Radiographic imaging device

Abstract

The present invention provides a radiation imaging apparatus that can change the load of the manual operation force based on the arm. The radiation imaging apparatus (10) includes: an irradiation unit (18) that irradiates radiation; an arm (12) that can hold the irradiation unit (18) and the image receiving unit (20) in an opposed posture; a first rotation mechanism that rotates the arm (12); and a friction mechanism (44) that can switch between a first state in which a frictional force in a direction opposite to the rotation direction of the arm (12) acts on the arm (12) and a second state in which the frictional force acting on the arm (12) is reduced compared to the first state.

Description

Technical Field

[0001] The present invention relates to a radiation imaging apparatus. Background Art

[0002] There is known a radiation imaging apparatus (X-ray apparatus) having an arm. The arm has two ends, and at one end, an irradiation unit (X-ray tube) that irradiates radiation is provided, and at the other end, an image receiving unit (image receiving device) that receives the radiation irradiated from the irradiation unit and transmitted through a subject is provided. The arm is rotatably supported on the main body of the radiation imaging apparatus, and is configured such that by rotating the arm, it can be positioned in any posture around the subject while the irradiation unit and the image receiving unit maintain their relative positions. Further, in the radiation imaging apparatus described in Patent Document 1, the rotation operation of the arm can be performed by manual operation.

[0003] Patent Document 1: Japanese Patent Laid-Open No. 06-070918

[0004] In the case of manually operating the arm, the load of the operating force is sometimes preferably small and sometimes preferably large. For example, when considering the use of a radiation imaging apparatus during surgery, during the positioning stage before surgery, the load of the operating force of the arm is preferably small, and after the start of surgery, the arm should preferably not rotate inadvertently due to human contact or the like.

[0005] In particular, in the case of an arm that holds both the irradiation unit and the image receiving unit, compared to an arm that holds only the irradiation unit, the weight is heavier, and thus it is necessary to reduce the load of the operating force based on manual operation. On the other hand, if the load of the operating force is continuously reduced, inadvertent rotation is likely to occur, which is not preferable. In Patent Document 1, such problems and countermeasures are neither disclosed nor suggested. Therefore, countermeasures for solving such problems are needed. Summary of the Invention

[0006] An object of the technology related to the present invention is to provide a radiation imaging apparatus capable of changing the load of the manual operating force based on the arm.

[0007] The radiation imaging apparatus according to the first aspect of the present invention includes: an irradiation unit that irradiates radiation; an arm that can hold the irradiation unit and an image receiving unit that receives the radiation irradiated from the irradiation unit and transmitted through a subject in an opposed posture; a support unit that supports the arm; a displacement mechanism that displaces the arm relative to the support unit; and a friction mechanism that can switch between a first state in which a frictional force in a direction opposite to the displacement direction of the arm acts on the arm and a second state in which the frictional force acting on the arm is smaller than that in the first state.

[0008] According to the above structure, the radiation imaging device includes: a displacement mechanism that displaces the arm; and a friction mechanism that can switch between a first state in which a frictional force in a direction opposite to the displacement direction of the arm acts on the arm and a second state in which the frictional force acting on the arm is reduced compared to the first state. Therefore, the load based on the manual operation force of the arm can be changed by switching between the first state and the second state of the friction mechanism.

[0009] In the radiation imaging device according to the second aspect of the present invention, in the radiation imaging device according to the first aspect, an operation unit is provided that switches between the first state and the second state of the friction mechanism.

[0010] According to the above structure, the operator can arbitrarily switch the frictional force. For example, before the operation, the frictional force is reduced to perform positioning with a slight force, and during the operation, the frictional force can be increased to prevent accidental external forces such as the operator colliding with the arm from being applied to the arm and causing the arm to rotate inadvertently.

[0011] In the radiation imaging device according to the third aspect of the present invention, in the radiation imaging device according to the first aspect or the second aspect, the displacement operation of the arm can be performed only by manual operation.

[0012] According to the above structure, the displacement operation of the arm can be performed only by manual operation without relying on electricity. Therefore, the entire radiation imaging device can be made small and lightweight. And in the mechanism for displacing the arm by electricity, usually the radiation imaging device itself is a large device, and in a large device, the control of the operation force of the arm is usually achieved by a complex mechanism such as an electric mechanism.

[0013] Among them, in the friction mechanism related to the technology of the present invention, even when the displacement operation of the arm is performed only by manual operation to make the device small and lightweight, the operation force of the arm can be switched with a relatively simple structure. Therefore, the technology of the present invention is particularly effective for a small and lightweight device that performs the displacement operation of the arm only by manual operation.

[0014] In the radiation imaging device according to the fourth aspect of the present invention, in the radiation imaging device according to any one of the first aspect to the third aspect, the displacement mechanism is a rotation mechanism that rotates the arm.

[0015] According to the above structure, compared with the operation of sliding the arm in the horizontal direction, the rotation operation of rotating the arm is more effective when a friction mechanism capable of switching the frictional force is combined with the rotation mechanism because a load is applied.

[0016] In the radiation imaging device according to the fifth aspect of the present invention, in the radiation imaging device according to the fourth aspect, the image receiving unit can be detachably mounted on the arm.

[0017] According to the above structure, when the arm rotates, if the image receiving unit is detachable, the weight balance changes greatly when the image receiving unit is disassembled, so that it is easy to cause inadvertent rotation. Therefore, for example, when the image receiving unit is disassembled, inadvertent rotation can be suppressed by increasing the friction force in advance.

[0018] The radiation imaging device involved in the 6th embodiment of the present invention is provided with: a loading and unloading detection unit for detecting whether the image receiving unit is removed from the arm; and a control unit for performing the following control, namely, in the loading and unloading detection unit, when it is detected that the image receiving unit is removed from the arm, the friction mechanism is set to the first state; and when it is detected that the image receiving unit is installed on the arm, the friction mechanism is set to the second state.

[0019] If the image receiving unit is removed from the arm, the weight balance of the arm changes, sometimes causing the arm to rotate unintentionally. According to the above structure, by increasing the friction force in conjunction with the removal of the image receiving unit, the arm can be prevented from rotating unintentionally even when the image receiving unit is removed.

[0020] A radiation imaging device according to a seventh aspect of the present invention is the radiation imaging device according to the sixth aspect, wherein the friction force in the first state is larger than the maximum weight of the image receiving section that can be attached to the arm.

[0021] According to the above configuration, the friction force in the first state is larger than the weight of the image receiving unit. Therefore, the change in the weight balance of the arm when the image receiving unit is removed can be absorbed by the friction force, thereby further suppressing the arm from rotating unintentionally.

[0022] A radiation imaging device according to an eighth aspect of the present invention is the radiation imaging device according to any one of the fourth to seventh aspects, further comprising an electromagnetic brake that locks the rotation of the arm by the rotation mechanism.

[0023] According to the above configuration, since the electromagnetic brake for locking the rotation of the arm is provided in addition to the friction mechanism, the rotation of the arm can be prohibited as needed by locking the rotation of the arm in advance with the electromagnetic brake.

[0024] In the radiation imaging device involved in the 9th mode of the present invention, in the radiation imaging device involved in any one of the 4th to 8th modes, the rotating mechanism has a rotating shaft that rotates with the rotation of the arm, and the friction mechanism comprises: a friction shaft; a friction force generating part that is installed on the friction shaft and generates friction force; and a clutch that switches between the first state and the second state by switching the connection and non-connection between the rotating shaft and the friction shaft.

[0025] According to the above structure, compared with the case where the rotating mechanism and the friction mechanism are separately and independently formed, it is possible to make each mechanism compact by linking the constituent elements of the rotating mechanism and the constituent elements of the friction mechanism.

[0026] In the radiation imaging apparatus according to the tenth aspect of the present invention, in the radiation imaging apparatus according to the eighth aspect or the ninth aspect that cites the eighth aspect, the rotating mechanism has a rotating shaft that rotates as the arm rotates, and the electromagnetic brake is connected to the rotating shaft.

[0027] According to the above structure, compared with the case where the rotating mechanism and the electromagnetic brake are separately and independently formed, it is possible to make each mechanism compact by connecting the constituent elements of the rotating mechanism and the electromagnetic brake.

[0028] In the radiation imaging apparatus according to the eleventh aspect of the present invention, in the radiation imaging apparatus according to the ninth aspect or the tenth aspect, the arm is formed in an arc shape in a side view, and the rotating mechanism includes a first rotating mechanism. The first rotating mechanism includes: a track portion provided on the support portion and movably supporting the arm along the arc shape; a fitting portion formed on the outer peripheral portion of the arm and fitted to the track portion; and a first rotating shaft serving as a rotating axis. The arm can perform orbital rotation with the center of the arc shape as the rotation center by moving relative to the track portion.

[0029] According to the above structure, since the arm can rotate along the arc-shaped track, it is possible to rotate the irradiation unit and the image receiving unit around the body axis of the subject.

[0030] In the radiation imaging apparatus according to the twelfth aspect of the present invention, in the radiation imaging apparatus according to the eleventh aspect that cites the ninth aspect, the rotating mechanism further has a conveyor belt. One end of the conveyor belt is fixed to the end side of the arm where the irradiation unit is provided, and the other end is fixed to the end side of the arm where the image receiving unit is provided, and the conveyor belt is wound around the first rotating shaft.

[0031] According to the above structure, even during orbital rotation, it is possible to link the constituent elements of the rotating mechanism and the constituent elements of the friction mechanism, and compared with the case where the rotating mechanism and the friction mechanism are separately and independently formed, it is possible to make each mechanism compact.

[0032] Moreover, as a modification example of the rotating mechanism for orbital rotation, a rack and pinion method or a method of combining a chain and a sprocket can also be considered instead of the conveyor belt. However, by using the conveyor belt, it is possible to achieve weight reduction compared with them.

[0033] In the radiation imaging apparatus according to the 13th aspect of the present invention, in the radiation imaging apparatus according to any one of the 9th to 12th aspects, the rotation mechanism includes a second rotation mechanism, and the second rotation mechanism includes: a second rotation axis as a rotation axis, one end of which is fixed to the arm; and a bearing portion provided on the support portion, and the arm can reverse the positions of the irradiation portion and the image receiving portion with respect to the subject by rotating around the second rotation axis with respect to the bearing portion.

[0034] According to the above structure, since the arm is configured to be rotatable around the rotation axis, it is possible to switch between an outer tube posture in which the irradiation portion is disposed above the image receiving portion and an inner tube posture in which the irradiation portion is disposed below the image receiving portion.

[0035] In the radiation imaging apparatus according to the 14th aspect of the present invention, in the radiation imaging apparatus according to any one of the 1st to 13th aspects, an operation handle is provided, and the operation handle is separately provided from the arm and can input an operation force for displacing the arm with respect to the displacement mechanism by manual operation.

[0036] According to the above structure, the arm can be operated by the operation handle without directly operating the arm itself. Moreover, since the arm is displaced via the displacement mechanism, it is easier to adjust the displacement amount of the arm compared to directly operating the arm itself.

[0037] That is, regarding the relationship between the operation amount of the operation handle and the displacement amount of the arm, for example, it can be adjusted by setting the tooth ratio inside the displacement mechanism. Therefore, it is relatively simple to set the displacement amount of the arm to be smaller than the displacement amount of the operation handle. With such an operation handle, it is easy to finely adjust the displacement amount of the arm.

[0038] Moreover, the arm holding the irradiation portion and the image receiving portion is generally used during surgery. By separately providing the operation handle from such an arm, it is possible to separate the operation part operated by the surgeon from the operation part operated by the assistant. Therefore, it is also possible to use methods such as having the assistant rotate the arm to avoid the operation part being contaminated by contact with the surgeon.

[0039] Advantages of the Invention

[0040] According to the technology of the present invention, it is possible to change the load based on the manual operation force of the arm. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is an overall perspective view showing the radiation imaging apparatus according to the first embodiment.

[0042] Figure 2A It is a side view of the radiation imaging apparatus according to the first embodiment.

[0043] Figure 2B It is shown to makeFigure 2A A side view of the arm of the radiographic imaging apparatus shown in a state of rotating in the direction of arrow M1.

[0044] Figure 2C It represents making Figure 2A A side view of the arm of the radiographic imaging apparatus shown in a state of rotating in the direction of arrow M2.

[0045] Figure 3A A front view of the radiographic imaging apparatus according to the first embodiment.

[0046] Figure 3B It represents making Figure 3A A front view of the arm of the radiographic imaging apparatus shown in a state of rotating in the direction of arrow N1.

[0047] Figure 3C It represents making Figure 3A A front view of the arm of the radiographic imaging apparatus shown in a state of rotating 180° in the direction of arrow N2.

[0048] Figure 4 An overall side view of the friction mechanism of the radiographic imaging apparatus according to the first embodiment.

[0049] Figure 5 It is Figure 4 A cross-sectional view taken along line A-A in

[0050] Figure 6 A perspective view of the friction mechanism of the radiographic imaging apparatus according to the first embodiment.

[0051] Figure 7 It is Figure 6 A plan view of the friction mechanism shown in

[0052] Figure 8A A partial perspective view of the image receiving portion of the radiographic imaging apparatus according to the second embodiment.

[0053] Figure 8B It is Figure 8A A cross-sectional view of the image receiving portion shown in

[0054] Figure 9 A perspective view of the friction mechanism and electromagnetic brake of the radiographic imaging apparatus according to the second embodiment.

[0055] Figure 10 It is Figure 9 A plan view of the friction mechanism and electromagnetic brake shown in

[0056] Figure 11 A block diagram showing the functional structure of the control portion of the radiographic imaging apparatus according to the second embodiment.

[0057] Figure 12 It is a flowchart showing the processing steps of the control unit of the radiation imaging device according to the second embodiment.

[0058] Figure 13 It is an overall side view of the friction mechanism of the radiation imaging device according to the third embodiment.

[0059] Figure 14 It is a perspective view of the friction mechanism of the radiation imaging device according to the third embodiment.

[0060] Figure 15 is Figure 14 a plan view of the friction mechanism shown.

[0061] Figure 16 It is a block diagram showing the functional structure of the control unit of the radiation imaging device according to the third embodiment.

[0062] Figure 17 It is a perspective view of the operation handle of the radiation imaging device according to the modification.

[0063] Figure 18 is Figure 17 a plan view of the operation handle shown.

[0064] Figure 19 It is a side view of the displacement mechanism of the radiation imaging device according to the modification.

[0065] Figure 20A It is a partial perspective view of the image receiving unit of the radiation imaging device according to the modification.

[0066] Figure 20B is Figure 20A a cross-sectional view of the image receiving unit shown.

[0067] Symbol description:

[0068] 10, 100, 200 - Radiation imaging device, 12 - Arm, 14 - Connecting portion, 16 - Main body portion, 18 - Irradiation portion, 20, 102, 246 - Image receiving portion, 20A - Image receiving surface, 21 - First rotation mechanism, 22A - Fitting portion, 22B - Rail portion, 23 - Second rotation mechanism, 24 - Support shaft, 25, 50, 68 - Bearing portion, 26 - Caster, 28, 126, 222 - Control portion, 30 - Operation panel, 31 - Radiation source, 32 - Radiation tube, 34 - Irradiation field limiter, 34A - Irradiation opening, 36 - Rotation shaft, 38 - Mounting plate, 40 - Cable, 42 - Hollow portion, 42A - Groove, 44, 202 - Friction mechanism, 46 - Conveyor belt, 46A, 242A, 244A - Teeth, 48 - Pulley shaft, 52, 216 - Frame, 54 - Pulley, 54A - Groove, 56 - Idler pulley, 58 - First gear, 60 - Second gear, 60A, 70A, 84A - Shaft hole, 62, 210 - Friction shaft, 64, 212 - Friction force generating portion, 66, 214 - Clutch, 70 - Side plate, 72A, 72B - Friction plate, 74 - Biasing portion, 76 - Restricting plate, 78 - Disc spring unit, 78A - Disc spring, 80 - Buffer plate, 82 - Nut, 84, 124A, 204A, 218, 212A - Housing, 86, 220 - Shaft fixing portion, 104 - Base, 106 - Fitting convex portion, 108, 252 - Fitting concave portion, 110 - Positioning pin, 112 - Pin hole, 114 - Through hole, 116 - Solenoid, 116A - Movable iron core, 118 - Insertion hole, 120 - Photo sensor (an example of the loading / unloading detection portion), 122A, 122B - Terminal, 124, 204 - Electromagnetic brake, 206 - Third gear, 208 - Fourth gear, 224 - Operation handle, 226 - Gripping portion, 228 - Handle shaft, 229 - Side wall, 230 - Switching mechanism, 232 - Gear, 234 - Biasing member, 236 - Spacer, 240 - Sliding mechanism, 242 - Rack, 244 - Pinion, 248 - Detector, 250 - Receiving portion, 254 - Receiving concave portion, 256 - Photo sensor, H - Subject, S - Bed. Detailed implementation manners

[0069] Hereinafter, the radiation imaging device according to the first to third embodiments of the present invention will be described in sequence with reference to the accompanying drawings. In the drawings, arrow X indicates the front - rear direction of the radiation imaging device, arrow Y indicates the width direction of the radiation imaging device, and arrow Z indicates the vertical direction.

[0070] <First Embodiment>

[0071] First, with reference to Figures 1-7 the radiation imaging device according to the first embodiment of the present invention will be described.

[0072] (Overall Structure of the Radiographic Imaging Apparatus)

[0073] Figure 1 The radiographic imaging apparatus 10 of the present embodiment shown is an apparatus for photographing a radiographic image of a subject H. The radiographic imaging apparatus 10 can, for example, perform moving image photography and still image photography of the subject H. The moving image photography is performed, for example, when the treatment target part of the subject H is displayed in the form of a moving image during surgery (also referred to as fluoroscopic photography, etc.). In the moving image photography, for example, the moving image of the subject H is displayed on a monitor (not shown) provided separately from the radiographic imaging apparatus 10. Of course, the data of the photographed moving image can also be stored in the memory of the radiographic imaging apparatus 10. Also, in the case of still image photography, the photographed still image can be displayed on the monitor or stored in the memory in the radiographic imaging apparatus 10.

[0074] As Figure 1 shown, the radiographic imaging apparatus 10 has an arm 12 whose side shape is set to a C shape (arc shape) (referred to as a C-arm, etc.) and a main body 16 to which a connecting portion 14 is attached. In the following, the side where the arm 12 is provided in the radiographic imaging apparatus 10 is defined as the front of the radiographic imaging apparatus 10, and the side where the main body 16 is provided is defined as the rear of the radiographic imaging apparatus 10.

[0075] (Structure of the Arm)

[0076] The arm 12 has two end portions. An irradiation portion 18 is provided at one end portion of the arm 12, and an image receiving portion 20 is provided at the other end portion. The arm 12 can hold the irradiation portion 18 and the image receiving portion 20 in an opposed posture. An interval is ensured between the irradiation portion 18 and the image receiving portion 20 so that the subject H and the bed S on which the subject H lies supine can be inserted. In the following, in the side view of the arm 12 (the direction observed from the Y direction in Figure 1 ), with the arm 12 as a reference, the direction in which the irradiation portion 18 and the image receiving portion 20 are provided is sometimes referred to as the front of the arm 12, and the side of the arm 12 is referred to as the rear of the arm 12.

[0077] The arm 12 can be rotated manually. Specifically, as Figure 2A shown, the arm 12 can orbitally rotate relative to the connecting portion 14 about an axis M (an axis parallel to the Y axis) by a first rotation mechanism 21 as an example of a displacement mechanism. And the arm 12 can axially rotate relative to the main body 16 about an axis N (an axis parallel to the X axis) by a second rotation mechanism 23 as an example of a displacement mechanism. In the present embodiment, the connecting portion 14 or the main body 16 corresponds to a "support portion" that supports the arm 12.

[0078] The first rotating mechanism 21 includes an orbital part 22B provided in the connecting part 14 and a fitting part 22A formed on the outer peripheral surface of the arm 12 and fitted to the orbital part 22B. In addition, the first rotating mechanism 21 further includes a pulley shaft 48 serving as a first rotating shaft described later and a conveyor belt 46.

[0079] The fitting part 22A has an arc shape along the shape of the arm 12. And the orbital part 22B has an arc shape with the same radius as the arc of the arm 12 and supports the arm 12 movably along the arc shape. As Figure 5 shown, the orbital part 22B is, for example, in a groove shape, and the convex fitting part 22A is fitted therein. In addition, a roller (not shown) for assisting the fitting part 22A to slide relative to the orbital part 22B is inserted between the orbital part 22B and the fitting part 22A.

[0080] By the fitting part 22A formed on the arm 12 sliding along the orbital part 22B formed in the connecting part 14, the arm 12 is configured to be capable of orbiting and rotating relative to the connecting part 14 and the main body part 16 about the axis M at the center of the arc of the arm 12.

[0081] That is, as Figure 2B and Figure 2C shown, it is configured to be capable of orbiting the arm 12 about the axis M in the direction of arrow M1 ( Figure 2B counterclockwise direction in Figure 2C ) and the direction of arrow M2 ( Figure 1 clockwise direction in

[0082] such a way that the irradiation part 18 and the image receiving part 20 provided at both ends of the arm 12 can rotate around the body axis (axis parallel to the Y axis) of the subject H (refer to Figure 2A ).

[0083] As the support shaft 24 rotates relative to the bearing part 25 about the axis N, as Figures 3A-3C shown, it is configured to be capable of axial rotation of the arm 12 and the connecting part 14 relative to the main body part 16 about the axis N of the support shaft 24.

[0084] That is, as Figure 3B and Figure 3C shown, it is configured to be capable of orbiting the arm 12 about the axis N in the direction of arrow N1 ( Figure 3B counterclockwise direction in Figure 3Crotates about the (clockwise in the figure) axis. As a result, the irradiation unit 18 and the image receiving unit 20 provided at both ends of the arm 12 can be reversed in position in the vertical direction (Z-axis direction) with respect to the subject H (reference Figure 1 )

[0085] Among them, Figure 3A the posture of the arm 12 in which the irradiation unit 18 shown in the figure is arranged at a position higher than the image receiving unit 20 is called an outer tube posture because the radiation tube 32 (reference Figure 1 ) included in the irradiation unit 18 is located above the subject H. On the other hand, Figure 3C the posture of the arm 12 in which the irradiation unit 18 shown in the figure is arranged at a position lower than the image receiving unit 20 is called a lower tube posture because the radiation tube 32 is located below the subject H.

[0086] Compared with the lower tube posture, the outer tube posture can increase the distance between the irradiation unit 18 and the subject H (reference Figure 1 ), so a relatively wide area can be photographed. Therefore, the outer tube posture is mainly used when photographing a still image of the subject H. On the other hand, in the lower tube posture, part of the radiation emitted from the irradiation unit 18 is shielded by the bed S or the like, so the radiation dose to the surgeon or operator (not shown) around the subject H (reference Figure 1 ) can be reduced. Therefore, the lower tube posture is used when continuously irradiating radiation to photograph a moving image of the subject H.

[0087] (Structure of the main body)

[0088] As Figure 1 shown, a plurality of casters 26 are installed at the lower part of the main body 16 of the radiation imaging device 10, and it is configured to be able to travel in, for example, an operating room or a ward by being pushed by an operator's hand. That is, the radiation imaging device 10 of the present embodiment is configured to be mobile.

[0089] In addition, the main body 16 has a control unit 28 that controls each part of the radiation imaging device 10 such as the irradiation unit 18 and, for example, a touch panel type operation panel 30. In addition to this, the main body 16 includes various switches (not shown) such as a power switch of the radiation imaging device 10, a power circuit that supplies power to each part of the radiation imaging device 10, and a battery.

[0090] The operation panel 30 functions as an operation unit for operating each part by inputting an operation command to each part of the radiation imaging device 10, and functions as a display unit for displaying various information such as a warning message and a radiation image output from the image receiving unit 20.

[0091] (Structure of the control unit)

[0092] The control unit 28 controls the tube voltage, tube current, radiation irradiation time, etc. of the X-ray tube 32 by sending control signals to the X-ray tube 32 of the irradiation unit 18 described later. The energy of the radiation is controlled by controlling the tube voltage, and the dose of the radiation is controlled by controlling the tube current and irradiation time. In fact, a high voltage is applied to the X-ray tube 32, so the control unit 28 controls the X-ray tube 32 through a high voltage generating device (not shown). When performing photography, photographic conditions including tube voltage, tube current, irradiation time, etc. are set through the operation panel 30. The control unit 28 operates the irradiation unit 18 according to the set photographic conditions.

[0093] The control unit 28 can perform moving image photography of the subject H by causing the irradiation unit 18 to perform irradiation for moving image photography in which radiation is continuously irradiated from the irradiation unit 18. When performing moving image photography, the control unit 28 operates the detector of the image receiving unit 20 described later in synchronization with the irradiation for moving image photography of the irradiation unit 18. In the case of performing moving image photography, as the photographic conditions, the irradiation time is basically not set, and commands for starting and ending moving image photography are given through the operation panel 30. When a command for starting moving image photography is input, the control unit 28 starts irradiating radiation from the irradiation unit 18 under the preset photographic conditions.

[0094] In moving image photography, during irradiation for moving image photography, the detector repeatedly performs image detection operations at a preset frame rate. The images output by the detector are sent to the control unit 28. The control unit 28 sequentially outputs the received images to a monitor (not shown). Thereby, a moving image of the subject H is displayed on the monitor.

[0095] Moreover, the control unit 28 can perform still image photography of the subject H by causing the irradiation unit 18 to perform irradiation for still image photography in which radiation is irradiated from the irradiation unit 18 in a shorter time than the irradiation for moving image photography.

[0096] In still image photography, the control unit 28 operates the detector of the image receiving unit 20 in synchronization with the irradiation timing of the irradiation for still image photography of the irradiation unit 18. For example, a command for still image photography is given through an irradiation switch (not shown) connected to the control unit 28. In the case of performing still image photography, the irradiation time is, for example, an amount of time from several tens of milliseconds to several hundreds of milliseconds. When a command for still image photography is input, the control unit 28 operates the irradiation unit 18 according to the preset photographic conditions. In the case of performing still image photography, the irradiation time is set in the photographic conditions, so the irradiation of the irradiation unit 18 ends when the set irradiation time has elapsed.

[0097] When the irradiation ends, the detector starts to output the detected image. The image output by the detector is sent to the control unit 28. The control unit 28 stores the data of the still image in a memory (not shown). Moreover, the stored still image is displayed on a monitor (not shown). Thus, a still image of the subject H is displayed on the monitor. And, in order to immediately confirm the photographed still image after photography, the still image can be displayed on the operation panel 30.

[0098] (Structure of the irradiation unit)

[0099] The irradiation unit 18 includes a radiation source 31 and an irradiation field limiter 34. The radiation source 31 includes an X-ray tube 32 that generates radiation. The radiation is, for example, X-rays. The X-ray tube 32 generates radiation by causing electrons generated from the cathode to collide with a target (anode). The position where the electrons collide in the target becomes the focus of the emitted radiation.

[0100] And, an irradiation field limiter 34 is provided below the radiation source 31. The irradiation field limiter 34 (also called a collimator, etc.) has a rectangular irradiation opening 34A. The radiation generated in the X-ray tube 32 is irradiated onto the subject H through the irradiation opening 34A. The irradiation field limiter 34 can adjust the opening area of the irradiation opening 34A. The irradiation field limiter 34 has, for example, four shielding plates (not shown) that shield radiation. Each side of the four shielding plates corresponds to each side of the irradiation opening 34A and delimits the irradiation opening 34A. By changing the position of the shielding plates, the opening area of the irradiation opening 34A is adjusted, thereby changing the irradiation field of the radiation irradiated from the irradiation unit 18.

[0101] And, the irradiation unit 18 is configured to be rotatable relative to the arm 12 about the axis of a rotation shaft 36 that extends in the width direction of the radiation imaging device 10 (in Figure 1 this case, the Y direction). Specifically, a pair of mounting plates 38 ( Figure 1 only one is shown in this case) are fixed to one end of the arm 12.

[0102] The pair of mounting plates 38 are arranged so as to sandwich both sides in the width direction of the irradiation unit 18 and are connected to the surface on both sides in the width direction of the irradiation unit 18. Rotation shafts 36 are respectively protrudingly provided on each side surface of the irradiation unit 18 facing each mounting plate 38, and the rotation shafts 36 are respectively supported on the pair of mounting plates 38 via bearings (not shown). Thus, the irradiation unit 18 can rotate relative to the mounting plates 38 about the axis of the rotation shaft 36, and thereby the orientation of the irradiation opening 34A of the irradiation unit 18 can be changed in the front-rear direction of the arm 12. The irradiation direction of the radiation can be changed by changing the orientation of the irradiation opening 34A.

[0103] In addition, one ends of a plurality of cables 40 are connected to the irradiation unit 18. The plurality of cables 40 are wired with signal lines for transmitting control signals and power supply lines for power supply. As Figure 5 shown, the cable 40 is disposed on a hollow portion 42 formed within the arm 12 and extends along the arm 12. In addition, the other end of the cable 40 is connected to Figure 1 the control unit 28 of the main body unit 16 shown in and a power supply circuit (not shown) and the like.

[0104] (Structure of the image receiving unit)

[0105] As Figure 1 shown, the image receiving unit 20 is disposed at the other end of the arm 12, which is a position opposed to the irradiation unit 18. In the image receiving unit 20, a detector is non-removably built in a housing fixed to the arm 12. The image receiving unit 20 includes an image receiving surface 20A that receives radiation that has been irradiated from the irradiation unit 18 and has passed through the subject H. Radiation carrying information of the subject H is incident on the image receiving surface 20A.

[0106] The detector is, for example, a flat panel detector (FPD) of a digital radiography (DR) method. The FPD has a detection surface on which a plurality of pixels are two-dimensionally arranged and a thin film transistor (TFT) panel (not shown) for driving the pixels. Radiation is incident on the detection surface of the detector through the image receiving surface 20A. The detector converts the incident radiation into an electrical signal and outputs a radiation image of the subject H based on the converted electrical signal. As the detector, for example, an indirect conversion type is used. The indirect conversion type converts radiation into visible light through a scintillator and converts the converted visible light into an electrical signal. In addition, as the detector, a direct conversion type that converts radiation into a direct electrical signal may be used. Further, as the image receiving unit 20, a structure other than using an FPD may be employed. For example, a structure combining an image intensifier (I.I) and a camera may also be adopted.

[0107] In addition, the image receiving unit 20 is connected to the control unit 28 of the main body unit 16 and a power supply circuit (not shown) and the like through a cable (not shown) wired with signal lines for transmitting control signals and power supply lines for power supply.

[0108] (Structure of the friction mechanism)

[0109] As Figure 4 shown, a friction mechanism 44 is provided in the connection portion 14 of the radiation imaging apparatus 10. The friction mechanism 44 applies a frictional force in a direction opposite to the displacement direction of the arm 12 to the arm 12.

[0110] Specifically, both ends of the conveyor belt 46 constituting the first rotating mechanism 21 are respectively fixed to both ends of the arm 12. The arm 12 is composed of a tubular body having a cavity inside. As Figure 5 shown, the conveyor belt 46 and the cable 40 are provided in the hollow portion 42 inside the arm 12. In the hollow portion 42, a groove 42A extending along the arc of the arm 12 is formed on the inner side surface on the front side of the arm 12. The conveyor belt 46 extends along the arc of the arm 12 while being accommodated in the groove 42A. Thus, interference between the cable 40 and the conveyor belt 46 with each other in the hollow portion 42 of the arm 12 can be suppressed.

[0111] As Figure 6 and Figure 7 shown, a pulley shaft 48 constituting the first rotating mechanism 21 is provided in the connecting portion 14. As Figure 7 shown, the pulley shaft 48 is rotatably supported on the frame 52 of the connecting portion 14 via a bearing portion 50. And a pulley 54 can be coaxially and rotatably fixed to the pulley shaft 48, and the conveyor belt 46 is wound around the pulley 54.

[0112] As Figure 6 shown, the conveyor belt 46 is a timing conveyor belt formed with a plurality of teeth 46A. On the other hand, the pulley 54 is a timing pulley formed with a plurality of grooves 54A on the outer peripheral surface, and the conveyor belt 46 and the pulley 54 are linked by the engagement of the teeth 46A of the conveyor belt 46 and the grooves 54A of the pulley 54.

[0113] And, as Figure 4 shown, idle pulleys 56 are respectively provided above and below the pulley 54 in the connecting portion 14 in the vertical direction (Z direction). The conveyor belt 46 is guided while maintaining a predetermined tension by a pair of idle pulleys 56 and wound around the pulley 54.

[0114] When the arm 12 orbits and rotates relative to the rail portion 22B, the conveyor belt 46 follows the movement of the arm 12. For example, if one end of the arm 12 moves in a direction away from the connecting portion 14 (rail portion 22B), the conveyor belt 46 moves in the direction of the arrow P in Figure 6 , that is, one end moves in a direction away from the connecting portion 14. At this time, the pulley 54 engaged with the conveyor belt 46 also rotates in the direction of the arrow Q ( Figure 6 clockwise direction in

[0115] Further, a first gear 58 is fixedly mounted coaxially rotatable with a pulley 54 on a pulley shaft 48. A second gear 60 meshes with the first gear 58, and the second gear 60 is connected to a friction mechanism 44. The friction mechanism 44 includes a friction shaft 62, a frictional force generating portion 64 mounted on the friction shaft 62 for generating a frictional force, and a clutch 66 for switching between connection and disconnection of the pulley shaft 48 and the friction shaft 62.

[0116] As Figure 7 shown, the friction shaft 62 is rotatably supported on a frame 52 of the connecting portion 14 via a bearing portion 68. Further, the friction shaft 62 is inserted into a shaft hole 70A formed in a side plate 70. The side plate 70 is fixed to the frame 52 at a distance from the frame 52 in the axial direction ( Figure 7 Y direction in this case) of the friction shaft 62.

[0117] The frictional force generating portion 64 includes two sets of friction plates 72A, 72B that generate a frictional force by contact between frictional surfaces, and a biasing portion 74 that biases the frictional surfaces of the friction plates 72A, 72B toward each other. One set of the friction plates 72A, 72B is provided on each of the opposite end faces in the axial direction of the friction shaft 62 on the side plate 70.

[0118] Axial holes (not shown) are formed in the friction plates 72A, 72B respectively, and the friction plates 72A, 72B are mounted in a state movable in the axial direction of the friction shaft 62 by inserting the friction shaft 62 into these axial holes. In addition, one set of the friction plates 72A, 72B disposed between the side plate 70 and the frame 52 is restricted from moving in the axial direction of the friction shaft 62 by a restricting plate 76 fixed to the friction shaft 62.

[0119] Moreover, the friction plate 72A in contact with the end face of the side plate 70 is fixed by a rotation stopper (not shown) and thus becomes a fixed friction plate that does not rotate regardless of the rotation of the friction shaft 62. On the other hand, the friction plate 72B disposed on the outer side in the axial direction of the friction shaft 62 relative to the side plate 70 with respect to the friction plate 72A (fixed friction plate) becomes a rotating friction plate that rotates with the rotation of the friction shaft 62.

[0120] The biasing portion 74 is provided between one end in the axial direction of the friction shaft 62 and the side plate 70. The biasing portion 74 includes a disc spring unit 78, a pair of buffer plates 80, and a nut 82 provided at one end in the axial direction of the friction shaft 62.

[0121] The disc spring unit 78 is composed of a plurality of disc springs 78A. The disc spring 78A is a disc-shaped spring having a convex surface on one side and a concave surface on the other side. The plurality of disc springs 78A are stacked and arranged in the axial direction of the friction shaft 62.

[0122] Further, buffer plates 80 are respectively disposed axially outside in the friction shaft 62 of the disc spring unit 78. One buffer plate 80 is disposed between the disc spring unit 78 and the friction plate 72B. And, the other buffer plate 80 is disposed between the disc spring unit 78 and the nut 82. Additionally, shaft holes (not shown) are respectively formed in the buffer plate 80 and the disc spring 78A, and by inserting the friction shaft 62 through these shaft holes, the buffer plate 80 and the disc spring 78A are mounted in a state capable of moving in the axial direction of the friction shaft 62.

[0123] If the nut 82 is tightened in a state where the end face of the disc spring unit 78 abuts against one buffer plate 80, the disc spring unit 78 moves in the direction of pressing the one buffer plate 80. If the disc spring unit 78 moves, a pressing force is applied to each group of friction plates 72A, 72B via the buffer plate 80. If the nut 82 is further tightened and the disc spring unit 78 reaches the movement limit, the disc spring 78A elastically deforms and the disc spring unit 78 contracts in the axial direction of the friction shaft 62. The disc spring unit 78 applies a force in the direction of pressing the friction surfaces of the friction plates 72A, 72B against each other according to its elasticity.

[0124] Thus, by the action of the biasing portion 74, the friction surfaces of the friction plates 72A, 72B come into contact with each other, and a perpendicular resistance is generated on the friction surfaces. Therefore, if the friction shaft 62 attempts to rotate, a frictional force in the direction opposite to the rotation direction of the friction shaft 62 acts on the friction surfaces of the friction plates 72A, 72B.

[0125] A clutch 66 is mounted at the other end in the axial direction of the friction shaft 62. In the present embodiment, the clutch 66 is an electromagnetic clutch and includes a housing 84 having an electromagnet (not shown) built therein and a shaft fixing portion 86 fixed to the friction shaft 62. The housing 84 and the shaft fixing portion 86 are separated from each other. And, a biasing member (not shown) that biases the housing 84 and the shaft fixing portion 86 away from each other is provided between the housing 84 and the shaft fixing portion 86.

[0126] The housing 84 is fixed to the second gear 60. Shaft holes 60A, 84A through which the friction shaft 62 is inserted are respectively formed in the housing 84 and the second gear 60, and a gap is formed between the outer peripheral surface of the friction shaft 62 and the inner peripheral surfaces of the shaft holes 60A, 84A. That is, the housing 84 and the second gear 60 are not connected to the friction shaft 62.

[0127] The clutch 66 switches the connection and disconnection between the pulley shaft 48 and the friction shaft 62 by switching the connection and disconnection between the second gear 60 and the friction shaft 62. Specifically, when power is supplied to the clutch 66, a magnetic force is generated in the electromagnet built in the housing 84, and the shaft fixing portion 86 is attracted to the electromagnet side against the biasing force of the biasing member (not shown). Thereby, the housing 84 and the shaft fixing portion 86 are tightly connected.

[0128] In a state where the housing 84 is connected to the shaft fixing portion 86 (corresponding to the first state), when the pulley shaft 48 rotates, the housing 84 of the first gear 58, the second gear 60, and the clutch 66 rotates along with the rotation of the pulley shaft 48. Also, the shaft fixing portion 86 of the clutch 66 connected to the housing 84 and the friction shaft 62 to which the shaft fixing portion 86 is fixed rotate along with the rotation of the pulley shaft 48.

[0129] As described above, a frictional force in the direction opposite to the rotation direction acts on the friction shaft 62. Therefore, as the pulley shaft 48 rotates, the friction shaft 62 rotates, and thus a frictional force in the direction opposite to the rotation direction acts on the pulley shaft 48. A pulley 54 is fixed to the pulley shaft 48, and a conveyor belt 46 fixed to both ends of the arm 12 shown in Figure 4 is wound around the pulley 54.

[0130] Therefore, by a frictional force in the direction opposite to the rotation direction acting on the pulley shaft 48, when the arm 12 rotates along the track with respect to the track portion 22B (refer to Figure 4 ), a frictional force in the direction opposite to the rotation direction of the arm 12 acts on the arm 12.

[0131] On the other hand, when the clutch 66 is not energized, the housing 84 fixed to the second gear 60 and the shaft fixing portion 86 fixed to the friction shaft 62 are separated by the biasing force of a biasing member (not shown). Therefore, the housing 84 and the shaft fixing portion 86 are not connected, and the second gear 60 and the friction shaft 62 are not connected.

[0132] In a state where the housing 84 and the shaft fixing portion 86 are not connected (corresponding to the second state), when the pulley shaft 48 rotates, the housing 84 of the first gear 58, the second gear 60, and the clutch 66 rotates along with the rotation of the pulley shaft 48. However, the shaft fixing portion 86 of the clutch 66 and the friction shaft 62 do not rotate. Therefore, the frictional force acting on the friction shaft 62 when the pulley shaft 48 rotates does not act, and the frictional force acting on the arm 12 when the arm 12 rotates along the track is reduced compared to when the clutch 66 is energized.

[0133] The operator operates the operation panel 30 as an operation unit (refer to Figure 1 ) to switch between the first state and the second state of the above-described friction mechanism 44. For example, if the operator inputs an operation command to set the friction mechanism 44 to the first state to the operation panel 30, the control unit 28 (refer to Figure 1 ) sends a drive signal to the clutch 66, thereby energizing the clutch 66. As a result, the housing 84 of the clutch 66 and the shaft fixing portion 86 are connected, and the friction mechanism 44 becomes the first state in which a frictional force acts on the arm 12.

[0134] On the other hand, if the operator inputs an operation command to set the friction mechanism 44 to the second state to the operation panel 30, the control unit 28 (see Figure 1 ) cuts off the power supply to the clutch 66. As a result, the housing 84 and the shaft fixing portion 86 of the clutch 66 are not connected, and the friction mechanism 44 is in the second state in which the friction force does not act on the arm 12.

[0135] (Effect)

[0136] The radiation imaging device 10 according to this embodiment includes the first rotating mechanism 21 (an example of a displacement mechanism) for rotating the arm 12 relative to the connecting portion 14 , and the friction mechanism 44 for applying a friction force to the arm 12 in a direction opposite to the direction in which the arm 12 is rotated by the first rotating mechanism 21 .

[0137] Furthermore, the friction mechanism 44 can switch between a first state in which a friction force in a direction opposite to the displacement direction of the arm 12 acts on the arm 12 and a second state in which the friction force acting on the arm 12 is smaller than that in the first state. Therefore, the load based on the manual operation force of the arm 12 when the arm 12 is manually rotated can be changed by switching the friction mechanism 44 between the first state and the second state.

[0138] In particular, according to the present embodiment, the rotation operation of the arm 12 can be performed only by manual operation without relying on electric power. Therefore, the overall size and weight of the radiation imaging device 10 can be reduced. In addition, in the mechanism that displaces the arm by electric power, the radiation imaging device itself is usually a large device, and in the large device, the control of the operating force of the arm is usually achieved by a complex mechanism such as an electric mechanism.

[0139] Among them, according to this embodiment, the friction mechanism 44 can switch the operating force of the arm 12 with a relatively simple structure even when the rotation operation of the arm 12 is performed only by manual operation to make the radiation imaging device 10 small and light. Therefore, the technology of this embodiment is particularly effective for a small and light radiation imaging device 10 in which the rotation operation of the arm 12 is performed only by manual operation.

[0140] Furthermore, according to the present embodiment, the first rotating mechanism 21 has a pulley shaft 48 that rotates with the rotation of the arm 12. Furthermore, the friction mechanism 44 includes a friction shaft 62, a friction force generating portion 64 that is mounted on the friction shaft 62 and generates friction force, and a clutch 66 that switches between the first state and the second state by switching between connection and non-connection of the pulley shaft 48 and the friction shaft 62.

[0141] In this way, compared with the case where the first rotating mechanism 21 and the friction mechanism 44 are configured separately, each mechanism can be made compact by interlocking the components of the first rotating mechanism 21 and the components of the friction mechanism 44 .

[0142] In particular, according to the present embodiment, the first rotation mechanism 21 includes a pulley shaft 48 to which a pulley 54 is fixed, and a conveyor belt 46 whose both ends are fixed to both ends of the arm 12 and wound around the pulley 54. Thus, by winding the conveyor belt 46 fixed to both ends of the arm 12 around the pulley 54 fixed to the pulley shaft 48, even during the orbital rotation of the arm 12, the components of the first rotation mechanism 21 can be linked to the components of the friction mechanism 44.

[0143] Moreover, as a modification of the first rotation mechanism 21, a rack and pinion system or a system combining a chain and sprockets may be considered instead of the conveyor belt 46. However, by using the conveyor belt 46, weight reduction can be achieved compared to them.

[0144] In addition, as a displacement mechanism for displacing the arm 12, in addition to the first rotation mechanism 21 and the second rotation mechanism 23, for example, a sliding mechanism that slides the arm 12 in the horizontal direction (X direction) with respect to the main body portion 16 may be considered. However, generally, compared to the operation of sliding the arm 12 in the horizontal direction, the load of the rotation operation for rotating the arm 12 increases. Therefore, the friction mechanism 44 of the present embodiment capable of switching the frictional force is particularly effective when combined with the first rotation mechanism 21 or the second rotation mechanism 23.

[0145] That is, by setting the friction mechanism 44 to the first state, inadvertent rotation of the arm 12 can be prevented. On the other hand, by switching the friction mechanism 44 to the second state, the load during the manual rotation operation of the arm 12 can be reduced.

[0146] Furthermore, according to the present embodiment, the switching between the first state and the second state of the friction mechanism 44 is performed by the operator operating the operation panel 30 as an operation unit. That is, the operator can arbitrarily switch the frictional force.

[0147] Therefore, for example, when performing live imaging or the like using the radiation imaging device 10 during surgery, in the preparation stage before surgery, it is set so that positioning can be performed with a slight force by reducing the frictional force, and during surgery, by increasing the frictional force, it is possible to prevent accidental external forces such as the operator colliding with the arm 12 from being applied to the arm 12 and causing inadvertent rotation of the arm 12.

[0148] <Second Embodiment>

[0149] Next, with reference to FIGS. 8 to Figure 12 The radiation imaging device according to the second embodiment of the present invention will be described. In addition, the same reference numerals are given to the same structures as those in the first embodiment and the description thereof is omitted, and the description will be centered on the differences.

[0150] In the radiation imaging apparatus 10 of the first embodiment, the image receiving unit 20 is fixed to the other end of the arm 12. In contrast, as Figure 8A shown, in the radiation imaging apparatus 100 of the present embodiment, the image receiving unit 102 is configured to be removably mounted on the arm 12 in a movable manner. Further, similar to the first embodiment, the image receiving unit 102 has a detector non-removably built in the housing. Such a movable image receiving unit 102 is called an electronic cassette or the like.

[0151] (Structure of the image receiving unit)

[0152] Specifically, the image receiving unit 102 is removably mounted on a base 104 provided at the other end of the arm 12. The base 104 is provided on the upper surface of the other end of the arm 12, and a fitting convex portion 106 is erected above the base 104. The base 104 and the fitting convex portion 106 are each in the shape of a rectangular parallelepiped, and the width (length in the Y direction) of the fitting convex portion 106 is narrower than the width (length in the Y direction) of the base 104.

[0153] On the other hand, the image receiving unit 102 is in the shape of a flat rectangular parallelepiped, and a fitting concave portion 108 that fits with the fitting convex portion 106 is formed on the lower surface of the image receiving unit 102. The fitting concave portion 108 is in the shape of a rectangular parallelepiped, and the length in the short side direction ( Figure 8A the length in the Y direction in ) is wider than the width of the fitting convex portion 106 and narrower than the width of the base 104. Further, the height of the fitting concave portion 108 is substantially the same as the height of the fitting convex portion 106.

[0154] Moreover, the length in the long side direction of the fitting concave portion 108 ( Figure 8A the length in the X direction in ) is longer than the lengths (lengths in the X direction) of the base 104 and the fitting convex portion 106, and one end in the long side direction of the fitting concave portion 108 extends to one side surface of the image receiving unit 102. By having one end of the fitting concave portion 108 located on one side surface of the image receiving unit 102, a part of one side surface of the image receiving unit 102 is opened.

[0155] When the image receiving unit 102 is mounted on the arm 12, the image receiving unit 102 is moved in the horizontal direction (X direction), and the fitting convex portion 106 erected on the base 104 is inserted into the fitting concave portion 108 through the opening formed on one side surface of the image receiving unit 102. Thus, in a state where the fitting convex portion 106 is fitted into the fitting concave portion 108, the lower surface of the image receiving unit 102 abuts against the upper surface of the base 104.

[0156] Wherein, on the other end surface in the long side direction of the fitting recess 108, a pair of positioning pins 110 protruding inwardly of the fitting recess 108 are provided. On the other hand, when fitting with the fitting recess 108, a pair of pin holes 112 for inserting the positioning pins 110 are formed on one side surface of the fitting convex portion 106 facing the other end surface in the long side direction of the fitting recess 108.

[0157] When the fitting recess 108 of the image receiving portion 102 is fitted with the fitting convex portion 106, the pair of positioning pins 110 are respectively inserted into the pair of pin holes 112, so that the image receiving portion 102 is positioned and mounted on the base 104, that is, the other end of the arm 12.

[0158] And, a through hole 114 extending in the vertical direction (Z direction) is formed on the upper surface of the base 104, and a solenoid 116 is provided below the through hole 114 at the other end of the arm 12. Moreover, an insertion hole 118 having substantially the same diameter as the through hole 114 is also formed on the lower surface of the image receiving portion 102. Among them, as Figure 8B shown, when the image receiving portion 102 is positioned and mounted on the base 104, the insertion hole 118 of the image receiving portion 102 is formed at a position communicating with the through hole 114 of the base 104.

[0159] The solenoid 116 includes a movable iron core 116A inserted into the through hole 114, and is configured to be able to expand and contract the movable iron core 116A by switching the energized state and the non-energized state of the solenoid 116.

[0160] Specifically, when the solenoid 116 is energized, the movable iron core 116A is attracted to the main body side of the solenoid 116. As Figure 8B shown, the front end portion of the movable iron core 116A is located within the through hole 114 of the base. In this state, since the movable iron core 116A is not inserted into the insertion hole 118 of the image receiving portion 102, the image receiving portion 102 can be detached from and attached to the base 104, that is, the arm 12.

[0161] On the other hand, in the state where the insertion hole 118 of the image receiving portion 102 communicates with the through hole 114 of the base 104, that is, the state where the image receiving portion 102 is positioned and mounted on the other end of the arm 12, as Figure 8B shown, the movable iron core 116A can be inserted into the insertion hole 118 of the image receiving portion 102.

[0162] Therefore, in a state where the image receiving unit 102 is positioned and mounted at the other end of the arm 12, if the power supply to the solenoid 116 is cut off, the front end portion of the movable iron core 116A is inserted into the insertion hole 118 and reaches inside the image receiving unit 102. In this state, since the movable iron core 116A of the solenoid 116 is also inserted into the insertion hole 118 of the image receiving unit 102, detachment of the image receiving unit 102 from the base 104, i.e., the arm 12, is restricted. Thus, in a state where the image receiving unit 102 is mounted on the arm 12, the solenoid 116 constitutes a loading / unloading restricting mechanism that restricts inadvertent loading and unloading of the image receiving unit 102 with respect to the arm 12.

[0163] Moreover, a light sensor 120 is provided on the base 104, and the light sensor 120 serves as a loading / unloading detection unit that detects whether the image receiving unit 102 is detached from the arm 12. The light sensor 120 is, for example, a reflection type sensor in which a light emitting window for emitting light from a light emitting element (not shown) and a light receiving window for receiving light by a light receiving element (not shown) are arranged on the same surface. The light sensor 120 is provided at a position where, in a state where the image receiving unit 102 is not mounted on the base 104, the light emitting window and the light receiving window are exposed to the outside, and in a state where the image receiving unit 102 is mounted on the base 104, the light emitting window and the light receiving window are covered by the image receiving unit 102. For example, the light sensor 120 of this example is arranged on the base 104 in a posture facing the Figure 8A upper surface in.

[0164] For example, in the light sensor 120, in a state where the base 104 is mounted on the image receiving unit 102, the light emitted from the light emitting window is reflected by the image receiving unit 102, so that the amount of light received through the light receiving window increases. On the other hand, in a state where the image receiving unit 102 is detached from the base 104 and the image receiving unit 102 retreats from in front of the light emitting window and the light receiving window, the light is not reflected by the image receiving unit 102, so that the amount of light received through the light receiving window decreases.

[0165] Thus, the light sensor 120 can detect whether the image receiving unit 102 is detached from the arm 12 by detecting a change in the light emitted from the light emitting window and received by the light receiving element.

[0166] When the light sensor 120 detects that the image receiving unit 20 is mounted on the arm 12, it outputs an ON signal as a detection signal to the Figure 11 control unit 126 shown, and when it detects that the image receiving unit 20 is detached from the arm 12, it outputs an OFF signal as a detection signal to the Figure 11 control unit 126 shown.

[0167] In addition, the movable image receiving unit 102 has, for example, a battery (not shown) and a wireless communication unit, and is configured to be able to communicate with the control unit 126 provided on the main body unit 16 (refer toFigure 11 Wireless communications such as). When the wireless communication unit is used, the image receiving unit 102 is driven by power from the battery and can be used without a cable. Thus, the image receiving unit 102 is configured to be usable in a state detached from the arm 12.

[0168] On the other hand, in a state where the image receiving unit 102 is mounted on the arm 12, Figure 8A As shown, the terminal 122A provided on the fitting recess 108 of the image receiving unit 102 contacts the terminal 122B provided on the fitting projection 106 of the arm 12, so that the image receiving unit 102 is electrically connected to the base 104. The base 104 is connected to the control unit 126 (refer to Figure 11 ) of the main body unit 16 and an unillustrated power supply circuit etc. through a cable (not shown) wired with a signal line for transmitting a control signal and a power supply line for power supply. Thus, in a state where the image receiving unit 102 is mounted on the arm 12, the image receiving unit 102 is connected to the control unit 126 and an unillustrated power supply circuit etc. through an unillustrated cable.

[0169] (Structure of the connecting portion)

[0170] As Figure 9 and Figure 10 shown, similar to the first embodiment, in the connecting portion 14 of the radiation imaging apparatus 100, a conveyor belt 46, a pulley shaft 48, and a friction mechanism 44 constituting the first rotation mechanism 21 are provided. A pulley 54 is rotatably fixed coaxially on the pulley shaft 48, and the conveyor belt 46 is wound around the pulley 54.

[0171] The friction mechanism 44 has the same structure as that of the first embodiment and can switch between a first state in which a frictional force acts on the arm 12 and a second state in which the frictional force does not act on the arm 12. Among them, in this embodiment, when the friction mechanism 44 is in the first state, the frictional force acting on the arm 12 by the friction mechanism 44 is set to be at least a value larger than the maximum weight of the image receiving unit 102 that can be mounted on the arm 12.

[0172] Moreover, in this embodiment, in the connecting portion 14 of the radiation imaging apparatus 100, in addition to the friction mechanism 44, an electromagnetic brake 124 for locking the rotation of the arm 12 based on the first rotation mechanism 21 is provided. The electromagnetic brake 124 is connected to the pulley shaft 48 constituting the first rotation mechanism 21.

[0173] The electromagnetic brake 124 is, for example, a non-energized operation type. When not energized, the rotation is locked, and when energized, the rotation lock is released. By using a non-energized operation type electromagnetic brake 124 that locks rotation when not energized, the rotation of the arm 12 is locked when power supply to the electromagnetic brake 124 is cut off during a power outage or the like, so that inadvertent rotation of the arm 12 can be suppressed.

[0174] Specifically, the electromagnetic brake 124 includes a housing 124A in which an electromagnet (not shown) is built, and the pulley shaft 48 is mounted on the housing 124A via a rotor (not shown) provided in the housing 124A. The housing 124A is non-rotatably fixed to the connecting portion 14, and the rotor and the pulley shaft 48 are rotatable relative to the housing 124A.

[0175] Although not shown, the electromagnet and the rotor are arranged around the pulley shaft 48, and the electromagnet and the rotor are opposed to each other in the axial direction of the pulley shaft 48. Further, in the housing 124A, a movable iron piece that can move in the axial direction of the pulley shaft 48 is provided between the electromagnet and the rotor. The movable iron piece is separately arranged from the electromagnet, and is biased toward the rotor side by a biasing member (not shown) to press the rotor against the inner wall surface of the housing 124A.

[0176] When the electromagnetic brake 124 is not energized, the rotor is pressed against the inner wall surface of the housing 124A by the movable iron piece and is in close contact therewith, so that the rotation of the rotor relative to the housing 124A is locked. Further, since the rotation of the rotor relative to the housing 124A is locked, the rotation of the pulley shaft 48 fixed to the rotor and the pulley 54 fixed to the pulley shaft 48 is locked, and the movement of the conveyor belt 46 engaged with the pulley 54 is also locked.

[0177] As Figure 11 shown, both ends of the conveyor belt 46 are fixed to both ends of the arm 12. Therefore, since the movement of the conveyor belt 46 is locked, the orbital rotation of the arm 12 relative to the rail portion 22B is locked.

[0178] On the other hand, when the electromagnetic brake 124 is energized, a magnetic force is generated in the electromagnet built in the housing 124A, and the movable iron piece is attracted to the electromagnet side against the biasing force of the biasing member. As a result, the pressing of the rotor against the inner wall surface of the housing 124A by the movable iron piece is released, and the rotor can rotate relative to the housing 124A. That is, the rotation lock of the rotor is released.

[0179] And, since the rotation lock of the rotor is released, the rotation locks of the pulley shaft 48 and the pulley 54 are also released, and the conveyor belt 46 engaged with the pulley 54 can move. As a result, Figure 11 the lock of the orbital rotation of the arm 12 relative to the rail portion 22B shown is released.

[0180] (Structure of the control unit)

[0181] As shown Figure 11 in FIG. Figure 11 , the control unit 126 of the radiation imaging apparatus 100 controls the solenoid 116 provided at the other end of the arm 12.

[0182] Specifically, in a state where the attachment / detachment of the image reception unit 102 with respect to the arm 12 is restricted by the solenoid 116, when a release operation of the attachment / detachment restriction is performed via the operation panel 30 (see Figure 1 ), the control unit 126 sends a drive signal to the solenoid 116 and energizes the solenoid 116. Thereby, Figure 8B the movable iron core 116A shown in FIG. Figure 8B is attracted by the solenoid 116, so that the image reception unit 102 can be detached from the arm 12.

[0183] On the other hand, when a command for attachment / detachment restriction is input via the operation panel 30 (see Figure 1 ), the control unit 126 cuts off the power supply to the solenoid 116. In this case, in a state where the image reception unit 102 is mounted on the arm 12, as shown Figure 8B in FIG. Figure 8B , the insertion hole 118 of the image reception unit 102 communicates with the through hole 114 of the base 104. Therefore, the attachment / detachment of the image reception unit 102 with respect to the arm 12 is restricted by inserting the movable iron core 116A into the insertion hole 118 of the image reception unit 102.

[0184] In addition, even when a command for attachment / detachment restriction is input, when the image reception unit 102 is not mounted on the arm 12, that is, when the insertion hole 118 of the image reception unit 102 does not communicate with the through hole 114 of the base 104, the movable iron core 116A cannot be inserted into the insertion hole 118. Therefore, the attachment / detachment of the image reception unit 102 with respect to the arm 12 is not restricted.

[0185] In this way, the control unit 126 switches between a state allowing the attachment / detachment of the image reception unit 102 with respect to the arm 12 and a state restricting the attachment / detachment of the image reception unit 102 with respect to the arm 12 by controlling the power supply to the solenoid 116.

[0186] And, as shown Figure 11 in FIG. Figure 11 , the control unit 126 determines whether the image reception unit 102 is detached from the arm 12 based on a detection signal from the optical sensor 120 provided on the arm 12.

[0187] That is, as shown Figure 8B in FIG. Figure 8B , when the image reception unit 20 is mounted on the arm 12, the control unit 126 receives an ON signal as a detection signal from the optical sensor 120. When the control unit 126 receives the ON signal from the optical sensor 120, it determines that the image reception unit 102 is mounted on the arm 12.

[0188] On the other hand, as shownFigure 8A As shown, when the image receiving unit 102 is detached from the arm 12, the control unit 126 receives a close signal as a detection signal from the optical sensor 120. When the control unit 126 receives the close signal from the optical sensor 120, it determines that the image receiving unit 102 is detached from the arm 12.

[0189] Furthermore, the control unit 126 controls the friction mechanism 44 provided in the connection unit 14 according to an operation command from the operation panel 30. That is, if a switching command for the frictional force is input through the operation panel 30, the control unit 126, as in the first embodiment, sends a drive signal to the Figure 9 shown clutch 66 of the friction mechanism 44 to energize the clutch 66, thereby setting the friction mechanism 44 to the first state. On the other hand, the control unit 126 sets the friction mechanism 44 to the second state by cutting off the power supply to the clutch 66.

[0190] Moreover, the control unit 126 controls the electromagnetic brake 124 provided in the connection unit 14. That is, the control unit 126 locks Figure 9 shown rotation of the electromagnetic brake 124 relative to the pulley shaft 48 and the pulley 54 of the housing 124A, thereby locking the orbital rotation of the arm 12 relative to the rail portion 22B.

[0191] On the other hand, the control unit 126 energizes the electromagnetic brake 124 by sending a drive signal to the electromagnetic brake 124. As a result, the rotation lock of the pulley shaft 48 relative to the Figure 9 shown housing 124A is released. As a result, the lock of the orbital rotation of the arm 12 relative to the rail portion 22B is released by releasing the rotation lock of the pulley 54.

[0192] (Control Method of Radiographic Imaging Apparatus)

[0193] Next, a control method of the radiographic imaging apparatus 100 according to the present embodiment will be described with reference to the Figure 12 flowchart.

[0194] First, in step S500, when the power is turned on by operating a power switch (not shown) (Yes in step S500), the control unit 126 starts controlling the radiographic imaging apparatus 100. If the control based on the control unit 126 is started, input of imaging conditions and the like can be received through the operation panel 30.

[0195] In step S502, the control unit 126 determines whether the image receiving unit 102 is detached from the arm 12. Moreover, when it is determined that the image receiving unit 102 is detached from the arm 12 (Yes in step S502), the control unit 126 sets the friction mechanism 44 to the first state (step S504). That is, toFigure 9 The clutch 66 of the friction mechanism 44 shown is energized to connect the housing 84 and the shaft fixing portion 86.

[0196] In step S502, when it is determined that the image receiving unit 102 is mounted on the arm 12 (No in step S502), the control unit 126 sets the friction mechanism 44 to the second state (step S506). That is, the energization of the clutch 66 of the friction mechanism 44 shown is cut off to disconnect the housing 84 and the shaft fixing portion 86. Figure 9 The clutch 66 of the friction mechanism 44 shown is energized to disconnect the housing 84 and the shaft fixing portion 86.

[0197] In step S508, the control unit 126 determines whether the power of the radiation imaging apparatus 100 is cut off by an operator operating a power switch (not shown). Further, when the power of the radiation imaging apparatus 100 is not cut off (No in step S508), the process returns to step 502. On the other hand, when the power of the radiation imaging apparatus 100 is cut off (Yes in step S508), the control unit 126 ends the control of the radiation imaging apparatus 100.

[0198] (Function and effect)

[0199] In the radiation imaging apparatus 100 according to the present embodiment, similar to the radiation imaging apparatus 10 of the first embodiment, the first rotation mechanism 21 that rotates the arm 12 relative to the connection portion 14 is connected to the friction mechanism 44. Therefore, the load based on the manual operation force of the arm 12 can be changed by switching between the first state and the second state of the friction mechanism 44.

[0200] Further, in the radiation imaging apparatus 100 of the present embodiment, the image receiving unit 102 can be detachably mounted on the arm 12. Generally, when the arm 12 rotates, if the image receiving unit 102 is detachable, the weight balance changes greatly when the image receiving unit 102 is removed, and thus inadvertent rotation is likely to occur. Therefore, the friction mechanism 44 of the present embodiment is particularly effective for the radiation imaging apparatus 100 in which the image receiving unit 102 is detachable from the arm 12.

[0201] Moreover, the radiation imaging apparatus 100 of the present embodiment includes a light sensor 120 as an example of a loading and unloading detection unit that detects whether the image receiving unit 102 is removed from the arm 12. Further, the radiation imaging apparatus 100 includes a control unit 126 that performs control such that, in the light sensor 120, when it is detected that the image receiving unit 102 is removed from the arm 12, the friction mechanism 44 is set to the first state, and when it is detected that the image receiving unit 102 is mounted on the arm 12, the friction mechanism 44 is set to the second state.

[0202] Thus, by linking with the detachment of the image receiving unit 102, the friction mechanism 44 is set to the first state, that is, the frictional force acting on the arm 12 is increased, so that even when the image receiving unit 102 is detached, the inadvertent rotation of the arm 12 can be suppressed.

[0203] Moreover, according to the present embodiment, the frictional force that the friction mechanism 44 acts on the arm 12 is set to a value that is at least greater than the maximum weight of the image receiving unit 102 that can be mounted on the arm 12. Thus, by making the frictional force in the first state of the friction mechanism 44 greater than the weight of the image receiving unit 102, the change in the weight balance of the arm 12 during the detachment of the image receiving unit 102 can be absorbed by the frictional force, and thus the inadvertent rotation of the arm 12 can be more effectively suppressed.

[0204] Moreover, according to the present embodiment, an electromagnetic brake 124 that locks the rotation of the arm 12 based on the first rotation mechanism 21 is further provided, and the electromagnetic brake 124 is connected to the pulley shaft 48.

[0205] Thus, by providing the electromagnetic brake 124 in addition to the friction mechanism 44, the rotation of the arm 12 is locked by the electromagnetic brake 124, and thus the rotation of the arm 12 can be prohibited as needed. Moreover, compared with the case where the first rotation mechanism 21 and the electromagnetic brake 124 are configured independently, the respective mechanisms can be made more compact by connecting the components of the first rotation mechanism 21 and the electromagnetic brake 124.

[0206] <Third Embodiment>

[0207] Next, Figures 13-16 a radiation imaging apparatus according to the third embodiment of the present invention will be described. In addition, the same reference numerals are given to the same structures as those in the second embodiment and the description thereof is omitted, and the description will be centered on the differences.

[0208] In the radiation imaging apparatus 100 of the second embodiment, the pulley shaft 48 constituting the first rotation mechanism 21 is connected to the friction mechanism 44 and the electromagnetic brake 124. In contrast, as Figure 13 shown, in the radiation imaging apparatus 200 of the present embodiment, the support shaft 24 constituting the second rotation mechanism 23 is connected to the friction mechanism 202 and the electromagnetic brake 204.

[0209] (Structure of the main body unit)

[0210] As Figure 14 and Figure 15 shown, the friction mechanism 202 and the electromagnetic brake 204 are respectively provided on the main body unit 16 of the radiation imaging apparatus 200. In the main body unit 16, a third gear 206 is coaxially rotatably fixed on the outer peripheral surface of the support shaft 24, and a fourth gear 208 meshes with the third gear 206.

[0211] The friction mechanism 202 includes a friction shaft 210, a frictional force generating portion 212 that is mounted on the friction shaft 210 and generates a frictional force, and a clutch 214 that switches between connecting and disconnecting the support shaft 24 and the friction shaft 210.

[0212] The friction shaft 210 is supported on a frame 216 of the main body portion 16 via a bearing portion (not shown). And, a frictional force generating portion 212 is mounted on one axial end of the friction shaft 210. In the present embodiment, the frictional force generating portion 212 is constituted by, for example, a rotor damper.

[0213] Specifically, the frictional force generating portion 212 includes a rotor (not shown) fixed to one axial end of the friction shaft 210, a housing 212A that houses the rotor, and a viscous body (not shown) including oil or the like filled between the rotor and the housing 212A.

[0214] When the friction shaft 210 rotates, the rotor fixed to the friction shaft 210 rotates within the housing 212A. At this time, due to the viscous resistance of the viscous body filled in the housing 212A, a frictional force in the direction opposite to the rotation direction acts on the outer peripheral surface of the rotor. That is, a frictional force in the direction opposite to the rotation direction acts on the friction shaft 210.

[0215] And, a clutch 214 is mounted on the other axial end of the friction shaft 210. The clutch 214 is, for example, an electromagnetic clutch and has the same structure as the clutch 66 of the first embodiment and the second embodiment. That is, the clutch 214 includes a housing 218 fixed to the fourth gear 208 and a shaft fixing portion 220 fixed to the friction shaft 210.

[0216] When power is supplied to the clutch 214, the housing 218 and the shaft fixing portion 220 are connected (corresponding to the first state), and the frictional force in the direction opposite to the rotation direction acting on the friction shaft 210 acts on the support shaft 24 via the fourth gear 208 and the third gear 206. Thereby, when Figure 13 the arm 12 shaft shown rotates, a frictional force in the direction opposite to the rotation direction of the arm 12 acts on the arm 12.

[0217] On the other hand, when power supply to the clutch 214 is cut off, the housing 218 and the shaft fixing portion 220 become disconnected (corresponding to the second state), and the frictional force acting on the friction shaft 210 does not act on the support shaft 24. Thereby, compared with when power is supplied to the clutch 214, when Figure 13 the arm 12 shaft shown rotates, the frictional force acting on the arm 12 is reduced.

[0218] The electromagnetic brake 204 is installed at the other end of the support shaft 24. The electromagnetic brake 204 has the same structure as the electromagnetic brake 124 of the second embodiment. That is, the electromagnetic brake 204 includes a housing 204A that is non-rotatably fixed to the main body 16, and the support shaft 24 is rotatably installed on the housing 204A via a rotor provided in the housing 204A.

[0219] When the electromagnetic brake 204 is not energized, the rotor is pressed against the inner wall surface of the housing 204A by a movable iron piece (not shown) and is in close contact therewith. Therefore, the rotation of the rotor relative to the housing 204A is locked. Moreover, by locking the rotation of the rotor relative to the housing 204A, the rotation of the support shaft 24 fixed to the rotor is locked. By locking the rotation of the support shaft 24, Figure 13 the rotation of the arm 12 shown with respect to the axis of the bearing portion 25 is locked.

[0220] On the other hand, when the electromagnetic brake 204 is energized, a magnetic force is generated in an electromagnet (not shown) built in the housing 204A, and a movable iron piece (not shown) is attracted to the electromagnet side. As a result, the pressing of the rotor against the inner wall surface of the housing 204A by the movable iron piece is released, and the rotor can rotate relative to the housing 204A. That is, the rotation lock of the rotor is released.

[0221] And, by releasing the rotation lock of the rotor, the rotation lock of the support shaft 24 is also released. Thus, Figure 13 the lock of the rotation of the arm 12 shown with respect to the axis of the bearing portion 25 is released.

[0222] (Structure of the control unit)

[0223] As Figure 16 shown, similar to the second embodiment, the control unit 222 switches the state that permits the attachment and detachment of the image receiving unit 102 with respect to the arm 12 and the state that restricts the attachment and detachment of the image receiving unit 102 with respect to the arm 12 by controlling the energization of the solenoid 116.

[0224] And, similar to the second embodiment, the control unit 222 determines whether the image receiving unit 102 is detached from the arm 12 based on the detection signal from the optical sensor 120 provided in the image receiving unit 102.

[0225] And, the control unit 222 controls the friction mechanism 202 provided on the main body 16. That is, similar to the second embodiment, the control unit 222 energizes the clutch 214 of the friction mechanism 202 by sending a drive signal to the clutch 214, thereby setting the friction mechanism 202 to the first state. On the other hand, the control unit 222 sets the friction mechanism 202 to the second state by cutting off the energization of the clutch 214.

[0226] Furthermore, the control unit 222 controls the electromagnetic brake 204 provided on the main body 16. That is, similarly to the second embodiment, the control unit 222 energizes the electromagnetic brake by sending a drive signal to the electromagnetic brake 204. Figure 14 The rotation of the housing 204A of the electromagnetic brake 204 shown locks the axial rotation of the arm 12 relative to the bearing portion 25 .

[0227] On the other hand, the control unit 222 releases the support shaft 24 from the electromagnetic brake 204 by cutting off the power supply to the electromagnetic brake 204. Figure 14 The rotation lock of the housing 204A shown is thereby released, and the lock of the arm 12 on the axis of the bearing 25 is released.

[0228] The control flow of the control unit 222 of this embodiment is executed in the same steps as the control flow of the control unit 126 of the second embodiment. Figure 12 As shown, in step S502, the control unit 222 determines whether the image receiving unit 102 is removed from the arm 12, and when it is determined that the image receiving unit 102 is removed from the arm 12 ("Yes" in step S502), the control unit 222 sets the friction mechanism 202 to the first state. In step S502, when it is determined that the image receiving unit 102 is attached to the arm 12 ("No" in step S502), the control unit 222 sets the friction mechanism 202 to the second state.

[0229] (Effect)

[0230] According to the radiation imaging device 200 of the present embodiment, the second rotation mechanism 23 for rotating the arm 12 relative to the axis of the main body 16 and the friction mechanism 202 for applying a friction force in a direction opposite to the direction in which the arm 12 is rotated by the second rotation mechanism 23 to the arm 12. Therefore, similarly to the radiation imaging device 100 of the second embodiment, the load based on the manual operation force of the arm 12 can be changed by switching the first state and the second state of the friction mechanism 202.

[0231] Furthermore, according to the present embodiment, the friction mechanism 202 is connected to the support shaft 24 constituting the second rotating mechanism 23. Thus, even during the axial rotation of the arm 12, compared with the case where the second rotating mechanism 23 and the friction mechanism 202 are independently constituted, the components of the second rotating mechanism 23 and the components of the friction mechanism 202 can be linked to make each mechanism compact.

[0232] Furthermore, according to the present embodiment, the electromagnetic brake 204 for locking the rotation of the arm 12 by the second rotating mechanism 23 is further provided, and the electromagnetic brake 204 is connected to the support shaft 24 .

[0233] Thus, by providing the electromagnetic brake 204 in addition to the friction mechanism 202, the rotation of the arm 12 is pre-locked by the electromagnetic brake 204, and the rotation of the arm 12 can be prohibited as needed. Moreover, compared with the case where the second rotation mechanism 23 and the electromagnetic brake 204 are configured independently, the mechanisms can be made more compact by connecting the components of the second rotation mechanism 23 and the electromagnetic brake 204.

[0234] <Other Embodiments>

[0235] As described above, an example of an embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment and can be implemented in various ways without departing from the gist of the present invention. Moreover, the structures of the above-described embodiments can be appropriately combined.

[0236] For example, in the first embodiment, the first rotation mechanism 21 that rotates the arm 12 in an orbital manner is connected to the friction mechanism 44. However, the structure may be such that the second rotation mechanism 23 that rotates the arm 12 in an axial manner is connected to the friction mechanism 44. Moreover, the structure may be such that both the first rotation mechanism 21 and the second rotation mechanism 23 are respectively connected to the friction mechanism 44.

[0237] Moreover, in the first to third embodiments, the first rotation mechanism 21 or the second rotation mechanism 23 is connected to the friction mechanisms 44 and 202, and the frictional forces of the friction mechanisms 44 and 202 act on the arm 12 via the first rotation mechanism 21 or the second rotation mechanism 23. However, the structure may be such that the friction mechanisms 44 and 202 are mounted on the arm 12 itself, and the frictional forces of the friction mechanisms 44 and 202 directly act on the arm 12.

[0238] Similarly, in the second and third embodiments, the first rotation mechanism 21 or the second rotation mechanism 23 is connected to the electromagnetic brakes 124 and 204, and the rotation of the arm 12 is locked by locking the first rotation mechanism 21 or the second rotation mechanism 23. However, the structure may be such that the electromagnetic brakes 124 and 204 are mounted on the arm 12 itself, and the rotation of the arm 12 is directly locked by the electromagnetic brakes 124 and 204.

[0239] Moreover, as shown as a modification example in Figure 17 and Figure 18 , the structure may be such that a pair of operation handles 224 are provided on the connection portion 14 of the radiation imaging apparatus 100 of the second embodiment in addition to the friction mechanism 44 and the electromagnetic brake 124. The pair of operation handles 224 are provided separately from the arm 12 shown in Figure 11 , and an operating force for displacing the arm 12 relative to the first rotation mechanism 21 can be input by manual operation.

[0240] Specifically, a pair of operating handles 224 have the same structure and include a gripping portion 226 and a handle shaft 228 rotatably fixed coaxially to the gripping portion 226. The gripping portion 226 is the part where the operator holds the operating handle 224 with the hand. In this modified example, it has a cylindrical shape with an outer diameter larger than that of the handle shaft 228.

[0241] As Figure 18 shown, the handle shaft 228 is arranged in parallel with the pulley shaft 48 constituting the first rotation mechanism 21, and is rotatably supported on the side wall 229 of the connecting portion 14 via a bearing portion (not shown) and is axially movable. In addition, the handle shafts 228 of the pair of operating handles 224 are arranged on the same axis.

[0242] Moreover, one end of the handle shaft 228 of the operating handle 224 protrudes from the side wall 229 of the connecting portion 14 to the outside of the connecting portion 14, and the gripping portion 226 is provided at this one end of the handle shaft 228. That is, the gripping portions 226 of the pair of operating handles 224 are respectively provided protruding on both side surfaces of the connecting portion 14. Therefore, the operator can hold the gripping portions 226 from both sides of the connecting portion 14 to operate the operating handle 224.

[0243] A switching mechanism 230 is provided at the other end of the handle shaft 228 located within the connecting portion 14, and the switching mechanism 230 switches between an effective state in which the input of the operating force from the operating handle 224 to the first rotation mechanism 21 is effective and an ineffective state in which the input of the operating force is ineffective.

[0244] The switching mechanism 230 includes a pair of gears 232 respectively rotatably fixed coaxially to the other axial ends of the pair of handle shafts 228 and a biasing member 234 formed of a spiral spring or the like.

[0245] The pair of gears 232 are opposed to each other with a space therebetween in the axial direction of the handle shaft 228. And, in the axial direction of the handle shaft 228, a first gear 58 fixed to the pulley shaft 48 is provided between the pair of gears 232, and when the gears 232 move toward the other axial end side of the handle shaft 228, the first gear 58 meshes with the gears 232.

[0246] The biasing member 234 is provided between the pair of gears 232, and biases the gears 232 in the direction in which they separate from each other, that is, toward the one axial end side of the shaft portion. And, a spacer 236 is provided between the gear 232 and the side wall 229 of the connecting portion 14. The spacer 236 is a cylindrical member through which the handle shaft 228 is inserted, and the movement of the gear 232 toward the side wall 229, that is, the movement of the handle shaft 228 toward the one axial end side, is restricted by this spacer 236.

[0247] When operating the operation handle 224, the operator holds one of the pair of gripping portions 226 protruding from both side surfaces of the connecting portion 14 with a hand, and pushes the gripping portion 226 toward the inner side of the connecting portion 14, that is, the other end side in the axial direction of the handle shaft 228. At this time, the gear 232 of the switching mechanism 230 fixed to the axial end portion of the handle shaft 228 is biased toward one end side in the axial direction of the handle shaft 228 by the biasing member 234. Therefore, the operator presses the gripping portion 226 against the biasing force of the biasing member 234.

[0248] If the gripping portion 226 of one operation handle 224 is pressed, the handle shaft 228 moves toward the other end side in the axial direction, and the gear 232 fixed to the other end of the handle shaft 228 also moves toward the other end side in the axial direction. At this time, the gear 232 of the other operation handle 224 is restricted from moving toward one end side in the axial direction by the spacer 236, so it does not move in the axial direction, and one gear 232 approaches the other gear 232 against the biasing force of the biasing member 234. Thus, the first gear 58 disposed between the gears 232 meshes with one gear 232.

[0249] If the gripping portion 226 is rotated in a state where the first gear 58 meshes with one gear 232, the handle shaft 228 and the gear 232 rotate as the gripping portion 226 rotates, and the first gear 58 meshing with the gear 232 rotates. Moreover, the pulley shaft 48 and the pulley 54 fixed to the pulley shaft 48 rotate as the first gear 58 rotates. A conveyor belt 46 fixed to both ends of the arm 12 shown in Figure 11 is wound around the pulley 54, so the arm 12 rotates in an orbital manner as the pulley 54 rotates. That is, the arm 12 can be rotated by operating the operation handle 224.

[0250] In addition, in the case of the other operation handle 224, similarly to the case of one operation handle 224, the gripping portion 226 of the other operation handle 224 is pressed to mesh the other gear 232 with the first gear 58 to operate the other operation handle 224, so that the arm 12 can be rotated.

[0251] According to this modification example, the arm 12 can be operated by operating the operation handle 224 without directly operating the arm 12 itself. And since the arm 12 is displaced via the first rotation mechanism 21, it is easier to adjust the displacement amount of the arm 12 compared to the case of directly operating the arm 12 itself.

[0252] That is, regarding the relationship between the rotation amount of the operation handle 224 and the rotation amount of the arm 12, for example, it can be adjusted by setting the tooth number ratio of the first rotation mechanism 21. Therefore, it is relatively simple to set the rotation amount of the arm 12 to be smaller than the rotation amount of the operation handle 224. With such an operation handle 224, it is easy to finely adjust the rotation amount of the arm 12.

[0253] Moreover, the arm 12 of the irradiation unit 18 and the image receiving unit 102 is usually used during surgery. By separately providing the operation handle 224 from such an arm 12, the operation part operated by the surgeon and the operation part operated by the assistant can be separated. Therefore, methods such as rotating the arm 12 by the assistant to avoid the operation part contaminated by contact with the surgeon can also be used.

[0254] Moreover, in the above-described embodiment, the displacement mechanism for displacing the arm 12 is a rotation mechanism (the first rotation mechanism 21 and the second rotation mechanism 23) for rotating the arm 12. However, the displacement mechanism for displacing the arm 12 is not limited to the rotation mechanism. For example, as Figure 19 shown, it may be a sliding mechanism 240 for sliding the arm.

[0255] Specifically, the sliding mechanism 240 includes a rack 242 having one end fixed to the arm 12 and a pinion 244 provided on the main body 16. The rack 242 is formed with a plurality of teeth 242A on the lower surface and is movably mounted on the main body 16 in the horizontal direction (X direction). On the other hand, the pinion 244 is a circular gear formed with a plurality of teeth 244A on the outer peripheral surface and is fixed to the main body 16 so as to be rotatable about an axis.

[0256] By meshing the teeth 244A of the pinion 244 with the teeth 242A of the rack 242, the rack 242 and the pinion 244 are interlocked. Therefore, if the arm 12 is manually slid relative to the main body 16, the rack 242 slides in the direction of arrow R, and the pinion 244 meshing with the rack 242 rotates.

[0257] Moreover, a gear (not shown) meshes with the pinion 244, and this gear is connected to the friction mechanism 44. The friction mechanism 44 has the same structure as that of the first embodiment and can switch the connected and unconnected states with the gear through the clutch 66 (refer to Figure 6 ).

[0258] If the clutch 66 is energized to connect the gear and the friction mechanism 44 (corresponding to the first state), the frictional force of the friction mechanism 44 acts on the pinion 244. In this case, if the rack 242 is slid to rotate the pinion 244, a frictional force in the direction opposite to the moving direction of the rack 242 acts on the rack 242. Thereby, the frictional force can act on the arm 12.

[0259] On the other hand, if the power supply to the clutch 66 is cut off to disconnect the gear from the friction mechanism 44 (corresponding to the second state), the frictional force of the friction mechanism 44 does not act on the pinion 244. In this case, even if the rack 242 is slid to rotate the pinion 244, the frictional force of the friction mechanism 44 does not act on the rack 242 and the arm 12. Thus, it is also possible to cause the frictional force of the friction mechanism 44 to act on the sliding of the arm 12.

[0260] Moreover, in the second embodiment, the image receiving unit 102 that can be detachably mounted on the arm 12 is constituted by a detector that is non-detachably built into the housing. However, as shown as a modification example in Figure 20A and Figure 20B , the image receiving unit 246 that can be detachably mounted on the arm 12 may also be constituted by the detector 248 and the housing portion 250.

[0261] Specifically, the detector 248 can be detachably housed in the housing portion 250, and the housing portion 250 can be detachably mounted on the arm 12. The meaning that the detector 248 is detachable from the housing portion 250 is the same as the meaning that the detector 248 is detachable from the arm 12. Therefore, with this structure, the size of the detector 248 mounted on the arm 12 can be changed.

[0262] Moreover, the housing portion 250 is also detachable from the arm 12. Thus, when the size of the detector 248 is changed, it is easy to maintain the weight balance of the arm 12. The C-arm shown as an example of the arm 12 prevents accidental orbital rotation by achieving the weight balance between the irradiation unit 18 (refer to Figure 11 ) held at both ends and the image receiving unit 246, and thus can stop at an arbitrary rotational position.

[0263] More specifically, the rotation center of the orbital rotation of the arm 12 (which coincides with the axis M in Figure 2A ) coincides with the center of gravity of the entire arm 12 including the irradiation unit 18 and the image receiving unit 246. Thus, the arm 12 can stop at an arbitrary rotational position by the action of the weight balance of the arm 12.

[0264] If the size of the detector 248 is changed, the weight of the image receiving unit 246 changes, and thus the center of gravity of the arm 12 also deviates from the rotation center of the orbital rotation. Therefore, by making the housing portion 250 other than the detector 248 also detachable from the arm 12, the weight change of the detector 248 can be compensated by changing the housing portion 250. As the housing portion 250, for example, a variety of housing portions with different weights can be prepared by changing the ballast for weight adjustment, etc. By separately using these various housing portions 250, the weight change amount caused by the size change of the detector 248 can be compensated.

[0265] Accordingly, even when the size of the detector 248 is changed, by correspondingly changing the housing part 250, it is possible to maintain the weight balance between the irradiation part 18 and the image receiving part 246 and make the center of gravity of the arm 12 coincide with the center of the orbital rotation.

[0266] Similar to the detectors of the first and second embodiments, the detector 248 constituting the image receiving part 246 is formed of, for example, a flat panel detector or the like, and detects the radiation image of the subject H by receiving the radiation that has irradiated the subject H and transmitted through the image receiving surface 248A from the Figure 1 irradiation part 18 shown. In the present embodiment, the detector 248 functions as a mobile electronic cassette.

[0267] The housing part 250 constituting the image receiving part 246 is a flat rectangular parallelepiped-shaped box, and has a fitting recess 252 formed on the lower surface and a housing recess 254 that houses the detector 248. The fitting recess 252 has the same structure as the fitting recess 108 formed on the lower surface of the image receiving part 102 of the second embodiment, and the housing part 250 can be detachably attached to the arm 12 by fitting the fitting convex part 106 provided at the other end of the arm 12 into the fitting recess 252.

[0268] And, similar to the second embodiment, a solenoid 116 that restricts the attachment and detachment of the housing part 250 with respect to the arm 12 and a light sensor 120 as an attachment and detachment detection part are provided on the arm 12. In the present embodiment, the light sensor 120 detects whether the housing part 250 is detached from the arm 12, that is, whether both the housing part 250 constituting the image receiving part 246 and the detector 248 are detached from the arm 12.

[0269] As Figure 20A shown, an opening 254A for housing the detector 248 in the housing recess 254 is formed on one of the four side surfaces of the housing part 250. And, a square-shaped opening 254B that communicates with the housing recess 254 is also formed on the upper surface of the housing part 250 that faces the irradiation opening 34A (refer to Figure 1 ) of the irradiation part 18.

[0270] In a state where the detector 248 is housed in the housing recess 254, as Figure 20B shown, the image receiving surface 248A of the detector 248 is exposed from the opening 254B formed on the upper surface of the housing part 250. Accordingly, even when the detector 248 is in a state of being mounted on the housing part 250, that is, on the arm 12, the radiation irradiated from the irradiation part 18 (refer to Figure 1 ) can be received by the image receiving surface 248A of the detector 248.

[0271] The storage portion 250 is provided with a light sensor 256 for detecting whether the detector 248 is removed from the storage portion 250. The light sensor 256 is provided on the side surface of the storage recess 254 opposite to the side surface where the opening 254A of the storage portion 250 is formed.

[0272] The optical sensor 256 has the same structure as the optical sensor 120, and by detecting the change in the amount of light emitted from the light emitting element and received by the light receiving element, it is possible to detect whether the detector 248 is in the receiving recess 254. In addition, the sensor for detecting whether the detector 248 is removed from the receiving portion 250 is not limited to the optical sensor 256, and may be, for example, a contact sensor or a micro switch using a piezoelectric element.

[0273] Furthermore, in addition to the optical sensor 256, a loading and unloading restriction mechanism (not shown) may be provided in the accommodation recess 254, which fixes the detector 248 in the accommodation recess 254 and prevents the detector 248 from falling off, and releases the prevention state.

[0274] Generally, the housing portion 250 is mounted on the arm 12 , and the change in weight balance of the arm 12 is smaller when the detector 248 is detached from the housing portion 250 than when both the housing portion 250 and the detector 248 are detached from the arm 12 .

[0275] In this modification, for example, when the optical sensor 120 detects that the housing portion 250 is mounted on the arm 12 and the optical sensor 256 detects that the detector 248 is removed from the housing portion 250, the friction mechanism 44 is set to the first state. That is, by increasing the friction force acting on the arm 12 in conjunction with the removal of the detector 248, it is possible to suppress the arm 12 from rotating unintentionally when the detector 248 is removed.

[0276] In addition, the friction force of the friction mechanism 44 may be changed in three stages: when the image receiving unit 246 (i.e., the detector 248 and the storage unit 250) is mounted on the arm 12, when only the storage unit 250 is mounted on the arm 12, and when the image receiving unit 246 is not mounted on the arm 12. In this case, the friction force acting on the arm 12 can be adjusted according to the magnitude of the change in the weight balance of the arm 12.

[0277] Furthermore, in the above-described embodiment, the displacement operation (rotation operation) of the arm 12 can be performed only by manual operation, but the arm 12 may be rotated by electric operation, or the manual operation and the electric operation may be switched.

[0278] Furthermore, in the above-described embodiment, the first rotating mechanism 21 is composed of the rail portion 22B and the pulley shaft 48 provided in the connecting portion 14, the fitting portion 22A formed on the arm 12, and the belt 46 fixed to both ends of the arm 12. However, the first rotating mechanism 21 may be any structure as long as it is a structure capable of orbital rotation of the arm 12 relative to the connecting portion 14 as a support portion.

[0279] For example, the first rotating mechanism may be constituted by a pinion coaxially rotatably fixed to a rotating shaft (not shown) provided in the connecting portion 14 and a rack (not shown) provided on the outer peripheral surface of the arm 12 and having a plurality of teeth meshing with the pinion.

[0280] Furthermore, in the above-mentioned embodiment, the "second state" of the friction mechanism 44 is a state in which the friction force of the friction shaft 62 does not act on the arm 12 (a state in which the friction force acting is 0). However, the "second state" of the friction mechanism 44 only needs to reduce the friction force acting on the arm 12 at least as much as that in the "first state", and the friction force is not limited to the state of 0. For example, by adjusting the friction force based on Figure 7 The friction force acting on the friction shaft 62 is reduced compared to the "first state" by the tightening force of the nut 82 shown, thereby setting the friction mechanism 44 to the "second state".

[0281] Furthermore, in the above-mentioned embodiment, the friction force when the friction mechanism 44 is in the "first state" is greater than the maximum weight of the image receiving unit 102 that can be mounted on the arm 12. However, the friction force when the friction mechanism 44 is in the "first state" may be smaller than the maximum weight of the image receiving unit 102 that can be mounted on the arm 12.

[0282] In this case, the arm 12 rotates when the image receiving unit 102 is removed from the arm 12, but as long as the difference between the friction force and the weight is small, the momentum of the rotation can be reduced, so that even in this case, the effect of reducing the momentum of the rotation of the arm 12 can be obtained.

[0283] Furthermore, in the above embodiment, an electromagnetic clutch is used as the clutch 66 constituting the friction mechanism 44 , but the clutch 66 is not limited to the electromagnetic clutch, and other well-known clutches such as a powder clutch may be used.

[0284] Furthermore, in the above-mentioned embodiments, an arm (C-arm) capable of orbital rotation and axial rotation is described as an example of the arm 12, but an arm capable of only axial rotation (for example, a U-arm whose side shape is a U-shape) may also be used. The U-arm can also hold the irradiation unit 18 and the image receiving unit 20, 102, etc. in an opposing posture, similar to the C-arm.

[0285] In addition, X-rays are taken as an example of the radiation, but it is not limited to X-rays and can also be γ-rays or the like.

[0286] In the above-described embodiments, as the hardware structure of the processing unit (Processing Unit) such as the control unit 28 that executes various processes, various processors (Processor) as shown below can be used. Among the various processors, as described above, in addition to the general-purpose processor, i.e., the CPU, which executes software to function as various processing units, there are also processors such as FPGAs (Field Programmable Gate Arrays), i.e., programmable logic devices (Programmable Logic Devices: PLDs), whose circuit structures can be changed after manufacturing, and ASICs (Application Specific Integrated Circuits), i.e., dedicated circuits, which are processors with circuit structures specifically designed to execute specific processes.

[0287] One processing unit can be constituted by one of these various processors, or can be constituted by a combination of two or more processors of the same type or different types (for example, a combination of multiple FPGAs and / or a combination of a CPU and an FPGA). Moreover, multiple processing units can be constituted by one processor.

[0288] As an example of constituting multiple processing units by one processor, firstly, there is a method in which one processor is constituted by a combination of one or more CPUs and software, and this processor functions as multiple processing units. Secondly, there is a method in which, represented by a system on chip (SoC) or the like, a processor that uses one IC (Integrated Circuit) chip to implement the functions of the entire system including multiple processing units is used. In this way, one or more of the above various processors are used as the hardware structure to constitute various processing units.

[0289] Furthermore, as the hardware structure of these various processors, more specifically, a circuit (circuitry) that combines circuit elements such as semiconductor elements can be used.

Claims

1. A radiation imaging device, comprising: An irradiation unit that irradiates radiation; An arm that can hold the irradiation unit and an image reception unit that receives the radiation irradiated by the irradiation unit and transmitted through a subject in an opposed posture; A support unit that supports the arm; A displacement mechanism that displaces the arm relative to the support unit; And A friction mechanism that can switch between a first state in which a frictional force in a direction opposite to the displacement direction of the arm acts on the arm and a second state in which the frictional force acting on the arm is reduced compared to the first state, The displacement mechanism is a rotation mechanism that rotates the arm, The image reception unit is detachable from the arm, The radiation imaging device further comprises: A detachment detection unit that detects whether the image reception unit is detached from the arm; and A control unit that performs control such that, in the detachment detection unit, when it is detected that the image reception unit is detached from the arm, the friction mechanism is set to the first state, and when it is detected that the image reception unit is mounted on the arm, the friction mechanism is set to the second state.

2. The radiation imaging device according to claim 1, Wherein, The frictional force in the first state is greater than the maximum weight of the image reception unit that can be mounted on the arm.

3. The radiation imaging device according to claim 1, Wherein, The radiation imaging device has an electromagnetic brake that locks the rotation of the arm based on the rotation mechanism.

4. The radiation imaging device according to claim 1, Wherein, The rotation mechanism has a rotation shaft that rotates as the arm rotates, The friction mechanism includes: a friction shaft; a frictional force generation unit that is mounted on the friction shaft and generates a frictional force; and a clutch that switches between the first state and the second state by switching between connection and non-connection of the rotation shaft and the friction shaft.

5. The radiation imaging device according to claim 3, Wherein, The rotation mechanism has a rotation shaft that rotates as the arm rotates, The electromagnetic brake is connected to the rotation shaft.

6. The radiation imaging device according to claim 4, Wherein, The arm is formed in an arc shape in a side view, The rotation mechanism includes a first rotation mechanism that includes: a track portion that is provided on the support unit and movably supports the arm along the arc shape; a fitting portion that is formed on the outer peripheral portion of the arm and fits with the track portion; and a first rotation shaft that serves as the rotation shaft, The arm can perform orbital rotation with the center of the arc shape as the rotation center by moving relative to the track portion.

7. The radiation imaging device according to claim 6, Wherein, The rotation mechanism further has a conveyor belt, one end of which is fixed to the end side of the arm where the irradiation unit is provided, and the other end of which is fixed to the end side of the arm where the image reception unit is provided, The conveyor belt is wound around the first rotation shaft.

8. The radiation imaging device according to claim 4, Wherein, The rotation mechanism includes a second rotation mechanism, and the second rotation mechanism includes: a second rotation shaft as the rotation axis, one end of which is fixed to the arm; and a bearing portion provided on the support portion. The arm can reverse the positions of the irradiation portion and the image receiving portion relative to the subject by rotating about the axis of the second rotation shaft with respect to the bearing portion.

9. The radiation imaging apparatus according to claim 3, wherein, the rotation mechanism has a rotation axis that rotates as the arm rotates, the friction mechanism includes: a friction shaft; a frictional force generating portion installed on the friction shaft and generating a frictional force; and a clutch that switches between the connected state and the disconnected state of the rotation axis and the friction shaft to switch between the first state and the second state.

10. The radiation imaging apparatus according to claim 9, wherein, the rotation mechanism has a rotation axis that rotates as the arm rotates, the electromagnetic brake is connected to the rotation axis.

11. The radiation imaging apparatus according to claim 5, wherein, the arm is formed in an arc shape in a side view, the rotation mechanism includes a first rotation mechanism, and the first rotation mechanism includes: a track portion provided on the support portion and movably supporting the arm along the arc shape; a fitting portion formed on the outer peripheral portion of the arm and fitted to the track portion; and a first rotation shaft as the rotation axis. The arm can perform an orbital rotation with the center of the arc shape as the rotation center by moving relative to the track portion.

12. The radiation imaging apparatus according to any one of claims 1 to 11, wherein, the radiation imaging apparatus includes an operation portion that switches between the first state and the second state of the friction mechanism.

13. The radiation imaging apparatus according to any one of claims 1 to 11, wherein, the displacement operation of the arm can be performed only by manual operation.

14. The radiation imaging apparatus according to any one of claims 1 to 11, wherein, the radiation imaging apparatus has an operation handle that is provided separately from the arm and can input an operation force for displacing the arm relative to the displacement mechanism by manual operation.

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