GB2120901A

GB2120901A - Stethoscope

Info

Publication number: GB2120901A
Application number: GB08313216A
Authority: GB
Inventors: Osamu Ide; Fujio Tamura
Original assignee: Seiko Instruments Inc
Current assignee: Seiko Instruments Inc
Priority date: 1982-05-28
Filing date: 1983-05-13
Publication date: 1983-12-07
Also published as: GB8313216D0; GB2120901B; JPS58206722A

Abstract

A stethoscope has means (1,2,3,21) for rendering the cardiac sounds of a patient audible and means (6,7,11) for simultaneously displaying the pulse rate of the patient. <IMAGE>

Description

SPECIFICATION Stethoscope The present invention relates to a stethoscope.

A conventional stethoscope for a doctor is provided with only a resonance plate, an acoustic resonator for amplifying the cardiac sounds, and tubing for conducting the cardiac sounds, so as to isolate them from other noises, to the ears of the doctor. Thus it is impossible for the doctor, when he is listening to these cardiac sounds, simultaneously to count the number of pulses of the patient's heart.

This is a considerable disadvantage since it takes 0.5-1 minute to countthe number of pulses of the patients heart.

Although, therefore, the invention is primarily directed to any novel integer or step, or combination of integers or steps, as herein described and/or as shown in the accompanying drawings, nevertheless according to one particular embodiment of the present invention, to which however the invention is in no way restricted, there is provided a stethoscope having means for rendering the cardiac sounds of a patient audible, and means for simultaneously displaying the pulse rate of the patient.

Preferably, the means for simultaneously displaying the pulse rate of the patient comprise means responsive to said cardiac sounds.

Preferably also the means for rendering the cardiac sounds of the patient audible comprise an acoustic resonator which carries the means respon size to said cardiac sounds.

The acoustic resonator may be mounted at the back of a resonance plate to provide a resonance chamber therebetween, there being a conduit which communicates with said chamber and which is adapted for the transmission of the cardiac sounds.

Preferably, the means responsive to said cardiac sounds comprises a microphone which is connected to an electronic circuit, the electronic circuit being arranged to transmit signals to a display member which displays the patient's pulse rate. The microphone is preferably mounted in a hole in the acoustic resonator.

There is preferably a switch for rendering the electronic circuit operable.

The said switch is preferably adapted to be operated while the stethoscope is held against the patient to hear the cardiac sounds.

The display member may have a flashing portion which flashes whenever the electronic circuit detects the cardiac sounds.

The invention is illustrated, merely by way of example, in the accompanying drawings, in which: Figure 1 is a perspective view showing an embodiment of a stethoscope according to the present invention, Figure 2 is a sectional view of the stethoscope shown in Figure 1, Figure 3 is an exploded view of the stethoscope shown in Figures 1 and 2, Figure 4 illustrates the display provided on a pulse display portion of the stethoscope shown in Figures 1 and 3, and Figure 5 is a block diagram of a pulse rate display circuit which forms part of the stethoscope of Figures 1-3.

Referring to the drawings, Figure 1 is a perspective view showing an embodiment of a stethoscope according to the present invention seen from the rear side. The stethoscope comprises a resonance plate 1 which may be held by the doctor against the patient's chest or back, the resonance plate 1 being responsive to the sounds of the patient's heart. An acoustic resonator 2 is mounted at the back of the resonance plate 1 to provide a resonance chamber la therebetween for the amplification of the cardiac sounds, there being a tube or conduit 3 which communicates with the resonance chamber 1a and which is adapted for the transmission of the cardiac sounds. These cardiac sounds are transmitted to the ears of the doctor by tubing 21 connected to the conduit 3. An electronic circuit housing 4 is provided at the rear of the acoustic resonator 2.A pulse display member 6 is provided at the rear of the electronic circuit housing 4. A switch 5 for operating the pulse display member 6 is provided at the side of the housing 4. When the doctor applies the stethoscope to a patient's breast or back and puts the switch 5 and the housing 4 between his fingers, the pulse rate is displayed on the pulse display member 6 simultaneously with the cardiac sounds being heard by way of the tubing 21.

Figure 2 shows a sectional view of a main portion of the stethoscope shown in Figure 1. A microphone 7 for detecting cardiac sounds and a packing 8 are mounted in a hole 2a provided in a part of the acoustic resonator 2. Cardiac sound signals which are received by the microphone 7 are transmitted from projecting electrodes 9 at the rear of the microphone 7 to an electronic circuit substrate or board 11 via spring electrodes 10. The spring electrodes 10 press against the projecting electrodes 9 of the microphone 7 to fix the latter in position. The cardiac sound signals are processed by the electronic circuit substrate 11 so as to be displayed on the pulse display member 6.

Figure 3 shows an exploded view of each compo nentofthestethoscopeshown in Figures 1 and 2.

The resonance plate 1 is secured to the acoustic resonator 2 by a frame 22. As indicated above, the microphone 7 is embedded in the hole 2a provided in the acoustic resonator 2 through the packing 8, and is secured in position by the spring electrodes 10 which are provided at the rear of the electronic circuit substrate 11 and which press against the projecting electrodes 9 of the microphone 7. The spring electrodes 10 are secured to the electronic circuit substrate 11 by pins 14. The electrodes 9 of the microphone 7 are thus simultaneously connected to the electronic circuit substrate 11. Secured to the electronic circuit substrate 11 are the pulse display member 6, a miniature battery 12 and a micro-switch 16 for connecting and disconnecting the power of the battery 12 to a cardiac signal processing circuit which is shown in Figure 5 and is described below.The miniature battery 12, which serves as the power source of the cardiac signal processing circuit, is secured to the electronic circuit substrate 11 by a battery securing electrode 17 which is itself secured to the electronic circuit substrate 11 by a pin 20. The electronic circuit substrate 11 is secured to the acoustic resonator 2 by screws 15 which pass through spacers 13, the parts 6-15 being covered by the electronic circuit housing 4. The housing 4, which is secured to the acoustic member 2, is provided with a window 18a having an inner protective glass 18 and an opening 19a through which passes a rubber switch cover 19 which covers the micro-switch 16, the micro-switch 16 and cover 19 collectively forming the switch 5 shown in Figure 1. The conduit 3 for conducting the cardiac sounds is screwed into the acoustic resona tor2.

Figure 4 is an example of a display pattern which may be used on the pulse display member 6. A flashing mark 23 for indicating cardiac sound pulses flashes whenever the electronic circuit detects the cardiac sounds. Pulses are displayed on a pulse rate display portion 24 whenever several cardiac sound pulses are detected, the display being held until the next cardiac sound pulses are detected, when the pulse rate displayed is adjusted if necessary.

Figure 5 shows a block diagram of the electronic circuit for displaying the pulse rate according to the present invention. Cardiac sounds which reach the microphone 7 are converted into electrical signals which are amplified by a pre-amplifier 25 and pass through a band-pass filter 26 which passes only the components of the signals which correspond to cardiac sounds. The signals from the band-pass filter 26 are further amplified by a main amplifier 27, inputted to a level detector 28, and are converted into pulse signals. The interval between the cardiac sound pulses of the cardiac sound pulse signals is counted by a counter 29 and is converted into the number of pulses per 1 minute by a ROM 30 for converting the number of pulses.This number of pulses, constituting the pulse rate, is also converted into a signal for driving the pulse display member 6 by way of a decoder 31 which includes a hold function, whereby the pulse rate is displayed on the pulse display member 6. The counter 29, the ROM 30 and the decoder 31 are controlled by signals from a standard clock source 32.

As illustrated above, both the pulse rate and the cardiac sounds can be determined simultaneously by the stethoscope described above. Since the cardiac sounds are used as a pulse counting device with the aid of an electronic circuit, the device is not affected by outside electrical noises such as an AC power source, nor is the patient required to touch an electrode with his finger. Moreover, any misoperation of the electronic circuit can be detected since the pulses are derived from the cardiac sounds which can be heard by the doctor who will also ensure that the flashing mark 23 is operating.

Claims

1. A stethoscope having means for rendering the cardiac sounds of a patient audible; and means for simultaneously displaying the pulse rate of the patient.

2. A stethoscope as claimed in claim 1 in which the means for simultaneously displaying the pulse rate of the patient comprise means responsive to said cardiac sounds.

3. A stethoscope as claimed in claim 2 in which the means for rendering the cardiac sounds of the patient audible comprise an acoustic resonator which carries the means responsive to said cardiac sounds.

4. A stethoscope as claimed in claim 3 in which the acoustic resonator is mounted at the back of a resonance plate to provide a resonance chamber therebetween, there being a conduit which communicates with said chamber and which is adapted for the transmission of the cardiac sounds.

5. A stethoscope as claimed in claim 3 or 4 in which the means responsive to said cardiac sounds comprises a microphone which is connected to an electronic circuit, the electronic circuit being arranged to transmit signals to a display member which displays the patient's pulse rate.

6. A stethoscope as claimed in claim Sin which the microphone is mounted in a hole in the acoustic resonator.

7. A stethoscope as claimed in claim 5 or 6 comprising a switch for rendering the electronic circuit operable.

8. A stethoscope as claimed in claim 7 in which the said switch may be operated while the stethoscope is held against the patient to hear the cardiac sounds.

9. A stethoscope as claimed in any of claims 5-8 in which the display member has a flashing portion which flashes whenever the electronic circuit detects the cardiac sounds.

10. A stethoscope substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

11. A stethoscope for use in medicine comprising: a resonance plate for receiving cardiac sounds; an acoustic resonator provided at the rear of said resonance plate; and a conduit for conducting the cardiac sounds from said acoustic resonator to the ears of a doctor, wherein said stethoscope is provided with a microphone at a part of said acoustic resonator to convert sounds including the cardiac sounds into electrical signals, and said electrical signals are processed in an electronic circuit for detecting, counting and displaying the cardiac sound signals.

12. A stethoscope as claimed in claim 11 further comprising a pulse display portion for displaying the cardiac sound signals, and a switch for controlling said pulse display portion and attached to a housing.

13. Any novel integer or step, or combination of integers or steps, hereinbefore described, irrespective of whether the present claim is within the scope of, or relates to the same or a different invention from that of, the preceding claims.