JPH01181101A - Contact safety device - Google Patents

Abstract

PURPOSE:To improve the safeness of a contact safety device by detecting the non-contact, contact and disconnection states respectively based on the voltage value of a resistance connected in parallel with a switch which detects a contact state with an object to be detected in case a medical diagnosing device, etc., are partly moved. CONSTITUTION:When a diagnosing device is operated normally and has no contact with an object to be detected, etc., a tape switch S1 is turned off and the voltage value VR applied to a resistance R10 is equal to the divided voltage value of a resistance R1. The value VR is applied to comparators IC1 and 2 respectively and compared with voltage levels Vu and Vl which are kept constant by Zener diodes 3 and 4. These levels Vu and Vl are set as O<Vl<Vr<Vu<V and the outputs of both IC1 and 2 are set at -V. The two-input of a logic circuit IC3 is set at zero together with the output also set at zero. Thus the circuit IC3 is kept under a workable state. In a contact state the switch S1 is turned on and the outputs of the IC1 and 2 are respectively set at -V and +V when, the output of the IC3 is equal to one.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a medical diagnostic device, and particularly to a safety device for preventing danger due to malfunction of the device.

(Prior art) For example, in an X-ray diagnostic device, as shown in FIG.
An X-ray generator 5 and an X-ray detector 6 are arranged opposite to each other with a top plate 4 on which a subject 3 is placed.

During diagnosis, the X-ray generator 5 or the X-ray detector 6 is moved vertically to a predetermined position by a control device (not shown). The X-ray generator 5 and the X-ray detector 6 are normally used without coming into contact with the subject or other equipment, but in the unlikely event that they come into contact with the subject due to a malfunction or failure of the control device, the This may not only cause damage to the device, but also pose a danger to the subject. Therefore, X
A control device of a radiographic diagnostic device is equipped with a means for detecting a state of contact with a subject or another device, stopping the device, and issuing an alarm. Subject 3 of X-ray generator 5 and X-ray generator 6
A tape switch 7 is provided in a portion facing the subject, and when the tape switch 7 comes into contact with a subject or the like and is pressed, a circuit is closed, and a detection circuit (not shown) stops the apparatus and issues an alarm. FIG. 5 is a schematic diagram of the switch portion of the X-ray generator 5. A tape switch 7 is provided along the outer periphery of the X-ray generator 5. FIG. 6 is an explanatory diagram showing the operating state of the tape switch 7. X-ray generator body 8
The tape switch 7 and the cover 10 are respectively attached via springs 9a and 9b, and in the non-contact state shown in FIG. 6(A), the tape switch 7 and the cover 1
0 is not in contact. As shown in FIG. 6(B), when the X-ray generator 5 comes into contact with a subject or the like, the spring 9b contracts and is pushed by the cover 10, which connects the tape switch 7. When the subject or the like is evacuated, the spring 9b is expanded and the tape switch 7 is turned off.

FIG. 7 shows a configuration diagram of a conventional contact safety device.

By opening and closing the tape switches 7a and 7b, the detection circuit 11 connected to the tape switches 7a and 7b is activated, and the drive circuit 12 that drives the X-ray generator and the X-ray detector can be stopped and an alarm can be issued.

FIG. 7 shows a state in which the tape switch is open, that is, a state in which the device is operating normally. When a subject or the like comes into contact with the apparatus and at least one of the tubes 7a and 7b is closed, the relay Ry1 is activated and the switch RyIB is closed. Then, relay Ry3 is activated and switch Ry3A is activated.
closes and Sui Sochi RY3B opens. switch R)'3
When B is opened, the drive circuit 12 is cut off, the X-ray diagnostic apparatus is stopped, and an alarm is issued. - Once the tape switch is closed,
Even after the test subjects were evacuated and the TAB Sui Sochi opened, the circuit including relay Ry3 remained closed, forming a self-holding circuit, and switch Ry3B remained open, stopping the X-ray diagnostic equipment. It remains as it is. When reset switch 13 is closed, relay Ry2 is activated and switch R is activated.
Y2A opens and switch RY2A opens, which turns off relay Ry3, which closes switch Ry3B.
The X-ray diagnostic device becomes operational again. After the reset/soto switch 13 is closed, it automatically opens and the detection circuit becomes open, returning to a normal state in which the detection circuit 11 does not operate.

By the way, in many cases of X-ray diagnostic equipment, the diagnostic section that includes the X-ray generator, bed, etc., and the control section that controls their movement are located in separate locations, and the tape switch provided in the X-ray generator In some cases, the wire connection from 7 to the detection circuit 11 in the control section is 20 m or more. However, in the contact safety device described above, if the connection from the tape switch 7 to the detection circuit 11 is broken, for example, the state will always be the same as if the tape switch 7 was open regardless of whether the tape switch 7 was opened or closed. Even if the ray generator 5 comes into contact with the subject 3, it cannot be detected and the device continues to move, which is very dangerous.

(Problems to be Solved by the Invention) As explained above, the contact safety device with the conventional structure has no means to detect an abnormality when a disconnection occurs between the tape switch and the detection circuit, and the contact safety device There was a problem that it became inoperable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a contact safety device that detects even the above-mentioned disconnection state and eliminates the risk of malfunction or failure of the X-ray diagnostic device.

[Configuration of the Invention] (Means for Solving the Problems) The configuration of the present invention for solving the above problems includes a first resistor connected to a positive power supply, and a resistor connected in series with the first resistor. a second resistor connected, a switch connected in parallel to the second resistor, a first comparator circuit to which the voltage across the second resistor is applied to the positive input side, and a second a second comparator circuit to which the voltage applied to the resistor is applied to the negative input side; and a logic circuit which receives the output of the first comparator circuit and the output of the second comparator circuit and outputs an operation command or a stop command. It is characterized by having the following.

(Function) The voltage value applied to the resistor connected in parallel to the switch that detects the contact state with the subject etc. differs depending on the non-contact state, the contact state, and the disconnection state. The voltage value is input to the detection circuit, and the magnitude of the voltage value is compared with a predetermined value in the detection circuit. Based on the result, an operation signal is output if the non-contact state is detected, and an operation signal is output if the contact state or disconnection state is detected. If so, output a stop signal.

(Embodiment) FIG. 1 is a block diagram of an embodiment of the present invention. In this embodiment, a switch section 1 corresponding to the tape switch 7 in FIG.
detects whether the diagnostic device is in contact with the subject, etc. and outputs a signal according to the state, and the detection circuit section 2 determines the signal and outputs an operation signal or a stop signal, and the diagnostic device remain operational or deactivated. When a voltage V is applied to a circuit consisting of a resistor R1, a resistor RIO connected in series with the resistor R1, and a tape switch S1 connected in parallel with the resistor RIO, the resistor R
The voltage value VR applied to IO is expressed by the following equation.

In addition, diodes DI and D2 connected in parallel to the resistors R1 and RIO respectively connect the switch section 1 and the detection circuit section 2.
It works to prevent current from flowing backwards and destroying the circuit due to noise generated in the connection between the wire and the wire. The resistor R2 and capacitor C1 connected between the switch S1 and the input terminals of the comparator circuits ICI and IC2 prevent the comparator circuit from malfunctioning if there is a fluctuation in the signal magnitude when the signal changes rapidly. , is a low-pass filter that slows down signal changes to prevent this. In the comparator circuit ICI in the detection circuit section 2, a voltage VR is applied to the positive input side, and a voltage vU kept constant by the Zener diode D3 is applied to the negative input side. In the comparator circuit ICI, the calculation VR-VU is performed, and when VR-VU > 0 (7), C+V, VR-VU
When <0 (7), -V is output. A voltage VL kept constant by a Zener diode D4 is applied to the positive input side of the comparator circuit IC2 in the detection circuit section 2.
A voltage VR is applied to the negative input side. In the comparator circuit ICZ, the calculation VL-VR is performed, and VL -Vl
? When >0, outputs +V, and when VL -VR<0, outputs 1. Here, the range of possible values of voltages vU and VL is determined as follows.

In logic circuit IC3, comparator circuits IC1 and I
Although the output result of C2 is input, in order not to input a negative value to the logic circuit IC3, when the output of the comparator circuit ICI or IC2 is -V, the diode D5 or D6 is input.
becomes Ov.

In the logic circuit IC3, the input +V is “1”, Ov
is converted to "0", and outputs "O" when both inputs are "0", and outputs "1" when one of the inputs is "O" and the other is "1". When the output of IC3 is "1", a stop signal is output and the diagnostic device stops. When the output of IC3 is "O", an operation signal is output, and the diagnostic device maintains an operable state.

The operation of this embodiment will be explained below.

FIG. 1 shows a non-contact state in an embodiment of the present invention, that is, a state in which the diagnostic device is operating normally and is not in contact with a subject or the like.

In the non-contact state, the tape switch S1 in the switch section 1 is in an open state. At this time, the voltage value VR applied to the resistor RIO is expressed by equation (1), and is determined by the values of the two resistors R1 and RIO. Voltage value VR is applied to comparator circuits ICI and IC2, respectively, and compared with voltages vU and VL, respectively. From equation (2), VR<
VU, and the output of the comparator circuit ICI becomes 1.

Similarly, from equation (2), VR>VL, and the output of the comparator circuit IC2 becomes 1. Therefore, logic circuit IC
The two inputs of 3 are both “0” and the output is “O”
As a result, an operating signal is output and the device maintains an operable state.

FIG. 2 shows a contact state in the embodiment of the present invention, that is, a state in which the diagnostic device is in contact with a subject etc. due to malfunction or failure of the control device of the diagnostic device. In the contact state, the tape switch S1 in the switch section 1 is in a closed state. At this time, both ends of the resistor RIO are short-circuited, so in equation (1), it becomes equivalent to the resistance value R1O-0, and becomes the divided voltage value VR-0. Since VR<VLI, the output of the comparator circuit ICI becomes -V, and since VR<VL, the output of the comparator circuit IC2 becomes +V. Therefore, since "0" and "1" are input to the logic circuit IC3, the output is "
1'', and as a result, a stop signal is output and the device stops.

FIG. 3 shows a disconnection state in the embodiment of the present invention, that is, a state in which the connection between the switch section 1 and the detection circuit section 2 is disconnected as indicated by A in the figure.

In the disconnected state, no current flows through the resistor RIO, regardless of whether the tape switch S1 in the switch unit 1 is opened or closed. Therefore, in equation (1), it is equivalent to the resistance value RIO--, and becomes the divided voltage value VR-V.

Since VR>VU, the output of the comparator circuit ICI is +V,
Since VR>VL, the output of comparator circuit IC2(7) becomes a part. Therefore, since "1" and "0" are input to the logic circuit IC3, the output becomes "1", and as a result, a stop signal is output and the device stops.

As described above, the contact safety device according to the present invention can not only detect a contact state and a non-contact state, but also detect a disconnection state between the switch section and the detection circuit section.

Note that the present invention is not limited to the embodiments described above, and various modifications can be made without changing the gist thereof. For example, it is effective as a safety measure not only for X-ray diagnostic equipment but also for various equipment that uses a control device to move.

[Effects of the Invention] According to the present invention, a contact safety device for preventing the risk of contact with a subject, etc. when moving a part of the device in a medical diagnostic device detects a contact state and a non-contact state. Not only this, but also a disconnection state between the switch section and the detection circuit section can be detected, and the safety of the device can be improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention in a non-contact state;
Fig. 2 is a circuit diagram of the embodiment of the present invention in a contact state, Fig. 3 is a circuit diagram of the embodiment of the present invention in a disconnected state, and Fig. 4 is a circuit diagram of the embodiment of the present invention in a disconnected state.
The figure is a schematic diagram of an X-ray diagnostic device, Figure 5 is a schematic diagram showing the arrangement of a contact safety device in an X-ray generator, Figure 6 is an explanatory diagram showing the operating state of a tape switch, and Figure 7 is a conventional contact safety device. FIG. 2 is a circuit diagram showing the configuration of a safety device. R1, RIO...Resistor, Sl...Switch, IC
I, IC2... Comparator circuit, IC3... Logic circuit

Claims (1)

[Claims] a first resistor connected to a positive power source; a second resistor connected in series to the first resistor; a switch connected in parallel to the second resistor; a first comparator circuit to which a voltage across the resistor is applied to the positive input side; a second comparator circuit to which the voltage across the second resistor is applied to the negative input side; A contact safety device comprising: a logic circuit that inputs the output of the circuit and the output of the second comparator circuit and outputs an operation command or a stop command.