JPH065604U - X-ray equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To detect the size of the loaded cassette relatively easily. [Structure] A rotational speed of a motor 11 for driving a pair of sandwiching frames for sandwiching a loaded cassette is controlled by a potentiometer 31.
Detect with. The rotation speed detection signal from the potentiometer 31 is fetched at regular intervals, and the current value of the rotation speed detection signal is held in the current value hold circuit 33 and the previous value is held in the previous value hold circuit 34. When the comparison control circuit 36 detects that the current value and the previous value of the rotation speed detection signal match, the width determination circuit 37 determines the cassette size based on the rotation speed detection signal held in the current value hold circuit 33. To determine.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an X-ray imaging apparatus using a cassette, and more particularly to a technique for automatically detecting the size of a loaded cassette.

[0002]

[Prior art]

 Conventionally, cassettes of various sizes according to the region to be imaged are used in this type of X-ray imaging apparatus, so that the center of the cassette is made to coincide with the imaging position (center of X-ray imaging) or according to the size of the cassette. Since it is necessary to control the opening amount of the collimator to adjust the X-ray irradiation field, a mechanism for detecting the size of the loaded cassette is provided.

A conventional cassette size detection mechanism is generally configured as follows. This type of X-ray imaging apparatus has a transport mechanism for transporting the loaded cassette to the imaging position, and the loaded cassette has a mechanical sliding lever etc. on the moving stage provided in this transport mechanism. It is fixed by sandwiching it with. A magnet is attached to the slide lever, and a plurality of magnetic sensors corresponding to the type of cassette size are arranged in an array in the vicinity of the path of the magnet that moves as the slide lever moves. ing. When the loaded cassette is fixed by sandwiching the sliding lever, the size of the loaded cassette is detected depending on which magnetic sensor detects the magnetic force of the magnet and is in the ON state.

[0004]

[Problems to be solved by the device]

 However, according to the cassette size detecting mechanism as described above, a large number of magnetic sensors are required according to the type of cassette size, which causes a problem that the device configuration becomes complicated and the manufacturing cost increases. There is also a problem that a complicated work of attaching a large number of magnetic sensors to positions corresponding to each cassette size is involved.

The present invention has been made in view of such circumstances, and an object thereof is to provide an X-ray imaging apparatus capable of relatively easily detecting the size of the loaded cassette. There is.

[0006]

[Means for Solving the Problems]

 The present invention has the following configuration in order to achieve such an object. That is, the present invention is an X-ray imaging apparatus using a cassette, which drives a pair of sandwiching frames for sandwiching the loaded cassette from both sides and at least one of the sandwiching frames. A motor, a detection means for detecting the rotation speed of the motor, and a rotation speed holding function for fetching a detection signal from the detection means at regular intervals and holding the current value of the detection signal and the previous value of the detection signal Means for comparing the current value of the detection signal held in the rotation speed holding means with the previous value, and the comparison means for detecting that the current value of the detection signal matches the previous value. Thus, the discriminating means for discriminating the cassette size based on the value of the detection signal held in the rotation number holding means is provided.

[0007]

[Action]

 The operation of this device is as follows. When the cassette is loaded, at least one of the pair of sandwiching frames is driven. While the sandwich frame is moving, the motor rotation speed detected by the detection means changes over time, so the current value and the previous value of the rotation speed detection signal held by the rotation speed holding means are It does not match. When the cassette is sandwiched by the pair of sandwiching frames, the motor does not rotate any more. Therefore, the current value and the previous value of the rotation speed detection signal held by the rotation speed holding means match. At this time, the detection signal held by the rotation speed holding means has a value corresponding to the amount of movement of the sandwiching frame, that is, the size of the cassette. Then, the discriminating means discriminates the cassette size on the basis of the detection signal held in the rotational speed holding means by the coincidence signal from the comparing means.

[0008]

Embodiment An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a schematic configuration of an X-ray imaging apparatus using a cassette. A column 2 is erected on a bed 1 on which a subject (not shown) is lying down, and an X-ray tube 3 and a collimator 4 for adjusting the X-ray irradiation field are attached to the front end of the column 2. There is. A cassette transfer mechanism 5 is attached to the lower part of the bed 1, which is below the X-ray tube 3. Reference numeral 6 in the drawing is a cassette insertion hole for inserting a cassette.

The configuration of the cassette carrying mechanism 5 will be described below with reference to FIGS. 2 is a plan view of the cassette carrying mechanism 5, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. 4 is a sectional view taken along the line BB of FIG.

In FIG. 2, reference numeral 7 is a machine frame in which the cassette transport mechanism 5 is provided, and the upper side of FIG. 2 corresponds to the cassette insertion hole 6 side, and the reference numeral XC in the drawing is the center of X-ray imaging (X-ray imaging position). Hits. On the machine frame 7, a pair of guide rails 8a and 8b are arranged side by side from the cassette insertion hole 6 side toward the X-ray imaging position XC, and on the guide rails 8a and 8b are indicated by chain lines in the figure. A carriage 9 on which the illustrated cassette C is placed is slidably mounted.

On the carriage 9, there is provided a pair of sandwiching frames 10a and 10b that move in a direction orthogonal to the moving direction of the carriage 9 and sandwich the cassette C from both sides. On the machine frame 7, a drive pulley 12 that is driven to rotate forward and backward by a motor 11 and a driven pulley 13 are provided, and an endless belt 14 is installed on these pulleys 12 and 13. The belt 14 is also stretched over pulleys 15a, 15b, 15c provided on the carriage 9. A part of the belt 14 from the pulley 15a to the pulley 15b is connected to the sandwich frame 10b, and a part of the belt 14 from the pulley 15b to the pulley 15c is connected to the sandwich frame 10a.

On the back side of the carriage 9 (on the photographing position XC side), there is a receiving member 16 for receiving the inserted cassette C. The receiving member 16 holds the cassette C on the receiving member 16. For example, a micro switch 17 for detecting the contact is attached.

A stopper mechanism 18 for stopping the movement of the carriage 9 at the cassette loading position (position of the carriage 9 shown in FIG. 2) is provided on the machine frame 7. The stopper mechanism 18 includes a solenoid 19, an L-shaped lever 20 whose one end is connected to a rod of the solenoid 19 and is swingably driven, and a locking pin 21 attached to the other end of the lever 20. It is configured. Further, on the front side of the machine frame 7 (the cassette insertion hole 6 side), a reflection type optical sensor 22 for detecting the rear end of the cassette C when the cassette C is fed to the photographing position XC. It is installed.

FIG. 5 is a block diagram showing the configuration of a control system for detecting the size of the cassette C loaded in the cassette transport mechanism described above. The control system of the apparatus of the embodiment is roughly divided into a width detection circuit 30 for detecting the width of the cassette C, a length detection circuit 40 for detecting the length of the cassette C, and an apparatus control for controlling the X-ray imaging apparatus. The circuit 50 and the like are included.

The width detection circuit 30 includes a potentiometer 31 as a detection unit that detects the rotation speed of the motor 11, an A / D converter 32, a current value hold circuit 33 that holds the current rotation speed, and a previous value. A previous value hold circuit 34 for holding the number of revolutions, a pulse generation circuit 35 for giving the timing of taking in the number of revolutions, a comparison control circuit 36 as a comparison means for comparing the present value of the number of revolutions with the previous value, and a cassette. A width discriminating circuit 37 as a discriminating means for discriminating the width of C is included. Here, the detection means for detecting the number of rotations of the motor 11 is not limited to the potentiometer 31, and may be constituted by, for example, a rotary encoder and a counter. The present value hold circuit 33 and the previous value hold circuit 34 correspond to the rotation speed holding means in this invention.

The length detection circuit 40 detects the rear end of the cassette C by the optical sensor 22 and the reference value hold circuit 41 that holds the rotation speed when the current rotation speed and the previous rotation speed match. A difference circuit 42 for calculating the difference between the number of revolutions at that time and the number of revolutions held in the reference value hold circuit 41, and a length discriminating circuit 43 for discriminating the length of the cassette C based on the output of the difference circuit 42. including.

The operation of the X-ray imaging apparatus having the above-mentioned configuration will be described below. In the initial state (when the cassette C is loaded), the carriage 9 is in the cassette loading position as shown in FIG. 2, and the solenoid 19 of the stopper mechanism 18 pushes the lever 20 to move the carriage 9 by the locking pin 21. Is regulated. Further, the sandwiching frames 10a and 10b are in the preset open position (initial position). In this state, the operator inserts the cassette C through the cassette insertion hole 6. When the cassette C comes into contact with the receiving member 16, the micro switch 17 detects it and sends a cassette insertion signal a to the device control circuit 50. Based on this, the device control circuit 50 sends a motor drive signal b for driving the motor 11 in the forward direction (clockwise in FIG. 2) to the motor drive circuit 23. As a result, the belt 14 is driven, the sandwiching frames 10a and 10b move toward each other, and the cassette C is sandwiched from both sides, whereby the cassette C is positioned.

The width detection circuit 30 detects the width of the cassette C as follows in accordance with the holding operation of the holding frames 10a and 10b described above. That is, the potentiometer 31 detects the number of rotations of the sandwiching frames 10a and 10b while they are moving, that is, when the motor 11 rotates. The rotation speed detection signal output from the potentiometer 31 is converted into a digital signal by the A / D converter 32 and then sent to the current value hold circuit 33. The current value hold circuit 33 holds the rotation speed detection signal for each timing (for example, a timing pulse every 0.1 seconds) given from the pulse generation circuit 35. The comparison control circuit 36 receives the current rotation speed detection signal held in the current value hold circuit 33 and the previous time value held in the previous value hold circuit 34 at the same timing given from the pulse generation circuit 35. Compare with the captured rotation speed detection signal. When the motor drive signal b is OFF (that is, the initial state where the motor 11 is not rotating), the previous value hold circuit 34 is reset by the reset signal c from the comparison control circuit 36.

When both the rotation speed detection signals of the current value hold circuit 33 and the previous value hold circuit 34 do not match, the comparison control circuit 36 sends the hold signal d 1 to the previous value hold circuit 34. As a result, the rotation speed detection signal held in the current value hold circuit 33 is held in the previous value hold circuit 34. Then, at the next timing pulse from the pulse generation circuit 35, a new rotation speed detection signal is held in the present value hold circuit 33, and the rotation speed detection signal and the previous rotation speed held in the previous value hold circuit 34 are held. The detection signal is compared by the comparison control circuit 36. Thereafter, in the same manner, the current value and the previous value of the rotation speed detection signal of the motor 11 fetched at regular intervals are compared. While the sandwiching frames 10a and 10b are moving, that is, while the cassette C is not sandwiched, the rotation speed of the motor 11 detected by the potentiometer 31 continues to change, and the current value hold circuit 33 and the previous value hold circuit are held. Since the contents of the circuit 34 do not match, their contents are sequentially updated as described above.

When the sandwiching frames 10a and 10b sandwich the cassette C, the motor 11 does not rotate any more, so that the output signal (rotation speed detection signal) of the potentiometer 31 does not change. As a result, the current value of the rotation speed detection signal held in the current value hold circuit 33 and the previous value of the rotation speed detection signal held in the previous value hold circuit 34 match, and the comparison control circuit 36 outputs the match signal e. Is output. Based on this coincidence signal e, the width determination circuit 37 takes in the rotation speed detection signal held in the current value hold circuit 33. As shown in FIG. 2, this rotation speed detection signal corresponds to the moving amount W until the sandwiching frames 10a, 10b in the initial position sandwich the cassette C. Since the movement amount W of the sandwich frames 10a and 10b changes according to the width of the cassette C, the movement amount W, that is, the rotation speed detection signal when the coincidence signal e is output, depends on the width of the cassette C. It becomes the value. The width discriminating circuit 37 has a table of rotation speed detection signals associated with the width of the cassette C, and by referring to this table, the width of the cassette C loaded is checked based on the rotation speed detection signals taken in. Determine the width. The determined width detection signal f is given to the device control circuit 50. With the above operation, the detection of the width size of the cassette C is completed.

The device control circuit 50, which is given the coincidence signal e from the comparison control circuit 36, judges that the cassette C has been positioned and sandwiched by the sandwiching frames 10a and 10b, and sends the drive signal g to the solenoid 19. , The stopper mechanism 18 is released. As a result, the motor 11 rotates again, and the carriage 9 moves in the shooting position XC direction with the belt 14 locking the pulley 15a on the carriage 9. The coincidence signal e is also given to the reference value hold circuit 41 of the length detection circuit 40. As a result, the reference value hold circuit 41 holds the rotation number detection signal (hereinafter referred to as the reference detection signal) held in the current value hold circuit 33 at that time.

While the stopper mechanism 18 is released and the carriage 9 is moving, the rotation speed detection signal of the potentiometer 31 changes, and its value is held in the current value hold circuit 33 at regular intervals. Then, the rotation speed detection signal is sent to the difference circuit 42 of the length detection circuit 40. When the optical sensor 22 detects the rear end of the cassette C while the carriage 9 is moving in the photographing position XC direction, a rear end detection signal h is sent from the optical sensor 22 to the device control circuit 50. As a result, the device control circuit 50 outputs the timing signal i to the difference circuit 42 and the length determination circuit 43. As a result, the difference circuit 42 receives the reference detection signal (that is, the rotation speed detection signal at the time when the carriage 9 starts moving) held in the reference value hold circuit 41 and the optical sensor 22 after the cassette C. A difference signal from the rotation speed detection signal when the end is detected is output. This differential signal corresponds to the length L from the optical sensor 22 to the rear end of the cassette C, as shown in FIG. Since the length L changes according to the length of the loaded cassette C, the length of the cassette C can be determined based on the difference signal. The length discriminating circuit 43 is provided with a table in which the difference signal and the length of the cassette C are associated with each other. By referring to this table, the table is loaded based on the difference signal given from the difference circuit 42. Then, the length of the cassette C is determined. The determined length detection signal j is given to the device control circuit 50. By the above operation, the detection of the length size of the cassette C is completed.

As described above, if the size of the cassette C is known, the rotation speed of the motor 11 required to move the center of the cassette C, which has already been positioned, to the photographing position XC can be derived. . Specifically, the device control circuit 50 is provided with, as a table, the number of rotations required to move the center of each cassette C to the photographing position XC according to the cassette size, and from the A / D converter 32, When the input rotation speed detection signal matches the rotation speed corresponding to the detected cassette size, the motor drive signal b is turned off to stop the motor 11. As a result, the center of the cassette C is automatically set at the photographing position XC.

When the cassette C is set at the imaging position XC, the device control circuit 50 controls the collimator 4 shown in FIG. 1 so that an X-ray irradiation field corresponding to the detected cassette size can be obtained. After that, an X-ray image of the subject is taken. When the photographing is completed, the device control circuit 50 reverses the motor 11 to return the carriage 9 to the cassette loading position and restores the interval between the sandwiching frames 10a and 10b to the initial state.

In the above-described embodiment, the sandwiching frames 10a and 10b are configured to move together, but one sandwiching frame is fixedly installed on the carriage, and the other sandwiching frame is configured to be movable. May be. In this case, the cassette is positioned with reference to one fixedly installed sandwiching frame, and the width of the cassette can be determined by detecting the amount of movement of the other sandwiching frame.

Further, in the above-described embodiment, the width of the loaded cassette C is detected based on the movement amount of the sandwiching frames 10a and 10b, but a pair of similar sandwiching frames that move in the moving direction of the carriage 9 is detected. The cassette C may be individually provided, and the cassette C may be sandwiched by the sandwiching frame from the longitudinal direction, and the length of the cassette C may be detected based on the movement amount of the sandwiching frame at that time.

Further, in the embodiment, the cassette size is detected by a so-called hardware configuration, but a similar configuration can be realized by software using a microcomputer.

[0028]

[Effect of device]

 As is clear from the above description, according to the present invention, the pair of sandwiching frames that sandwich the loaded cassette from both sides are driven by the motor to detect the rotation speed of the motor, and the rotation speed detection signal changes. The size of the cassette is determined based on the value of the rotation speed detection signal when it is no longer used, that is, the amount of movement of the sandwiched frame. Since it is not necessary to adjust the position of each magnetic sensor and attach them, various cassette sizes can be identified relatively easily.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an X-ray imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a cassette carrying mechanism which is a main part of the embodiment apparatus.

FIG. 3 is a sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along the line BB of FIG.

FIG. 5 is a block diagram showing a schematic configuration of a cassette size detection unit of the embodiment apparatus.

[Explanation of symbols]

 5 ... Cassette transport mechanism 10a, 10b ... Nipple frame 11 ... Motor 30 ... Width detection circuit 31 ... Potentiometer (rotation speed detection means) 33 ... Current value hold circuit (rotation speed holding means) 34 ... Previous value hold circuit (rotation speed holding) Means) 36 ... Comparison control circuit (comparison means) 37 ... Width discrimination circuit (discrimination means) 40 ... Length detection circuit 50 ... Device control circuit

Claims (1)

[Scope of utility model registration request] 1. An X-ray imaging apparatus using a cassette, comprising a pair of sandwiching frames for sandwiching and sandwiching the loaded cassette from both sides, and a motor for driving at least one of the sandwiching frames. Detection means for detecting the rotation speed of the motor; rotation speed holding means for holding a current value of the detection signal and a previous value of the detection signal by taking in a detection signal from the detection means at regular intervals; The comparison means for comparing the current value and the previous value of the detection signal held in the number holding means, and the comparison means detects that the current value and the previous value of the detection signal match, thereby retaining the rotation speed. An X-ray imaging apparatus comprising: a discriminating means for discriminating a cassette size based on a value of a detection signal held by the means.