SHORT-WAVE THERAPY APPARATUS
BACKGROUND AND BRIEF DESCRIPTION OF
THE INVENTION 5
A diathermy apparatus for treatment of living matter essentially calls for the passage of an electrical current therethrough. The usual process is for RF energy to be applied to the human body and with the human body acting as a dialectric so that the current flow in the 10 body would be predicated on the amplitude of the pulse applied thereto as well as the pulse width and rate. It was found that the heat generated by this current flow produced a therapeutic effect and, while beneficial results obtained therefrom are not fully understood, this 1 ^ application of RF energy has been utilized for a number of years.
Prior art electrotherapeutic equipment utilize a single induction or treatment head which was tunable at
a resonant frequency for optimum transmission of RF energy into the body. The single head was sometimes tuned by varying the distance between two capacitance plates either directly on the head itself or internally of the cabinet normally associated therewith. In any 25 event, the apparatus required that the tuning be accomplished in conjunction with the patient's body for efficient operation.
The subject invention relates to an improved electrotherapeutic or short wave therapy apparatus which has 30 a single control system power supply operatively connected with two heads for inducing the RF energy into the patient or patient's body. The control system power supply includes a crystal oscillator which produces a standard 27.225 Mhz signal. This signal is fed to a pulse 35 modulator from thence to an RF buffer and an RF power amplifier, through a pi network and to the two induction treatment heads. The signal from the pi network to each treatment head is carried via a cable of selected length which have been calculated to assure a 40 constant output voltage under varying load conditions. This balancing of the heads results in an equalization of the power emission between the two.
A capacitive divider circuit is located before the pi network and provides a pick off point and a feedback 45 circuit to control the pulse rate and the pulse amplitude. The RF sample is picked off at the capacitive divider, peak rectified and delivered to a summing point. At the summing point, the peak rectified RF sample is compared with a reference and sent through a pulse 50 amplitude control circuit which operates in conjunction with a pulse rate control circuitry for finally biasing the pulse modulator in the appropriate direction to effect control of the pulse amplitude. Additionally, a monitoring oscilloscope is connected with the RF sam- 55 pie point to permit the visual observation of the apparatus operation.
The RF amplifier includes circuitry which will enable the grounded grid tetrode portion thereof to become ^ very stable and to operate with less grid current thereby prolonging the normal lifetime of the tube utilized therewith. Further, a leveling circuit will sense the output voltage and operate to control plate swing through a type of a servo mechanism. Finally, a timer circuit 65 will include a countdown and reset function so that the patient exposure time is both accurate and resettable by the mere activation of a switch.
The mechanical arrangement of the two headed electro-therapeutic apparatus includes a novel friction lock and a ball joint swivel construction that will permit maximum utilization of the induction treatment heads and the optimum positioning of same. The friction lock permits the arms to be locked by the manipulation of a knurled headed screw arrangement. The arms may then be movably positioned to an optimum patient location without readjustment of the knurled head. The block further includes the interleaving of a plurality of plates that are keyed at the articulated joint to alternated arms. This interleaving provides a multiple surface without having a large diameter surface for the fixed location of either arm on either side of the joint.
The above-mentioned ball joint design includes a notched socket joint and a tapered shaft interconnected with the ball so that the tapered shaft may be moved within the notch thereby fixedly locating the ball and associated head and also permitting additional movement of the associated head with respect to the socket location.
An object of the invention is to provide a uniquely constructed electrotherapeutic apparatus having at least two induction treatment heads with a single control system power supply.
Another object of the invention is to provide a uniquely constructed electrotherapeutic apparatus of the type known as diathermy equipment wherein one or more induction heads utilized therewith are fixed tuned. It is a feature of this object that the tuning of the head or heads may be accomplished at least in part by a coaxial cable or cables of a selected approximately quarter wave electrical length size.
A still further object of the invention is to provide a uniquely constructed electrotherapeutic treatment apparatus which is operable as a diathermy means for inducing RF energy into a patient's body and in which the amplifier circuitry therein includes a means for enabling same to become very stable and to operate with appreciably less grid current than was heretofore required.
A further object of the invention is to provide in a electrotherapeutic treatment apparatus, a unique leveling circuit which maintains constant output of voltage or peak intensity of the RF signal. It is a feature of this object that an RF sample is taken at the plate of a vacuum tube in the RF power amplifier and that this voltage is compared with a reference and used via feedback circuitry tube control the amplitude from the RF power amplifier.
A further object of the invention is to provide a pulse monitoring scope in an electrotherapeutic treatment apparatus. It is a feature of this object that an oscilloscope is mounted on the cabinet of said electrotherapeutic treatment apparatus and is connected to the plate of an RF power amplifier utilized therein. This voltage at the plate of the RF power amplifier accordingly permits the operator of the electrotherapeutic apparatus to monitor both the amplitude and the rate of the RF signal applied to the treatment head (or heads).
A significant object of the invention is to provide a uniquely constructed electrotherapeutic treatment apparatus which economizes on the use of internal circuitry but which substantially increases the treatment