Disposable electrosurgical handpiece
View Patent ↗Incorporating into an electrosurgical handpiece a device configured to disable the handpiece when a built-in usage time period expires. Preferably, the device comprises a timer in the form of an activating battery with a known discharge rate such that the battery voltage gradually reduces in value with use. The battery in turn is coupled to a circuit which monitors the battery voltage and operates a switch which decouples the handpiece electrode from the electrosurgical current source when the battery voltage falls below a preset value. This effectively disables the handpiece preventing reuse.
1. A disposable electrosurgical handpiece comprising:
a) a sealed enclosure having at one end means for connecting to an RF cable and at the opposite end an electrosurgical electrode,
b) inside the enclosure are:
i. an activating voltage source whose output voltage is time dependent,
ii. a voltage detector connect to the voltage source for monitoring its output voltage,
iii. a switch actuable by the voltage detector upon the output voltage reaching a predetermined value,
iv. the switch including a circuit electrically connecting the RF cable to the electrosurgical electrode,
c) means accessible from outside the enclosure for activating the voltage source such that the switch circuit electrically connecting the RF cable to the electrosurgical electrode is enabled,
d) the switch circuit electrically connecting the RF cable to the electrosurgical electrode becoming disabled upon the output voltage reaching its predetermined value after a certain time period has elapsed.
2. The disposable electrosurgical handpiece as claimed in claim 1 , wherein the activating voltage source is a battery.
3. The disposable electrosurgical handpiece as claimed in claim 2 , wherein a fixed load is connected across the battery such that its output voltage exhibits a known discharge rate.
4. The disposable electrosurgical handpiece as claimed in claim 1 , wherein the enclosure seals off the activating voltage source.
5. The disposable electrosurgical handpiece as claimed in claim 1 , wherein the means of claim element c) comprises a pull tab connected to the battery for activating the battery when pulled.
6. The disposable electrosurgical handpiece as claimed in claim 1 , wherein the switch comprises a relay having contacts when closed electrically connecting the RF cable to the electrosurgical electrode, the relay including an activating coil for the contacts.
7. The disposable electrosurgical handpiece as claimed in claim 6 , wherein a driver transistor is connected between the voltage detector and the relay activating coil.
8. The disposable electrosurgical handpiece as claimed in claim 7 , further comprising a light indicator connected to the transistor and activated when the transistor is activated.
9. The disposable electrosurgical handpiece as claimed in claim 1 , wherein the electrode is fixed to the enclosure.
10. A method for limiting the lifetime of an electrosurgical handpiece having an RF circuit connecting a cable connector at one end to an electrode at the opposite end, comprising:
a. providing inside the handpiece a voltage source having a controlled reduction of output voltage as a function of time,
b. providing means for a user to connect the voltage source to and to enable the RF circuit thereby enabling the handpiece, the connected voltage source's output voltage reducing as time elapses,
c. monitoring the voltage source's output voltage while the handpiece is enabled,
d. automatically disconnecting the RF circuit to disable the handpiece upon the voltage source's output voltage having fallen to a predetermined value.