US2310844A - Electric knife with changeable points - Google Patents

Description

. Feb. 9, 1943. w. A. DRAEGER ELECTRIC KNIFE WITH CHANGEABLE POINT Filed April 9v, 1941 y Wbez raeger Patented Feb. 9, 1943 UNITED STATES ELECTRIC KNIFE WITH CHAN GEABLE POINTS Walter A. Draeger, Dawson, N. Dak.

Application April 9, 1941, Serial No. 387,732

1 Claim.

This invention relates to an improved construction of electric knife especially adapted for use in caponizing chickens, opening boils, abcesses and the like and for many other uses for which a surgical instrument of this type is adaptable.

More particularly, it is an aim of the invention to provide an electric knife so constructed that the wire point thereof may be readily removed and replaced so that a new point may be readily inserted should the old point burn off or otherwise become useless, and also to enable the use of points of different shapes.

Still another aim of the invention is to provide an electric knife wherein the point is made removable and replaceable so that a light gage wire point may be used for current of small voltage or a heavier gage point for use with a current of higher voltage.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawing, which illustrates a preferred embodiment of the invention, and wherein:

Figure 1 is a plan view of the electric knife, and

Figure 2 is an enlarged longitudinal sectional view, partly in elevation, of the holder and knife point thereof.

Referring more particularly to the drawing, wherein like reference characters designate like or corresponding parts throughout the different views, III designates generally the holder in its entirety and which includes an outer casing II, of electrical insulating material, and a core I2 which is disposed therein and which is likewise formed of a suitable electrical insulating material. As seen in Figure 2, the core I2 is provided with a longitudinal bore I3 which extends from end to end thereof and which opens outwardly of the end of the core I2, which forms the end of the holder I0. The core I2 is also provided with a longitudinal extending recess I4 which extends from adjacent the forward end I5 of the holder I0 and which opens outwardly of the opposite, rear end I6 thereof. Core I2 is provided with a longitudinal recess I1 which is preferably disposed substantially in alinement with the recess I4 and which opens outwardly of the forward end I5 and which extends inwardly to adjacent the inner end of the recess I4 but which is separated therefrom by a portion of the core I2.

An electrical conductor I8, preferably of copper, is xedly disposed in the bore I3 and ex- (Cl. 12S-303.14)

tends from end to end thereof and is provided with a longitudinal recess I9 which opens outwardly of the forward end I5 of the holder I0, and a longitudinal recess 20 which opens outwardly of the rear end I6. A conductor 2|, similar to the conductor I8, is disposed in the recess I4 and extends from end to end thereof and is provided with a longitudinal recess 22 which opens outwardly of its free end and of the end I6 of the holder I0. A conductor 23, of similar material, is disposed in the recess I1 and is provided with a longitudinal recess 24 which opens outwardly of its exposed end and of the holder end I5.

The casing II is provided with an opening 25 which communicates with a recess portion in the core I2, designated 25, and which in turn communicates with the inner end of the recess I4. A switch 21 of resilient conducting material, preferably copper covered spring steel, Lis provided with an inwardly offset end 28 which is secured in the recess 26 and in engagement with the inner end of the conductor 2l. The switch 2l also includes a portion 29, which is disposed obliquely to the portion 28 and the outer portion 30 and which projects obliquely through the opening 25. The portion 30 is disposed on the outer side of the casing II and is spaced Itherefrom and disposed substantially parallel thereto. The portion 30, at its free end, is provided with a knob 3| which projects from its inner side and which alines with an opening 32 in the casing lI and core I2 and which communicates with the recess I'I, adjacent the inner end thereof. The conductor 23 is provided with a concave portion 33 which opens into the opening 32 and which is adapted to receive and be engaged by the knob 3| when the portion 30 is pressed inwardly of the holder I0 to bridge the gap between the adjacent ends of the conductors 2l and 23.

Adjacent the end I5, the conductors I8 and 23, the core I2 and casing II, are recessed .to form outwardly opening inwardly converging recesses 34 in which are mounted metallic inserts 35, which are shaped to correspond to the recesses 34 and the outer sides of which conform to the curvature of the periphery of the holder I0, is best seen in Figure 1. The inserts 35 communicate with the recesses I9 and 24 and are provided with threaded openings 36 which extend therethrough for receiving set screws 3l.

The holder ID, previously described, forms the handle of the electric knife, comprising the invention, and which is provided with a point 38 formed from a strand of wire which is bent upon itself intermediate of its ends to provide the corresponding ends 39 which are adapted to be inserted into the recesses I9 and 24 and secured therein by tightening the set screws 31 for attaching one end 3S to the conductor I8 and the other end 39 .to the conductor 23. The exposed portion 4D, forming the intermediate portion of the strand of wire, and which projects from the end l5 of the holder or handle l0, constitutes the point or blade of the electric knife and may be of any desired shape.

A flexible, preferably rubber encased .electric cord 4I includes two conductor wires 42 which extend therethrough and which are insulated from one another in a Conventional manner. The conductor wires 42- have exposed ends Vor prongs 43 which project from one end of the cord 4| and which extend into and are suitablyv secured in the recesses 26 and 22 for vconnecting one of the ends or prongs 4.3 to the conductor I8 and the other end or prong 43 to the conductor 2|. The opposite ends of the conductor wires 42 are exposed andare provided with eyes 44 which are adapted to be connected to a suitj able source of electric current, as for example a dry cell battery. I

To operate the electric knifeythe holder H) is grasped similarly to a pencil and the switch 24 is pressed in to bridge the gap between the adjacent ends of the conductors 21 and 23 so that a circuit will be completed through the resistor wire 38 causing said wire to become red hot, at which time the instrument is in condition to be used. Should the point or blade 438 become white hot Ya heavier point is necessary and the screws 31 may be loosened and the point'38 removed and one of a heavier gage substituted. Likewise, should the point fail to turn red a point of `a lighter gage should be 'substituted or Va higher voltage current employed.

It will thus be apparent that points or blades 38 of diierent shapes and diierent resistances may be readily applied to or removed from the instrument to accommodate it to different operations and to use with currents of different voltage, as well as to enable a burnt oli` or broken point to be readily replaced.

Various modifications and changes are contemplated and may obviously be resorted to as only a preferred embodiment of the invention has been disclosed.

I claim as my invention:

An electric knife comprising a holder of insulating material provided with spaced longitudinally extending bores, electrical conductors Adisposed in the bores and opening outwardly of an end of the holder, said conductors having longitudinally extending recesses which open outwardly of corresponding ends thereof and which open outwardly of said end of the holder, said oonductors also having recesses'which communicate with the first mentioned recesses and which open laterally outwardly of the conductors, said holder having recesses which communicate with the last mentioned recesses of the conductors, inserts anchored in the last mentioned recesses of Vthe conductors and the recesses of the holder for retaining the conductors in position in the holder, said inserts and the recesses in which they are received being shaped to retain the inserts therein, a knife point formed from a strand of wire, the ends of the strand being disposed in the longitudinal recesses of the conductors, said inserts having threaded openings extending therethrough, and set screws engaging the threaded openings and releasably engaging the ends vof the strand for securely connecting the knife point to the conductors.

WALTER A. DRAEGER.

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