Safety circuitry for high frequency cutting and coagulating devices

Claim 2

In combination: apparatus for the surgical cuttting and/or coagulation of tissue, said apparatus being adapted to utilize high frequency electrical currents derived from a generator of high frequency electrical current, said generator having a first and a second output contact, said apparatus including an outer tube whose outer surface is at least partially made of metallic conductive material intended in use to be in conductive contact with tissue inside the human body, a conductive probe functioning as an electrode supported by, but insulated from, the conductive portions of said outer tube, a second electrode detached from said outer tube and probe and intended to remain outside the human body in conductive contact with said human body, a first conductive lead means for interconnecting the first contact to the probe, and second conductive lead means for connecting the second contact to the second electrode; and safety circuit means conductively interconnecting the said metallic conductive material of said outer tube to said second conductive lead means, said safety circuit means providing an impedance not less than about 100 ohms, whereby said outer tube functions at a voltage intermediate between said contacts during normal operation as a consequence of current flow from said probe to said outer tube.

Claim 3

Apparatus according to claim 1 in which means is provided in said circuit means to measure and indicate the value of the voltage across, or the current which passes through, said circuit means.

Claim 4

Apparatus according to claim 2 in which a value limit is determined for said circuit means, and in which said circuit means includes means to signal when the said voltage or current exceeds said value limit.

Claim 5

Apparatus according to claim 3 in which said impedance is not greater than about 1,000 ohms.

Claim 6

Apparatus according to claim 3 in which value means is provided to determine said value limit, said value means including proportionalizing means to set the value limit as a percentage of the actual value of the output current or voltage of said generator, and also to limit the maximum value limit.

Claim 7

Apparatus according to claim 5 in which said impedance is not greater than about 1,000 ohms.

Claim 8

Apparatus according to claim 3 in which control means is provided which control the generator to reduce its current output when the value limit is exceeded.

Claim 9

Apparatus according to claim 3 in which the signal means is provided with latch means to hold the signal in operation for a period of time after the value limit was exceeded independently of the actual voltage or current in said circuit means.

Claim 10

Apparatus according to claim 3 in which said value limit is a constant maximum value which when exceeded causes said means to signal to function.

Claim 11

Apparatus according to claim 2 in which said impedance is not greater than about 1,000 ohms.

Claim 12

In combination: apparatus for the surgical cutting and/or coagulation of tissue, said apparatus being adapted to utilize high frequency electrical currents derived from a generator of high frequency electrical current, said generator having a first and a second output contact, said apparatus including an outer tube which is at least partially made of metallic conductive material, said outer tube being intended in use to be in contact with tissue inside the human body, a conductive probe functioning as an electrode supported by, but insulating from, the conductive portions of said outer tube, a second electrode detached from said outer tube and probe and intended to remain outside the human body in conductive contact with said human body, a first conductive lead means for interconnecting the first contact to the probe, and second conductive lead means for connecting the second contact to the second electrode, some portions of the metallic conductive material being subject to inclusion in an electrical circuit from the probe to tissue inside the human body into which the outer tube has been inserted or to the surgeon, either by direct contact therewith or through a substance which contacts said portion and said tissue or said surgeon; and safety circuit means conductively interconnecting the said metallic conductive material of said outer tube to said second conductive lead means, said safety circuit means providing an impedance not less than 100 ohms, whereby said outer tube functions at a voltage intermediate between said contacts during normal operation as a consequence of current flow from said probe to said outer tube.

Claim 13

In combination: apparatus for the surgical cutting and/or coagulation of tissue, said apparatus being adapted to utilize high frequency electrical currents derived from a generator of high frequency electrical current, said generator having a first and a second output contact, said apparatus including an outer tube which is at least partially made of metallic conductive material, said outer tube being intended in use to be in contact with tissue inside the human body, a conductive probe functioning as an electrode supported by, but insulating from, the conductive portions of said outer tube, a second electrode detached from said outer tube and probe and intended to remain outside the human body in conductive contact with said human body, a first conductive lead means for interconnecting the first contact to the probe, and second conductive lead means for connecting the second contact to the second electrode, some portions of the metallic conductive material being subject to inclusion in an electrical circuit from the probe to tissue inside the human body into which the outer tube has been inserted or to the surgeon, either by direct contact therewith or through a substance which contacts said portion and said tissue or said surgeon; and safety circuit means conductively interconnecting the said metallic conductive material of said outer tube to said second conductive lead means, said safety circuit means providing an impedance not less than 100 ohms, whereby said outer tube functions at a voltage intermediate between said contacts during normal operation as a consequence of current flow from said probe to said outer tube.

Claim 14

Apparatus according to claim 11 in which means is provided in said circuit means to measure and indicate the value of the voltage across, or the current which passes through, said circuit means.

Claim 15

Apparatus according to claim 12 in which a value limit is determined for said circuit means, and in which said circuit means includes means to signal when the said voltage or current exceeds said value limit.

Claim 16

Apparatus according to claim 13 in which said impedance is not greater than about 1,000 ohms.

Claim 17

Apparatus according to claim 13 in which value means is provided to determine said value limit, said value means including proportionalizing means to set the value limit as a percentage of the actual value of the output current or voltage of said generator, and also the limit the maximum value limit.

Claim 18

Apparatus according to claim 15 in which said impedance is not greater than about 1,000 ohms.

Claim 19

Apparatus according to claim 13 in which control means is provided which control the generator to reduce its current output when the value limit is exceeded.

Claim 20

Apparatus according to claim 13 in which the signal means is provided with latch means to hold the signal in operation for a period of time after the value limit was exceeded independently of the actual voltage or current in said circuit.

Claim 21

Apparatus according to claim 13 in which said value limit is a constant maximum value which when exceeded causes said means to signal to function.

Claim 22

Apparatus according to claim 12 in which said impedance is not greater than about 1,000 ohms.