Switching device for electro-surgical instruments

Abstract

A pressure-sensitive switch which finds useful application with electro-surgical instruments includes a first electric conductor leaf having spaced axially aligned electric insulating sleeves of a heat-shrinkable material defining an actuation gap therebetween. The insulating sleeves maintain a predetermined spacing between the first conductor leaf and a second electric conductor leaf which is disposed in adjacent parallel relation to the first conductor leaf. Electrical leads are attached to each conductor leaf and the entire switch is encased within a flexible heat-shrinkable material that forms a seal around the switch and allows pressure to be applied against one of the conductor leaves in the actuating gap between the insulating sleeves to move the leaves into electrical engagement. The switch is specifically adaptable for use with electro-surgical forceps wherein the switch can be mounted either for automatic or selected manual operation and for use with electro-surgical pencils wherein a modification of the switch includes double actuating gaps whereby selected electrical currents can be supplied to an electrode probe received in the pencil to permit cutting and coagulation with the same electro-surgical instrument.

Description

The present invention relates generally to pressure-sensitive switches and more particularly to a pressure-sensitive switch adapted for use with electro-surgical instruments.

Numerous pressure-sensitive switches having flexible outer rubber casings have been contrived for operating electrical devices. Examples of such switches are disclosed in U.S. Pat. No. 1,911,444 issued to C. D. Fator; U.S. Pat. No. 1,296,088 issued to B. J. Jones; U.S. Pat. No. 3,541,488 issued to C. S. Odson; and U.S. Pat. No. 2,138,549 issued to O. J. LaBell. The switches disclosed in the aforementioned patents were developed for various uses and assume numerous designs dependent upon the use for which they were intended. In general, however, it has been found that switches now commercially available vary drastically in complexity and sensitivity depending upon their intended use.

More recently, pressure-sensitive switches have been incorporated into electro-surgical instruments to avoid disadvantages which were previously inherent in electro-surgical systems wherein switches for operation of the electro-surgical instruments were operated by a foot pedal beneath the operation table. According to previous procedures, it was necessary for the surgeon to contact the tissue to be cauterized or cut and then actuate a foot pedal switch. Not only was this distracting to the surgeon but increased the danger of accidently cauterizing or cutting adjacent tissue.

Several hand-operated electro-surgical instruments have been developed having an electrical switch built into the instrument so as to alleviate the problems which accompanied the previously described foot-operated switch. Examples of these instruments can be found in U.S. Pat. No. 2,894,512 issued to R. Tapper and U.S. Pat. No. 3,494, 363 issued to R. Jackson. It will be readily apparent that the electro-surgical instruments disclosed in these patents are an improvement over the foot-operated electro-surgical systems previously employed; however, as will be appreciated from the description of the present invention hereinafter, the prior art electro-surgical instruments are not entirely satisfactory for several reasons.

The pressure-sensitive switch of the present invention is a simple and highly reliable device which is long-lasting and dependable in operation. The simplicity and highly reliable nature of the switch makes it especially suitable for use with electro-surgical instruments in selectively controlling electrical energy supplied to the instruments. In its preferred form, the switch of the present invention includes a first electrically conductive element having spaced and axially aligned electric insulating sleeves defining an actuation gap therebetween and a second electrically conductive element spaced from the first conductive element. A heat-shrinkable casing surrounds both conducting elements and the insulating sleeves to enclose the switch and form an outer protective seal so that pressure applied through the rubber casing in the vicinity of the actuation gap will cause the conductive elements to move into electrical engagement to close the switch.

The switch of the present invention is principally intended for use in combination with hand-operated electro-surgical instruments, such as, electro-surgical forceps or electro-surgical pencils, whereby the surgeon need merely apply fingertip pressure to the switch for operation of the instrument. An important feature of the switch is that it can be easily incorporated onto existing electro-surgical instruments for operation thereof in obtaining the desired electrical potential on the operating tips of the instrument. The simplicity and compactness of the switch make it readily adaptable for attachment to electro-surgical instruments merely by positioning the conductive elements adjacent the body of the electro-surgical instrument and applying the heat-shrinkable flexible rubber casing around the switching elements and the associated body portion of the instrument so that the switch is positively secured to the instrument. It will be readily appreciated from the detailed description hereinafter set forth that in the case of electro-surgical forceps wherein spaced arms are mounted for pivotal movement toward and away from each other to grasp skin tissue, the switch can be mounted between the arms of the forceps whereby when the arms are moved toward each other a pushbutton actuator on one arm will move into the actuation gap of the switch to close the switch when increased pressure is applied in pinching the skin tissue between the arms of the instrument. Alternatively, the switch can be similarly affixed to the outer surface of one of the forceps arms so that the switch can be closed by finger pressure of the surgeon when desired.

A modified form of switch has been devised for electro-surgical pencils which are used both for cutting and coagulation purposes, depending upon the form of the electricity transmitted to an electrode probe on the pencil. In the modified form, spaced axially aligned elctrically conductive actuating elements having spaced electric insulating sleeves therearound define two actuation gaps so that either actuating element can be moved into engagement with a common electrically conductive contact element lying contiguous to the insulating sleeves. The switching elements are encased in a flexible rubber heat-shrinkable material so that pressure applied in either one of the actuation gaps will effect transmittal of a preselected frequency of electrical energy from an electrical source to the electrode probe.

Accordingly, it is an object of the present invention to provide a pressure-sensitive switch having spaced electrically conductive elements, one of which includes axially aligned and spaced electric insulating sleeves defining an actuation gap whereby pressure applied to one of the conductive elements will move the elements into electrical engagement in the actuation gap.

It is another object of the present invention to provide a pressure-sensitive switch having spaced electrically conductive elements disposed for movement into and out of engagement with each other and having a heat-shrinkable flexible covering to establish an environmental seal about the conductive elements.

It is another object of the present invention to provide a pressure-sensitive switch adapted for ready attachment to electro-surgical instruments to facilitate easy operation of the instruments.

It is another object of the present invention to provide an electro-surgical instrument having a simplified pressure-sensitive switch attached thereto either for automatic or selected manual operation by a surgeon.

It is still another object of the present invention to provide a pressure-sensitive switch for use with electro-surgical instruments having an electrically conductive actuation element covered by spaced insulating sleeves and a contact element adjacent the insulating sleeves whereby the actuation and contact elements can be moved into engagement to cause electrical energy to be transmitted to the operating end of the electro-surgical instrument.

Other objects, advantages and capabilities of the present invention will become more apparent as the description proceeds taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal vertical section taken through one embodiment of the pressure-sensitive switch of the present invention.

FIG. 2 is a transverse section taken along line 2--2 of FIG. 1;

FIG. 3 is a longitudinal section taken through electro-surgical forceps incorporating the switch of FIG. 1;

FIG. 4 is a longitudinal section of the forceps shown in FIG. 3 with an alternative arrangement of the switch of FIG. 1;

FIG. 5 is a longitudinal vertical section taken through a second embodiment of the switch of the present invention;

FIG. 6 is a perspective view of an electro-surgical pencil incorporating an alternative arrangement of the switch of FIG. 5;

FIG. 7 is a longitudinal vertical section taken through the pencil of FIG. 6;

FIG. 8 is a diagrammatic longitudinal horizontal section of the pencil of FIG. 6 showing the electrical wiring connections; and

FIG. 9 is a longitudinal section view of another alternate embodiment for an electro-surgical pencil.

Referring to the drawings, there is shown in FIG. 1 a preferred embodiment of a pressure-sensitive switch 10 of the present invention which broadly includes a switch actuation element or electric conductor leaf 12, a switch contact element or second electric conductor leaf 14, axially spaced electric insulating sleeves 16 surrounding the actuation element 12, and a casing 18 surrounding the switching elements and the insulating sleeves.

In the preferred form, the electric actuation element 12 and the electric contact element 14 are flatened elongated resilient strips of an electrically conductive material such as beryllium copper or a similar metal with good corrosion resistance, excellent electrical conductivity, and high fatigue strength. At corresponding ends of the actuation and contact elements, electrical lead wires 20 and 22 are secured at 24 and 26, respectively, to connect the elements 12 and 14 to an electrical supply, not shown. The insulating sleeves 16 around the actuation element 12 are axially or longitudinally spaced to define an actuation gap 28 therebetween. preferably, the insulating sleeves are composed of a heat-shrinkable material such as a material sold under the trademark "Kynar" by Raychem Corporation of Menlo Park, Calif. The heat-shrinkable material preferably used is characterized by having a heat shrink capability of 50 percent at temperatures above 175.degree.C, is an extremely tough, semi-rigid material having high strength with outstanding resistance to abrasion and cut-through and will withstand steam autoclaving (275.degree.F steam under pressure). Moreover, the material does not split when shrunk over sharp or irregularly shaped objects and remains flexible in its shrunken condition. Accordingly, the material provides an effective seal around metallic materials to resist chemical or solvent attacks and is sufficiently resilient to allow pressure to be applied through the material to actuate the switch in a manner to be set forth hereinafter. The casing 18 which embraces the actuating element 12, the insulating sleeves 16, and contact element 14 so as to hold the contact element 14 in spaced parallel relationship to the actuation element, is also preferably of a heat-shrinkable material such as "Kynar" to provide a corrosion resistant seal around the switching elements and also forms a durable, long-lasting cover for the switch. As mentioned before, the heat-shrinkable material retains its resiliency after shrinking so that pressure applied through the covering or casing 18 in the vicinity of the actuation gap 28 will cause the flexible closure elements 12 and 14 to move into engagement with each other thereby closing the switch. Release of the pressure, however, will allow the switch to automatically open due to the resiliency of the elements 12 and 14 of the heat-shrinkable material forming the sleeves 16. As will be appreciated, the lead wires 20 and 22 pass through one end of the heat-shrinkable casing or covering 18 and are sealed by the covering as it shrinks; and, to assure that the seal is completely water or moisture-proof, silicone rubber adhesive or similar sealant may be used to seal the end of the covering around the lead wires.

REferring now to FIG. 3, the hereinbefore described pressure-sensitive switch 10 is shown incorporated porated onto electro-surgical forceps 30 to control transmission of electric current from an electro-surgical source, not shown, to the tips 32 and 34 of the forceps. An electro-surgical source, or control unit which would be suitable for use with the forceps 30 is described in U.S. Pat. No. 3,100,489 issued to R. W. Bagley.

For clarity in describing the forceps 30, like parts of the pressure sensitive switch previously described have been given like reference numerals with a prime suffix. The electro-surgical forceps 30, with the exception of the pressure-sensitive switch 10', are conventional and have spaced arcuate arms 36 and 38 of a conductive material connected by wires 40 and 42 respectively to the electro-surgical source. The arms 36 and 38 are commonly joined at one end by an electric insulated connector 44 with the conductive operative tips 32 and 34 at their opposite ends disposed to be moved together for gripping engagement with skin tissue. The forcep arms 36 and 38 may include insulating coverings 46 which cover the entire arms except for the operative tips 32 and 34. The pressure-sensitive switch 10' may be incorporated onto the forceps 30 in one of several ways to best suit the desires of the surgeon. One application of the switch 10' to the forceps is shown in FIG. 3 with the switch 10' connected on an inner surface of the forcep arm 36 and with the covering 18' for the switch passing not only around the switching elements 12' and 14' but also around the associated arm 36 of the forceps so that the switch is securely and immovably attached to the arm. Preferably the switch 10' is disposed so that the contact element 14' lies closer to the arm 36 than the actuation element 12'. In this manner, a switch operating protrusion 48 secured to the opposite forcep arm 38 as with a heat-shrinkable sheathing 50 will be disposed to apply pressure in the actuation gap 28' between the insulating sleeves 16' on the actuation element when the tips 32 and 34 of the forceps are moved into engagement. The size of the protrusion 48 is preferably such that the switch 10' will not be closed unless a slight additional force is applied to the forcep arms after the tips have been moved together. The lead wires 20' and 22' from the conductive elements of the switch are connected to the electro-surgical supply. Alternately, one of the lead wires may be electrically connected directly to one of the operative tips of the forceps.

Another application of the pressure-sensitive switch is illustrated in FIG. 4 with like parts of the switch and the forceps given like reference numerals with a double prime suffix. The switch 10" is shown incorporated onto a pair of electro-surgical forceps 60. Basically, the switch 10" is the same as that shown in FIGS. 1 and 2 with the addition of a pushbutton actuator 62 adjacent to the actuation gap 28"The pushbutton actuator 62 may comprise a cylindrical pushbutton guide 64 that is disposed to rest on the insulating sleeves 16" in alignment with the actuating gap. The heat-shrinkable material covering 18" passes over the pushbutton actuator to positively position the actuator relative to the arm 36" of the forceps. A pushbutton 66 having a cylindrical body portion conforming in external size and shape with the internal dimensions of the guide 64, is disposed for sliding movement within the guide so that a reduced diameter foot portion 68 of the pushbutton can move the actuation element 12" into engagement with the contact element 14" when pressure is applied to the pushbutton. Pressure is applied through the heat-shrinkable covering 18" against the pushbutton 66 to cause it to slide inwardly within the guide. It will be seen with this arrangement of the pressure-sensitive switch, that the switch 10" is mounted on the outer surface of the forcep arm 36" so that the pushbutton is conveniently disposed for actuation by the fingers or thumb of the surgeon. As in the case of the arrangement shown in FIG. 3, the heat-shrinkable covering 18" passes around the switch elements as well as the associated arm 36" of the forceps to positively secure the switch and pushbutton actuator to the forceps.

A double switch embodiment 70 of the pressure-sensitive switch of the present invention is shown in FIG. 5. The double switch embodiment is seen to include first and second switch components 72 and 74 defined by first and second longitudinally aligned electric actuating elements 76 and 78 each having an electric insulating sleeve 80 and 82 respectively of a heat-shrinkable material around its outermost end and a common insulating sleeve 84 of a heat-shrinkable material around the innermost end of each actuating element to maintain the innermost ends in spaced non-contacting relationship. The three insulating sleeves 80, 82 and 84 define first and second actuating gaps 86 and 88 therebetween, similar to actuation gap 28 of the switch shown in FIG. 1. A common element 90 preferably made of the same conductive material as elements 76 and 78, e.g., a beryllium copper strip, or a similar material with good corrosion resistance, excellent electrical conductivity and high fatigue strength, is disposed in parallel spaced relationship with the actuation elements 76 and 78 against the external surface of the insulating sleeves. The actuation elements and the contact element are preferably flat elongated flexible strips which are resilient to resume their normal straight disposition shown in the drawings and each element as well as the insulating sleeves are encompassed with a covering 92 of a heat-shrinkable material so that either switch component can be operated by appropriate pressure applied in one of the gaps 86 or 88. The actuation elements 76 and 78 have lead wires 94 and 96 respectively connected thereto and the common contact element 90 has a lead wire 98 connected thereto which extends outwardly through the ends of the covering 92 for connection with the electrical circuit in which it is to be operative.

One application of the double switch embodiment 70 is shown in FIGS. 6 through 8 with like parts given like reference numerals with a prime suffix. In this application, the double switch 70' is incorporated into an electro-surgical pencil 100 which is used for both cutting and cauterizing functions.

The electro-surgical pencil 100 basically includes an elongated body 102 of a moldable plastic or other material which preferably will withstand temperatures up to 300.degree.F. The body 102 is provided with suitable cavities and passages for the reception of the double switch 70' and electrical lead wires to be described hereinafter. At the forward end of the body 102 of the pencil 100, an elongated axial recess 104 is provided for the reception of a conventional chuck 106 for releasably retaining a conventional electrode probe 108. The electrode probe 108 is designed to cut or cauterize skin tissue depending upon the frequency of the electrical current transmitted to the probe from a conventional electro-surgical generator or control unit which is not shown but which could be of the type shown in U.S. Pat. No. 3,100,489 with slight modification. The recess 104 is connected to a centrally located radially opening switch cavity 110 in the body of the pencil by a first passage 112 for electrical lead wires, as will be explained in more detail later, and the switch cavity 110 is connected by a second electrical lead wire passage 114 through the opposite end of the body of the pencil from which the electrical lead wires pass out of the pencil to the electro-surgical generator for supplying the current needed for the cutting or cauterizing procedures. The electro-surgical pencil 100 is shown with pushbutton actuators 116 of the type previously described in connection with the forceps of FIG. 4, wherein generally cylindrical pushbutton inserts 118 are disposed for sliding movement in outer concentric guides 120. However, the pushbutton actuators 116 are not necessary inasmuch as a double switch arrangement, as shown in FIG. 5, could be used wherein direct pressure is applied against the actuation elements 76' and 78' by the fingers or thumb of the surgeon. A heat-shrinkable covering 122 passes around the body 102 of the pencil fully enclosing the pushbutton actuators 116 so as to be sealed within the covering. In this way, either first or second switch component 72' or 74' of the pencil can be closed by the application of pressure through the heat-shrinkable covering against the associated push-button. Electrical lead wires from the electro-surgical generator pass through the lead wire passage 114 into the switch cavity 110 where first and second switch lead wires 94' and 96' are connected to the outermost ends of the actuation elements 76' and 78' respectively, and an active lead wire 124 is connected to the electrode chuck 106. A common lead wire 98' also from the electro-surgical generator is connected to the contact element 90' to complete the wiring of the pencil. The electro-surgical generator supplies a pre-selected radio frequency current to the electrode probe 108 dependent upon which switch component 72' or 74' of the pencil is closed. In other words, the first switch component 72' could be connected to the electro-surgical generator so that when it is closed a circuit with a predetermined electrical frequency would be completed through the electrode probe but when the second switch component 74' is closed, a circuit with a different frequency would be completed through the probe, one frequency being suitable for cutting skin tissue and the second frequency being suitable for cauterizing the skin.

In actual operation, the patient who is to be operated on with the pencil is grounded so that when the electrode-probe 108 is moved into engagement with the skin tissue of the patient, and one of the push-button actuators 118 is depressed to place a positive potential on the probe, a current will be completed through the body of the patient to effect the desired reaction with the patient's tissue. The same procedure of grounding the patient is followed when using the forceps 30.

A second embodiment of an electro-surgical pencil 130 is shown in FIG. 9 including a body portion 132 having an internal cavity 134 for the reception of a double switch 136, such as of the type shown in FIG. 5, an elongated axial recess 137 at the forward end of the body portion for the reception of a conventional chuck 138 for releasable retention of a conventional electro probe 140, and an offset rear passage 139 through which the electrical lead wires 143 are admitted into the body and prevented from being pulled out of the offset 145. The body portion 132 is notched at 141 in its forward most end so as to receive a collar 142 on the electro-probe which serves to positively position the probe relative to the body portion. As with the electro-surgical pencil 100, shown in FIGS. 6 through 8, the body portion 132 of the pencil is preferably made of a moldable plastic material capable of withstanding temperatures up to 300.degree.F. The body portion serves as a housing for the double switch 136 as well as the chuck 138 and electrical lead wires, generally designated 143, connecting the double switch to the chuck and to an electro-surgical supply which is not shown. Spaced openings 144 open through one flat side 146 of the body portion of the pencil into the internal cavity 134 in which the double switch 136 is disposed. The openings 144 are aligned with the actuation elements of the switch whereby pushbutton actuators 148 slidably retained in the openings by collars 150 will be operative upon fingertip pressure to effect selective engagement of the actuation elements with the contact element of the switch. To more positively guide the sliding movement of the pushbutton actuators 148, raised sleeves 152 are integrated with the body portion of the pencil in axial alignment with the openings 144 so that the pushbutton actuators are free to slide axially within the sleeves.

It will be appreciated that with this embodiment of the electro-surgical pencil an outer covering of a heat-shrinkable material is not needed since the cavity in which the double switch is retained is enclosed by the surrounding body portion and the pushbutton actuators 148 are positively guided for selective operation of the double switch.

It will, therefore, be seen that the pressure-sensitive switch of the present invention in its various embodiments is a very simple, reliable, well protected and long lasting switch which is well suited for use with electro-surgical instruments where reliability and simplicity of operation are most often critical. Also, the design of the switch gives the capability of being positively incorporated onto existing instruments or being made a part thereof during manufacture so that the switch is very attractive from a commercial standpoint.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.

Claims

What is claimed is:

1. A hand-actuated device for controlling the transmission of electrical current between an electro-surgical generator and a surgical electrode comprising in combination a body portion with a conductive socket for releasable retention of a surgical electrode, said body portion including means for mounting a dual switch assembly for effecting selected transmission of electrical current from an electro-surgical generator to the conductive socket, said dual switch comprising first and second electrically conductive actuating elements, spaced electric insulating sleeves around each of said actuating elements, actuating gaps between said insulating sleeves in which the actuating elements are exposed, an electrically conductive contact element adjacent to said insulating sleeves and slightly spaced from said actuating elements, said actuating elements movable to become temporarily engaged with said contact element in said actuation gaps, electrical leads connecting each of said actuation elements, said contact element, and said socket to an electro-surgical generator, pushbutton means including a pair of generally tubular guides in alignment with said actuating gaps and pushbuttons in said guides disposed for sliding movement therein to cause the aligned actuating element to move into engagement with said contact element, and a flexible covering around the body portion of the device including means covering said pushbutton means whereby pressure applied through said covering means against said pushbutton means will force said pushbutton means against the aligned actuating element causing it to move into contact with said contact element.

2. The hand-actuated device of claim 1 wherein said covering comprises a heat-shrinkable sleeve and said insulating sleeves are made of a heat-shrinkable material.

3. The hand-actuated device of claim 1 wherein said body portion comprises an elongated non-conductive housing, an interior cavity within said housing adapted to retain said dual switch, a pair of openings in said housing aligned with said first and second actuating elements and extending between an exterior surface of the housing and said interior cavity, and said pushbutton means being slidably retained in the guides within said openings to selectively effect engagement of said actuating elements with said contact element.

4. A hand-actuated device for controlling the transmission of electrical current between an electro-surgical generator and a surgical electrode comprising in combination a hardened insulating body having a recessed socket portion, a recessed switch mounting portion for the mounting of a dual switch means, and electrical lead wire retaining passages for electrical lead wires, an electrically conductive chuck in said recessed socket portion including means for releasably retaining a surgical electrode, dual switch means in said switch mounting portion, said dual switch means comprising first and second elongated flexible flat actuating strips of electrically conductive material, said actuating strips being longitudinally aligned, a first spacer sleeve of an electric insulating heat-shrinkable material covering adjacent ends of the actuating strips and retaining them in spaced relationship to one another, second and third electric insulating heat-shrinkable sleeves covering the opposite ends of said actuating strips, actuatioin gaps between said first insulating and said second and third insulating sleeves wherein the actuating strips are exposed, an elongated contact strip of an electrically conductive material adjacent said first, second and third insulating sleeves and extending parallel to and spaced from said actuating strips, a pair of pushbutton guides aligned with said actuation gaps on the opposite side of said actuating strips from said contact strip, said pushbutton being slidably received in said guides in a position to move the actuating strips into operative engagement with said contact strip when pressure is applied to said pushbuttons, electrical leads in said retaining passages, said electrical leads being individually connected to said actuating strips, said contact strip, and said chuck and passing out of the body for operative connection to an electro-surgical generator whereby engagement of either of said actuating strips with said contact strip will cause a preselected potential to be placed on said chuck, and a flexible heat-shrinkable covering around said body forming a seal around said actuating and contact strips whereby pressure applied through the flexible opening and against the pushbuttons will cause the pushbuttons to move the aligned actuating strip into engagement with the contact strip.