying electrical currents to the body. Source: Wellcome Collection.

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    Dpcnbaar gemaakt , a 11Q5 Bibliotheek ur. lnd. Eigendom 2 4 Jill, 1925 PATENT SPECIFICATION Application Date : June 14, 1924, No. 14,467 24. Complete Accepted: June 18, 1925. 235,388 COMPLETE SPECIFICATION. Apparatus for Applying Electrical Currents to the Body. I, Morton Smart, D.S.O., M.D., of 40, Park Lane, London, W. 1, a British subject, do hereby declare the nature of this invention and in what manner the 5 same is to be performed, to be particu¬ larly described and ascertained in and by the following statement:— This invention relates to electro medical apparatus and has for its object 10 to provide apparatus capable of produc¬ ing- painless graduated muscular con¬ traction under complete control of the operator. It is well known that the secondary ;5 current produced by an ordinary induc¬ tion coil with the usual type of make and break, even when controlled by a laminated iron core, produces spasmodic movement of the muscles when applied to 20 the human body, and is therefore in¬ capable of use for fractures and unad- visible for most other muscular remedial measures. I have discovered however that it is 25 possible to produce painless graduated muscular contraction under complete con¬ trol of the operator by means of alter¬ nating current of a special form de¬ scribed hereinafter, and mv invention 30 consists in the hereinafter described apparatus for producing this alternating current comprising an induction coil having a variable inductive coupling between the primary and secondary qir- 35 cuits and 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 interruption of the primary is substan- 40 tially equal to the average rate of growth thereof. Whilst not attempting to explain the reasons underlying the physiological result obtained, it has been found that 45 the particular form of current produced coupled with a large range of control m [Price 1 /-] the secondary circuit imparts a muscular stimulation of such a nature as cannot otherwise be obtained, and for the pur¬ pose of identification oscillograph curves 50 illustrating the changes in potential in the secondary winding of the inductance form part of the drawings hereinafter described. Reference will now be made to the 55 accompanying drawings which illustrate an apparatus constructed according to the invention and in which:— Figure 1 is a diagram showing the dis¬ position of the elements constituting the 60 apparatus and the electrical connections. Figure 2 is a longitudinal sectional elevation of the mercury interrupter. Figure 3 is an oscillograph diagram illustrating the changes in potential in 65 the secondary winding of the inductance, and Figure 4 is a similar diagram taken at slower speed and comparing the current flow in the primary winding and the 70 change of potential in the secondary winding. In the drawings Figure 1 indicates a base plate upon which are mounted an electric motor indicated diagrammati- 75 cally at 2, and a rotary circuit inter¬ rupter similar indicated at 3 which is rotated by the motor. The motor 2 is supplied with current from supply mains connected to terminals 4 and in order to 80 control the speed of the motor a series of resistance plates 5 is interposed in the motor circuit which also includes a rheostat (not shown) connected to ter¬ minals 6 and a five position switch 7 by 85 adjustment of which the number of resist¬ ance plates 5 in circuit is controlled. Alternatively, a rheostat of suitable resistance may be used and the resistance plates and five point switch dispensed 90 with. The primary winding of an induct¬ ance coil is indicated at 8, and this coil