High-frequency electrosurgical unit with timed safety shut down interlock

• US 4,658,815 A
• Filed: 01/15/1986
• Issued: 04/21/1987
• Est. Priority Date: 07/28/1982
• Status: Expired due to Fees

• Current Assignee: Erbe Elektromedizin GmbH (C. Erbe GmbH)
• Original Assignee: Erbe Elektromedizin GmbH (C. Erbe GmbH)
• Inventors: Farin, Gunter, Putz, Peter
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/819,468
• Time in Patent Office: 461 Days
• Field of Search: 128/303.13, 128/303.14, 128/303.17, 128/419 R, 364/707
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/1273 including multiple generators in one device

Abstract

A supplementary acoustic warning signal is provided for a high-frequency electrosurgical unit which sounds only after the lapse of an interval set by a first delay circuit shows that one of the high-frequency generators in the unit remains active longer than what, on the average, is normal. A second delay circuit is provided to assure shut-off of the high-frequency generators if at least one of the high-frequency generators remains active without interruption longer by an interval set by a second delay circuit beyond the lapse of an interval of the interval set by the first delay circuit. The supplementary acoustic signal thus sounds before the second delay circuit shuts off the high-frequency generators. The intervals determined by each of the delay circuits are adjustable. The output signal of the second delay circuit which activates the shut-off relays is maintained until a switch is operated to reset the system, so that the malfunction which has led to shut-down will be dealt with before the unit is used again.

Claims

1. High-frequency electrosurgical unit for cutting and coagulating biological tissues, including at least one high-frequency generator capable of being individually put into and taken out of operation by control of an enabling circuit thereof including a main power on-off switch, said at least one high-frequency generator having a high-frequency transformer, said unit also comprising:

a rectifier circuit individual to said high-frequency transformer of said at least one high-frequency generator for providing a first electrical output signal (u₁) when and so long as said at least one high-frequency generator is in an activated state;

a first delay circuit (13), to which said first output signal (u₁) is provided as an input, for producing a second output signal (u₂) when said first output signal (u₁) has persisted without interruption for more than a first time interval (t₁₃), said first delay circuit having means for adjusting the duration of said first time interval;

means (14) connected to said first delay circuit (13) for producing an audible signal for so long as said second output signal (u₂) of said first delay circuit (13) persists;

a second delay circuit (15) having said second output signal (u₂) of said first delay circuit (13) as an input, for producing a third output signal (u₃) when said second output signal (u₂) has persisted without interruption for more than a second time interval (t₁₅), said second delay circuit (15) having means for adjusting the duration of said second time interval;

cut-off relay means (16,17) having a switching path interposed in said enabling circuit and connected to allow completion of said enabling circuit when said at least one one high-frequency generator is put into operation and to interrupt said enabling circuit immediately at the end of said second time interval (t₁₅) in response to said third output signal (u₃) of said second delay circuit (15), and

means for restoring enablement of said at least one high-frequency generator and restarting said second delay circuit (15) after interruption of said enabling circuit by said cut-off relay means in response to turning off said main power switch and quickly thereafter turning said main power switch back on.

2. High-frequency electrosurgical unit according to claim 1, in which there are a plurality of said high-frequency generators each having an enabling circuit, a high-frequency transformer and a rectifier circuit individual thereto for producing an individual first output signal and in which said means (14) for producing an audible signal, first delay circuit (13), and second delay circuit (15) serve all said high-frequency generators, said cut-off relay means being an individual cut-off relay for each said high-frequency generator, said means for restoring enablement being effective for restoring enablement of all said high-frequency generators which were enabled prior to disablement by said cut-off relay means, said first delay circuit being connected for being made operable, in response to said first output signals of said rectifier circuits, while any of said high-frequency generators is in operation and said second delay circuit being continued in operation, after responding to said second output signal of said first delay circuit, so long as any of said high-frequency generators continues in operation.

3. High frequency electrosurgical unit according to claim 2, in which the output signals of said rectifier circuits respectively connected to said high-frequency generators are connected in common through individual output diodes (2,4) to the input of said first delay circuit at which is connected the input of a first inverter circuit (IC1) which is a component of said first delay circuit, said first delay circuit also comprising an adjustable resistance (R5) likewise connected to the input of said first delay circuit and a capacitor (C5) connected between a grounding potential and the end of said adjustable resistor not connected to said delay circuit input, a second inverter unit (IC2) with its input connected the junction of said adjustable resistor with said capacitor and its output connected to a first input of a NOR-gate (IC3), the output of said first inverter circuit being connected to a second input of said NOR-gate, the output of said NOR-gate being connected to the output of said first delay circuit (13), first and second diodes (D5, D6) being provided respectively across said adjustable resistor and said capacitor and being provided respectively for discharging said capacitor through said rectifier circuit (11, 12) when said output voltage of said rectifier circuit goes to zero and for limiting negative input voltage to said second inverter circuit (IC2).

4. High-frequency electrosurgical unit according to claim 2, in which said means for restoring enablement of said high-frequency generators comprises first and second NAND gates (IC5 and IC6) in said second delay circuit (15) connected together to constitute a RS flipflop, said second NAND-gate (IC6) having one input to which a signal (u₉) of said second delay circuit is provided and an output serving as the output providing said third output signal (u₃) of said second delay circuit, said first NAND-gate (IC5) having an input connected to a network energized by a supply voltage (U₃) of said electrosurgical unit energized through said main power switch (23), a second input of each of said NAND-gates being cross-connected to the output of the other of said NAND-gates, whereby brief interruption of said supply voltage (U₃) will terminate said third output signal (u₃) produced by operation of said second delay circuit (15).

5. High-frequency electrosurgical unit according to claim 4, in which a reset button switch is connected to said input of said first NAND-gate (IC5) for momentarily grounding said network connected to said supply voltage and thereby terminating said third output signal (u₃) produced by said second delay circuit (15).

6. High-frequency electrosurgical unit according to claim 4, in which said second delay circuit includes an adjustable resistor connected between the input of said second delay circuit and the input of an inverter circuit (IC4) and also a capacitor connected between said input of said inverter circuit and ground potential, said adjustable resistor and said capacitor being bridged by diodes in the same manner as and for the same purpose as the corresponding components of said first delay circuit, a resistor (R11) between the input of said second delay circuit and ground potential being connected for discharging said capacitor (C6) of said second delay circuit through the diode (D7) bridging said adjustable resistor when said second output voltage (u₂) of said first delay circuit drops to zero, the output of said inverter circuit and (IC4) being provided through a differentiating network to an input of said second NAND-gate (IC6) of said enablement restoring means.

7. High-frequency electrosurgical unit according to claim 4, in which said network energized by said supply voltage (U₃) and said first NAND-gate (IC5) of said enablement restoring means comprises a resistor R7 interposed between said supply voltage and an input of said first NAND-gate and a capacitor (C7) connected between said input of said first NAND-gate and ground potential, both said resistor and said capacitor connected to said input of said first NAND-gate being bridged respectively by diodes, and an additional resistor (R8) being connected between said supply voltage and ground potential, whereby the application of said supply voltage to said first NAND-gate following operation of said main power switch for turning on said high-frequency electrosurgical circuit is delayed at the input of said first NAND-gate for assuring a defined setting of said RS flipflop constituted by said first and second NAND-gates, and whereby when said supply voltage is interrupted, said capacitor (C7) connected to said first NAND-gate is discharged through said additional resistance (R8) and the said diode bridging said resistor (R7) interposed between said first NAND-gate and said supply voltage.

8. High-frequency electrosurgical unit according to claim 1, further comprising manual-reset means for restoring enablement of said at least one high-frequency generator and restarting said second delay circuit (15) after interruption of said enabling circuit by said cut-off relay means, said manual-reset means including a manually operable switch.

9. High-frequency electrosurgical unit according to claim 1, in which said means of said first and second delay circuits for respectively adjusting first and second time intervals have a range of adjustment that permits the sum of the durations of the first and second time intervals (t₁₃ +t₁₅) to be greater than any likely normal uninterrupted activiation period of said at least one of high frequency generator.

10. High-frequency electrosurgical unit according to claim 1, in which said at least one high-frequency generator is a self-excited high-frequency generator (6) having its own output adjustment by which its output power can be set at any value within a wide range, and in which said rectifier connected to said high-frequency transformer (7) of said at least one high frequency generator (6) includes a voltage limiting diode (D4A) connected so as to limit the voltage output of said rectifier (12).

11. High-frequency electrosurgical unit according to claim 1, in which said first delay circuit includes a first inverter circuit (IC1) having its input connected directly to the input of said first delay circuit for inverting said first output signal of said rectifier, an adjustable resistance (R5) likewise connected to the input of said first delay circuit and a capacitor (C5) connected between the end of said adjustable resistor not connected to said delay circuit input and a grounding potential, a second inverter unit (IC2) connected between the junction of said adjustable resistor with said capacitor and a first input of a NOR-gate (IC3), the output of said first inverter circuit being connected to a second input of said NOR-gate, the output of said NOR-gate being connected to the output of said first delay circuit (13), first and second diodes (D5, D6) being provided respectively across said adjustable resistor and said capacitor and being provided respectively for discharging said capacitor through said rectifier circuit (11, 12) when said output voltage of said rectifier circuit disappears and for limiting negative input voltage to said second inverter circuit (IC2).

12. High-frequency electrosurgical unit according to claim 1, in which said means for restoring enablement of said at least one high-frequency generator comprises first and second NAND gates (IC5 and IC6) in said second delay circuit (15) connected together to constitute a RS flipflop, said second NAND-gate (IC6) having one input to which a signal (u₉) of said second delay circuit is provided and an output serving as the output providing said third output signal (u₃) of said second delay circuit, said first NAND-gate (IC5) having an input connected to a network energized by a supply voltage (U₃) of said electrosurgical unit energized through said main power switch (23), a second input of each of said NAND-gates being cross-connected to the output of the other of said NAND-gates, whereby brief interruption of said supply voltage (U₃) will terminate said third output signal (u₃) produced by operation of said second delay circuit (15).

13. High-frequency electrosurgical unit according to claim 12, in which a reset button switch is connected to said input of said first NAND-gate (IC5) for momentarily grounding said network connected to said supply voltage and thereby terminating said third output signal (u₃) produced by said second delay circuit (15).

14. High-frequency electrosurgical unit according to claim 12, in which said second delay circuit includes an adjustable resistor connected between the input of said second delay circuit and the input of an inverter circuit (IC4) and also a capacitor connected between said input of said inverter circuit and ground potential, said adjustable resistor and said capacitor being bridged by diodes in the same manner as and for the same purpose as the corresponding components of said first delay circuit, a resistor (R11) between the input of said second delay circuit and ground potential being connected for discharging said capacitor (C6) of said second delay circuit through the diode (D7) bridging said adjustable resistor when said second output voltage (u₂) of said first delay circuit drops to zero, the output of said inverter circuit and (IC4) being provided through a differentiating network to an input of said second NAND-gate (IC6) of said enablement restoring means.

15. High-frequency electrosurgical unit according to claim 12, in which said network energized by said supply voltage (U₃) and said first NAND-gate (IC5) of said enablement restoring means comprises a resistor R7 interposed between said supply voltage and an input of said first NAND-gate and a capacitor (C7) connected between said input of said first NAND-gate and ground potential, both said resistor and said capacitor connected to said input of said first NAND-gate being bridged respectively by diodes, and an additional resistor (R8) being connected between said supply voltage and ground potential, whereby the application of said supply voltage to said first NAND-gate following operation of said main power switch for turning on said high-frequency electrosurgical circuit is delayed at the input of said first NAND-gate for assuring a defined setting of said RS flipflop constituted by said first and second NAND-gates, and whereby when said supply voltage is interrupted, said capacitor (C7) connected to said first NAND-gate is discharged through said additional resistance (R8) and the said diode bridging said resistor (R7) interposed between said first NAND-gate and said supply voltage.