Patent Description:
A radiography apparatus (X-ray apparatus) has been known which includes an arm having two ends. An irradiation unit (X-ray tube) that emits radiation is provided at one end of the arm. An image receiving unit (image receiving device) that receives the radiation emitted from the irradiation unit is provided at the other end of the arm. This arm is supported so as to be rotatable with respect to a main body of the radiography apparatus. The arm is rotated such that the irradiation unit and the image receiving unit can be positioned in any posture around a subject while maintaining a relative position. In addition, in a radiography apparatus disclosed in <CIT> (<CIT>), an arm can be manually rotated. <CIT> and <CIT> each disclose a C-arm which comprises a a friction mechanism that is switchable between a first state in which a frictional force is applied to the arm in a direction opposite to a direction in which the arm is displaced and a second state in which the frictional force applied to the arm is less than the frictional force in the first state.

In a case in which the arm is manually operated, the load of an operation force may be small or large according to circumstances. For example, a case in which the radiography apparatus is used during surgery is considered. In this case, it is preferable that the load of the operation force of the arm is small in a positioning stage before surgery. After the surgery is started, it is preferable that the arm is not inadvertently rotated due to contact with a person.

In particular, in the case of an arm that holds both the irradiation unit and the image receiving unit, the weight of the arm is greater than that of an arm that holds only the irradiation unit. Therefore, there is a great need to reduce the load of the operation force due to a manual operation. In a case in which the load of the operation force is always small, inadvertent rotation is likely to occur, which is not preferable. <CIT> (<CIT>) does not disclose and suggest the problems and measures. Therefore, there has been a demand for measures to solve these problems.

An object of the technology according to the present disclosure is to provide a radiography apparatus that can change a load due to a manual operation force of an arm.

According to a first aspect of the present disclosure, there is provided a radiography apparatus according to claim <NUM>.

According to the above-mentioned configuration, the radiography apparatus comprises the displacement mechanism that displaces the arm and the friction mechanism that is switchable between the first state in which the frictional force is applied to the arm in the direction opposite to the direction in which the arm is displaced and the second state in which the frictional force applied to the arm is less than that in the first state. Therefore, the friction mechanism is switched between the first state and the second state to change a load due to the manual operation force of the arm.

According to a second aspect of the present disclosure, the radiography apparatus according to the first aspect may further comprise an operation portion that switches the friction mechanism between the first state and the second state.

According to the above-mentioned configuration, the operator can optionally switch the frictional force. For example, before surgery, it is possible to reduce the frictional force such that positioning is performed with a small force. During surgery, it is possible to increase the frictional force in order to prevent the arm from being inadvertently rotated due to the application of an unintended external force to the arm such as the collision of the operator with the arm.

According to a third aspect of the present disclosure, in the radiography apparatus according to the first aspect or the second aspect, the arm may be displaced by only a manual operation.

According to the above-mentioned configuration, the arm is not displaced by an electromotive force, but can be displaced by only a manual operation. Therefore, it is possible to reduce the size and weight of the entire radiography apparatus. In many cases, a large-sized radiography apparatus includes a mechanism that electrically displaces the arm. In general, in the large-sized apparatus, the operation force of the arm is controlled through a complicated mechanism such as an electric mechanism.

Here, the friction mechanism according to the technology of the present disclosure can switch the operation force of the arm with a relatively simple structure even in a case in which the arm is displaced by only a manual operation to reduce the size and weight of the apparatus. Therefore, the technology of the present disclosure is particularly effective for an apparatus with a small size and weight in which the arm is displaced by only a manual operation.

The displacement mechanism is a rotation mechanism that rotates the arm.

According to the above-mentioned configuration, a load is applied in the rotation operation of rotating the arm, as compared to an operation of sliding the arm in the horizontal direction. Therefore, this configuration is particularly effective in a case in which the friction mechanism capable of switching the frictional force is combined with the rotation mechanism.

According to a further aspect of the present disclosure, in the radiography apparatus according to the aforementioned aspect, the image receiving unit may be attachable to and detachable from the arm.

According to the above-mentioned configuration, in a case in which the arm is rotated and the image receiving unit is attachable and detachable, a weight balance changes greatly during the detachment of the image receiving unit. As a result, inadvertent rotation is likely to occur. Therefore, for example, in a case in which the image receiving unit is detached, the frictional force is increased to suppress inadvertent rotation.

According to a further aspect of the present disclosure, the radiography apparatus according to the aforementioned aspect may further comprise: an attachment and detachment detection unit that detects whether or not the image receiving unit is detached from the arm; and a control unit that performs control to switch the friction mechanism to the first state in a case in which the attachment and detachment detection unit detects that the image receiving unit is detached from the arm and to switch the friction mechanism to the second state in a case in which the attachment and detachment detection unit detects that the image receiving unit is attached to the arm.

In a case in which the image receiving unit is detached from the arm, the weight balance of the arm may change and the arm may be inadvertently rotated. Here, according to the above-mentioned configuration, the frictional force is increased in operative association with the detachment of the image receiving unit. Therefore, it is possible to suppress the inadvertent rotation of the arm even in a case in which the image receiving unit is detached.

According to a further aspect of the present disclosure, in the radiography apparatus according to the aforementioned aspect, the frictional force in the first state may be greater than a maximum weight of the image receiving unit that is capable of being attached to the arm.

According to the above-mentioned configuration, since the frictional force in the first state is greater than the weight of the image receiving unit, a change in the weight balance of the arm in a case in which the image receiving unit is detached can be absorbed by the frictional force and it is possible to further suppress the inadvertent rotation of the arm.

The radiography apparatus further comprises an electromagnetic brake that locks the rotation of the arm by the rotation mechanism.

The radiography apparatus includes the electromagnetic brake that locks the rotation of the arm in addition to the friction mechanism. Therefore, the electromagnetic brake locks the rotation of the arm to prohibit the rotation of the arm as necessary.

The rotation mechanism has a rotation shaft that is rotated with the rotation of the arm and the friction mechanism comprises a friction shaft, a frictional force generation unit that is attached to the friction shaft and generates a frictional force, and a clutch that switches connection and disconnection between the rotation shaft and the friction shaft to switch between the first state and the second state.

According to the above-mentioned configuration, the components of the rotation mechanism and the components of the friction mechanism are operatively associated with each other to reduce the size of each mechanism, as compared to a case in which the rotation mechanism and the friction mechanism are independently configured.

According to a further aspect of the present disclosure, the rotation mechanism may have a rotation shaft that is rotated with the rotation of the arm and the electromagnetic brake may be connected to the rotation shaft.

According to the above-mentioned configuration, the components of the rotation mechanism and the electromagnetic brake are connected to each other to reduce the size of each mechanism, as compared to a case in which the rotation mechanism and the electromagnetic brake are independently configured.

According to a further aspect of the present disclosure, the arm may have an arc shape in a side view. The rotation mechanism may include a first rotation mechanism comprising a track portion that is provided in the support portion and supports the arm so as to be movable along the arc shape, a fitting portion that is formed in an outer peripheral portion of the arm and is fitted to the track portion, and a first rotation shaft as the rotation shaft. The arm may be moved with respect to the track portion to be orbitally rotated about a center of the arc shape as a rotation center.

According to the above-mentioned configuration, since the arm can be orbitally rotated along the arc shape, the irradiation unit and the image receiving unit can be rotated about the body axis of the subject.

According to a further aspect of the present disclosure, the rotation mechanism may further include a belt that has one end fixed to an end of the arm at which the irradiation unit is provided and the other end fixed to an end f the arm at which the image receiving unit is provided. The belt may be wound around the first rotation shaft.

According to the above-mentioned configuration, it is possible to operatively associate the components of the rotation mechanism with the components of the friction mechanism even in orbital rotation and to reduce the size of each mechanism, as compared to a case in which the rotation mechanism and the friction mechanism are independently configured.

Further, as a modification example of the orbital rotation mechanism, a rack and pinion system or a system in which a chain and a sprocket are combined are considered instead of the belt. However, in a case in which the belt is used, the weight of the apparatus can be less than that in these systems.

According to a further aspect of the present disclosure, in the radiography apparatus according to any one of the last three aspects, the rotation mechanism may include a second rotation mechanism comprising a second rotation shaft as the rotation shaft that has one end fixed to the arm and a bearing that is provided in the support portion. The arm may be rotated about the second rotation shaft with respect to the bearing to reverse positions of the irradiation unit and the image receiving unit with respect to the subject.

According to the above-mentioned configuration, since the arm is rotatable about the rotation shaft, it is possible to switch between an overtube posture in which the irradiation unit is disposed above the image receiving unit and an undertube posture in which the irradiation unit is disposed below the image receiving unit.

According to a further aspect of the present disclosure, the radiography apparatus may further comprise an operation handle that is provided independently of the arm and is manually operated to input an operation force for displacing the arm to the displacement mechanism.

According to the above-mentioned configuration, the operation handle makes it possible to operate the arm, without directly operating the arm. Further, since the arm is displaced through the displacement mechanism, the amount of displacement of the arm can be adjusted more easily than that in a case in which the arm is directly operated.

That is, the gear ratio of the displacement mechanism can be set to adjust the relationship between the amount of operation of the operation handle and the amount of displacement of the arm. Therefore, the setting of reducing the amount of displacement of the arm with respect to the amount of displacement of the operation handle is relatively simple. The operation handle makes it easy to finely adjust the amount of displacement of the arm.

In many cases, the arm that holds the irradiation unit and the image receiving unit is used during surgery. Since the operation handle is provided independently of the arm, it is possible to separate an operation part operated by the operator from an operation part operated by the assistant. Therefore, the following method can also be used: the assistant rotates the arm while avoiding the operation part contaminated by contact with the operator.

According to the technology of the present disclosure, it is possible to change a load due to the manual operation force of the arm.

Hereinafter, radiography apparatuses according to first to third embodiments of the present disclosure will be sequentially described with reference to the drawings. In the drawings, an arrow X indicates the front-rear direction of the radiography apparatus, an arrow Y indicates the width direction of the radiography apparatus, and an arrow Z indicates the vertical direction.

First, a radiography apparatus according to the first embodiment of the present disclosure will be described with reference to <FIG>.

A radiography apparatus <NUM> according to this embodiment illustrated in <FIG> is an apparatus that captures a radiographic image of a subject H. The radiography apparatus <NUM> can capture, for example, moving images and still images of the subject H. The capture of the moving image is performed, for example, in a case in which a treatment target part of the subject H is displayed as a moving image during surgery (also referred to as fluoroscopy). In the capture of the moving image, for example, the moving image of the subject H is displayed on a monitor (not illustrated) that is provided separately from the radiography apparatus <NUM>. Of course, data of the captured moving image may be stored in a memory of the radiography apparatus <NUM>. In addition, in the case of the capture of the still image, the captured still image may be displayed on the monitor or may be stored in the memory of the radiography apparatus <NUM>.

As illustrated in <FIG>, the radiography apparatus <NUM> includes an arm <NUM> (referred to as a C-arm or the like) having a C-shape (an arc shape) in a side view and a main body <NUM> to which a connection portion <NUM> is attached. Hereinafter, it is assumed that the side of the radiography apparatus <NUM> on which the arm <NUM> is provided is the front side of the radiography apparatus <NUM> and the side on which the main body <NUM> is provided is the rear side of the radiography apparatus <NUM>.

The arm <NUM> has two ends. An irradiation unit <NUM> is provided at one end of the arm <NUM> and an image receiving unit <NUM> is provided at the other end. The arm <NUM> can hold the irradiation unit <NUM> and the image receiving unit <NUM> in a posture in which they face each other. A space, into which the subject H and a bed S on which the subject H lies supine can be inserted, is ensured between the irradiation unit <NUM> and the image receiving unit <NUM>. In the following description, in some cases, in a side view of the arm <NUM> (as viewed from the Y direction in <FIG>), a direction in which the irradiation unit <NUM> and the image receiving unit <NUM> are provided on the basis of the arm <NUM> is referred to as the front side of the arm <NUM> and the side of the arm <NUM> is referred to as the rear side of the arm <NUM>.

The arm <NUM> can be rotated by a manual operation. Specifically, as illustrated in <FIG>, the arm <NUM> can be orbitally rotated about an axis line M (an axis line parallel to the Y axis) with respect to the connection portion <NUM> by a first rotation mechanism <NUM> which is an example of a displacement mechanism. Further, the arm <NUM> can be rotated about an axis line N (an axis line parallel to the X-axis) with respect to the main body <NUM> by a second rotation mechanism <NUM> which is an example of the displacement mechanism. In this embodiment, the connection portion <NUM> or the main body <NUM> corresponds to a "support portion" that supports the arm <NUM>.

The first rotation mechanism <NUM> comprises a track portion 22B that is provided in the connection portion <NUM> and a fitting portion 22A that is formed on an outer peripheral surface of the arm <NUM> and is fitted to the track portion 22B. The first rotation mechanism <NUM> further comprises a pulley shaft <NUM> as a first rotation shaft, which will be described below, and a belt <NUM>.

The fitting portion 22A has an arc shape following the shape of the arm <NUM>. The track portion 22B has an arc shape that has the same radius as the arc of the arm <NUM> and supports the arm <NUM> so as to be movable along the arc shape. As illustrated in <FIG>, the track portion 22B has, for example, a groove shape and the fitting portion 22A having a convex shape is fitted to the track portion 22B. A roller (not illustrated) that assists the sliding of the fitting portion 22A with respect to the track portion 22B is interposed between the track portion 22B and the fitting portion 22A.

The fitting portion 22A formed in the arm <NUM> slides along the track portion 22B formed in the connection portion <NUM> such that the arm <NUM> can be orbitally rotated about the axis line M at the center of the arc of the arm <NUM> as a rotation center with respect to the connection portion <NUM> and the main body <NUM>.

That is, as illustrated in <FIG> and <FIG>, it is possible to orbitally rotate the arm <NUM> about the axis line M in the direction of an arrow M1 (counterclockwise in <FIG>) and the direction of an arrow M2 (clockwise in <FIG>). Therefore, it is possible to rotate the irradiation unit <NUM> and the image receiving unit <NUM> provided at both ends of the arm <NUM> about the body axis (an axis parallel to the Y axis) of the subject H (see <FIG>).

As illustrated in <FIG>, the second rotation mechanism <NUM> comprises a support shaft <NUM> as a second rotation shaft, one end of which is fixed to the arm <NUM>, and a bearing <NUM> which is provided in the main body <NUM>. The support shaft <NUM> extends in the front-rear direction (X direction) of the radiography apparatus <NUM> and has the other end that is supported by the main body <NUM> through the bearing <NUM>.

The support shaft <NUM> is rotated about the axis line N with respect to the bearing <NUM> such that the arm <NUM> and the connection portion <NUM> are rotatable about the axis line N of the support shaft <NUM> with respect to the main body <NUM> as illustrated in <FIG>.

That is, as illustrated in <FIG> and <FIG>, it is possible to rotate the arm <NUM> about the axis line N in the direction of an arrow N1 (counterclockwise in <FIG>) and the direction of an arrow N2 (clockwise in <FIG>). Therefore, it is possible to reverse the positions of the irradiation unit <NUM> and the image receiving unit <NUM> provided at both ends of the arm <NUM> with respect to the subject H (see <FIG>) in the vertical direction (Z-axis direction).

Here, the posture of the arm <NUM> in which the irradiation unit <NUM> is disposed above the image receiving unit <NUM> as illustrated in <FIG> is also referred to as an overtube posture since a radiation tube <NUM> (see <FIG>) included in the irradiation unit <NUM> is located above the subject H. In contrast, the posture of the arm <NUM> in which the irradiation unit <NUM> is disposed below the image receiving unit <NUM> illustrated in <FIG> is referred to as an undertube posture since the radiation tube <NUM> is located below the subject H.

In the overtube posture, it is possible to increase a distance between the irradiation unit <NUM> and the subject H (see <FIG>) and thus to capture an image of a relatively wide region, as compared to the undertube posture. Therefore, the overtube posture is mainly used to capture the still image of the subject H. In contrast, in the undertube posture, since the radiation emitted from the irradiation unit <NUM> is partially shielded by, for example, the bed S, it is possible to reduce the amount of radiation exposure of a surgeon or an operator (not illustrated) around the subject H (see <FIG>). Therefore, the undertube posture is used for the capture of the moving image of the subject H in which radiation is continuously emitted.

As illustrated in <FIG>, a plurality of casters <NUM> are attached to a lower portion of the main body <NUM> of the radiography apparatus <NUM> and the operator can push the radiography apparatus <NUM> with hands to move the radiography apparatus <NUM> into, for example, an operating room or a hospital ward. That is, the radiography apparatus <NUM> according to this embodiment is a mobile type.

Further, the main body <NUM> includes a control unit <NUM> that controls each unit of the radiography apparatus <NUM>, such as the irradiation unit <NUM>, and an operation panel <NUM> that is, for example, a touch panel type. In addition, the main body <NUM> comprises various switches (not illustrated) including, for example, a power switch of the radiography apparatus <NUM>, a power supply circuit that supplies power to each unit of the radiography apparatus <NUM>, and a battery.

The operation panel <NUM> functions as an operation unit that inputs an operation command to each unit of the radiography apparatus <NUM> to operate each unit and a display unit that displays various kinds of information, such as a warning message and a radiographic image output from the image receiving unit <NUM>.

The control unit <NUM> transmits a control signal to the radiation tube <NUM> of the irradiation unit <NUM>, which will be described below, to control, for example, the tube voltage, tube current, and irradiation time of radiation of the radiation tube <NUM>. The tube voltage is controlled to control the energy of radiation and the tube current and the irradiation time are controlled to control the dose of radiation. In practice, since a high voltage is applied to the radiation tube <NUM>, the control unit <NUM> controls the radiation tube <NUM> through a high-voltage generation device (not illustrated). In imaging, imaging conditions including, for example, the tube voltage, the tube current, and the irradiation time are set through the operation panel <NUM>. The control unit <NUM> operates the irradiation unit <NUM> on the basis of the set imaging conditions.

The control unit <NUM> directs the irradiation unit <NUM> to perform moving image capture irradiation in which the irradiation unit <NUM> continuously emits radiation such that a moving image of the subject H can be captured. In a case in which a moving image is captured, the control unit <NUM> operates a detector of the image receiving unit <NUM> which will be described below in synchronization with the moving image capture irradiation by the irradiation unit <NUM>. In the case of the capture of a moving image, basically, the irradiation time is not set as the imaging condition and commands to start and end the capture of a moving image are input through the operation panel <NUM>. In a case in which the command to start the capture of a moving image is input, the control unit <NUM> directs the irradiation unit <NUM> to start the emission of radiation under preset imaging conditions.

In the capture of a moving image, the detector repeats an image detection operation at a preset frame rate while the moving image capture irradiation is performed. The image output by the detector is transmitted to the control unit <NUM>. The control unit <NUM> sequentially outputs the received images to a monitor (not illustrated). Therefore, the moving image of the subject H is displayed on the monitor.

In addition, the control unit <NUM> directs the irradiation unit <NUM> to perform still image capture irradiation in which the irradiation unit <NUM> emits radiation for a shorter time than in the moving image capture irradiation such that a still image of the subject H can be captured.

In the capture of a still image, the control unit <NUM> operates the detector of the image receiving unit <NUM> in synchronization with the irradiation timing in the still image capture irradiation by the irradiation unit <NUM>. For example, a command to capture a still image is input through an irradiation switch (not illustrated) that is connected to the control unit <NUM>. In the capture of a still image, the irradiation time is, for example, in the order of several tens of milliseconds to several hundreds of milliseconds. In a case in which a command to capture a still image is input, the control unit <NUM> operates the irradiation unit <NUM> on the basis of preset imaging conditions. In the capture of a still image, since the irradiation time is set in the imaging conditions, the irradiation by the irradiation unit <NUM> ends in a case in which the set irradiation time elapses.

In a case in which the irradiation ends, the detector starts to output the detected image. The image output by the detector is transmitted to the control unit <NUM>. The control unit <NUM> stores data of the still image in a memory (not illustrated). Then, the stored still image is displayed on the monitor (not illustrated). Therefore, the still image of the subject H is displayed on the monitor. Further, the still image may be displayed on the operation panel <NUM> in order to check the captured still image immediately after imaging.

The irradiation unit <NUM> comprises a radiation source <NUM> and an irradiation field limiter <NUM>. The radiation source <NUM> comprises the radiation tube <NUM> that generates radiation. The radiation is, for example, X-rays. The radiation tube <NUM> generates radiation by colliding electrons generated from a cathode with a target (anode). The position where the electrons collide with the target is a focus where radiation is emitted.

The irradiation field limiter <NUM> is provided below the radiation source <NUM>. The irradiation field limiter <NUM> (also referred to as a collimator or the like) has a rectangular irradiation opening 34A. The radiation generated by the radiation tube <NUM> is emitted to the subject H through the irradiation opening 34A. The irradiation field limiter <NUM> can adjust the opening area of the irradiation opening 34A. The irradiation field limiter <NUM> has, for example, four shielding plates (not illustrated) that shield radiation. In each of the four shielding plates, each side corresponds to each side of the irradiation opening 34A and defines the irradiation opening 34A. The position of the shielding plates is changed to adjust the opening area of the irradiation opening 34A and the irradiation field of the radiation emitted from the irradiation unit <NUM> is changed.

Further, the irradiation unit <NUM> can be rotated about an axis line of a rotation shaft <NUM> that extends in the width direction of the radiography apparatus <NUM> (the Y direction in <FIG>) as a rotation center with respect to the arm <NUM>. Specifically, a pair of attachment plates <NUM> (one attachment plate is illustrated in <FIG>) are fixed to one end of the arm <NUM>.

The pair of attachment plates <NUM> are disposed such that both sides of the irradiation unit <NUM> in the width direction are interposed therebetween and are connected to both side surfaces of the irradiation unit <NUM> in the width direction. The rotation shafts <NUM> are provided on each of the side surfaces of the irradiation unit <NUM> facing the attachment plates <NUM> so as to protrude. The rotation shafts <NUM> are supported by the pair of attachment plates <NUM> through bearings (not illustrated). Therefore, the irradiation unit <NUM> can be rotated about the axis line of the rotation shaft <NUM> as the rotation center with respect to the attachment plates <NUM> and the orientation of the irradiation opening 34A of the irradiation unit <NUM> can be changed in the front-rear direction of the arm <NUM>. The orientation of the irradiation opening 34A is changed to change the irradiation direction of radiation.

The irradiation unit <NUM> is connected to one end of each of a plurality of cables <NUM> including a signal line for transmitting a control signal and a power line for supplying power. As illustrated in <FIG>, the cables <NUM> are provided in a hollow portion <NUM> that is formed in the arm <NUM> and extend along the arm <NUM>. The other end of the cable <NUM> is connected to, for example, the control unit <NUM> and a power supply circuit (not illustrated) of the main body <NUM> illustrated in <FIG>.

As illustrated in <FIG>, the image receiving unit <NUM> is provided at the other end of the arm <NUM> which is a position facing the irradiation unit <NUM>. The image receiving unit <NUM> is configured by providing the detector in a housing fixed to the arm <NUM> so as not to be detachable from the housing. The image receiving unit <NUM> has an image receiving surface 20A that receives the radiation which has been emitted from the irradiation unit <NUM> and then transmitted through the subject H. The radiation carrying the information of the subject H is incident on the image receiving surface 20A.

The detector is, for example, a flat panel detector (FPD) of a digital radiography (DR) type. The FPD has a detection surface in which a plurality of pixels are two-dimensionally arranged and a thin film transistor (TFT) panel (not illustrated) 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 electric signal and outputs a radiographic image indicating the subject H on the basis of the converted electric signal. For example, the detector is an indirect conversion type that converts radiation into visible light using a scintillator and converts the converted visible light into an electric signal. In addition, the detector may be a direct conversion type that directly converts radiation into an electric signal. Further, the image receiving unit <NUM> may have, for example, a configuration in which an image intensifier (I. I) and a camera are combined other than the configuration using the FPD.

Further, the image receiving unit <NUM> is connected to, for example, the control unit <NUM> and the power supply circuit (not illustrated) of the main body <NUM> by a cable (not illustrated) including a signal line for transmitting a control signal and a power line for supplying power.

As illustrated in <FIG>, the connection portion <NUM> of the radiography apparatus <NUM> is provided with a friction mechanism <NUM> that applies a frictional force to the arm <NUM> in a direction opposite to the direction in which the arm <NUM> is displaced.

Specifically, both ends of the belt <NUM> forming the first rotation mechanism <NUM> are fixed to both ends of the arm <NUM>, respectively. The arm <NUM> is a hollow cylindrical body. As illustrated in <FIG>, the belt <NUM> and the cables <NUM> are provided in the hollow portion <NUM> of the arm <NUM>. In the hollow portion <NUM>, a groove 42A that extends along the arc of the arm <NUM> is formed in the front inner surface of the arm <NUM>. The belt <NUM> extends along the arc of the arm <NUM> while being accommodated in the groove 42A. Therefore, it is possible to suppress interference between the cables <NUM> and the belt <NUM> in the hollow portion <NUM> of the arm <NUM>.

As illustrated in <FIG> and <FIG>, the connection portion <NUM> is provided with the pulley shaft <NUM> forming the first rotation mechanism <NUM>. As illustrated in <FIG>, the pulley shaft <NUM> is supported by a frame <NUM> of the connection portion <NUM> through a bearing portion <NUM> so as to be rotatable. A pulley <NUM> is fixed to the pulley shaft <NUM> so as to be coaxially rotatable and the belt <NUM> is wound around the pulley <NUM>.

As illustrated in <FIG>, the belt <NUM> is a timing belt having a plurality of teeth 46A formed thereon. The pulley <NUM> is a timing pulley having a plurality of grooves 54A formed in an outer peripheral surface. The teeth 46A of the belt <NUM> are engaged with the grooves 54A of the pulley <NUM> such that the belt <NUM> and the pulley <NUM> are operatively associated with each other.

Further, as illustrated in <FIG>, idlers <NUM> are provided above and below the pulley <NUM> in the vertical direction (Z direction) in the connection portion <NUM>, respectively. The belt <NUM> is guided by a pair of idlers <NUM> while being kept at a predetermined tension and is wound around the pulley <NUM>.

In a case in which the arm <NUM> is orbitally rotated with respect to the track portion 22B, the belt <NUM> follows the movement of the arm <NUM>. For example, in a case in which one end of the arm <NUM> is moved in a direction in which it becomes further away from the connection portion <NUM> (track portion 22B), the belt <NUM> is moved in the direction of an arrow P in <FIG>, that is, in a direction in which the one end becomes further away from the connection portion <NUM>. In this case, the pulley <NUM> engaged with the belt <NUM> is also rotated in the direction of an arrow Q (clockwise in <FIG>) following the movement of the belt <NUM>.

A first gear <NUM> is fixed to the pulley shaft <NUM> so as to be rotatable coaxially with the pulley <NUM>. A second gear <NUM> is engaged with the first gear <NUM> and the friction mechanism <NUM> is connected to the second gear <NUM>. The friction mechanism <NUM> includes a friction shaft <NUM>, a frictional force generation unit <NUM> that is attached to the friction shaft <NUM> and generates a frictional force, and a clutch <NUM> that switches connection and disconnection between the pulley shaft <NUM> and the friction shaft <NUM>.

As illustrated in <FIG>, the friction shaft <NUM> is supported by the frame <NUM> of the connection portion <NUM> through a bearing <NUM> so as to be rotatable. The friction shaft <NUM> is inserted into a shaft hole 70A that is formed in a side plate <NUM>. The side plate <NUM> is fixed to the frame <NUM> at a distance from the frame <NUM> in the axial direction of the friction shaft <NUM> (the Y direction in <FIG>).

The frictional force generation unit <NUM> comprises two sets of friction plates 72A and 72B that generate a frictional force using contact between friction surfaces, and a biasing portion <NUM> that biases the friction plates 72A and 72B in a direction in which the friction surfaces are pressed. The two sets of friction plates 72A and 72B are provided on both end surfaces of the side plate <NUM> in the axial direction of the friction shaft <NUM>, respectively.

A shaft holes (not illustrated) is formed in each of the friction plates 72A and 72B. The friction shaft <NUM> is inserted into the shaft holes such that the friction plates 72A and 72B are attached so as to be movable in the axial direction of the friction shaft <NUM>. The movement of one set of friction plates 72A and 72B, which is disposed between the side plate <NUM> and the frame <NUM>, in the axial direction of the friction shaft <NUM> is regulated by a regulation plate <NUM> that is fixed to the friction shaft <NUM>.

The friction plate 72A that comes into contact with the end surface of the side plate <NUM> is fixed by a rotation stopper (not illustrated), and is a fixed friction plate that is not rotated regardless of the rotation of the friction shaft <NUM>. In contrast, the friction plate 72B that is provided outside the friction plate 72A (fixed friction plate) in the axial direction of the friction shaft <NUM> with respect to the side plate <NUM> is a rotary friction plate that is rotated as the friction shaft <NUM> is rotated.

The biasing portion <NUM> is provided between the side plate <NUM> and one end of the friction shaft <NUM> in the axial direction. The biasing portion <NUM> comprises a disc spring unit <NUM>, a pair of buffer plates <NUM>, and a nut <NUM> that is provided at one end of the friction shaft <NUM> in the axial direction.

The disc spring unit <NUM> includes a plurality of disc springs 78A. The disc spring 78A is a disk-shaped spring that has one convex surface and the other concave surface. The plurality of disc springs 78A are arranged along the axial direction of the friction shaft <NUM> so as to be stacked.

Further, each of the buffer plates <NUM> is disposed outside the disc spring units <NUM> in the axial direction of the friction shaft <NUM>. One buffer plate <NUM> is disposed between the disc spring unit <NUM> and the friction plate 72B. The other buffer plate <NUM> is disposed between the disc spring unit <NUM> and the nut <NUM>. A shaft hole (not illustrated) is formed in each of the buffer plate <NUM> and the disc spring 78A. The friction shaft <NUM> is inserted into the shaft holes such that the buffer plate <NUM> and the disc spring 78A are attached so as to be movable in the axial direction of the friction shaft <NUM>.

In a case in which the nut <NUM> is tightened with the end surface of the disc spring unit <NUM> in contact with one buffer plate <NUM>, the disc spring unit <NUM> is moved in the direction in which the one buffer plate <NUM> is pressed. In a case in which the disc spring unit <NUM> is moved, a pressing force is applied to each set of the friction plates 72A and 72B through the buffer plate <NUM>. In a case in which the nut <NUM> is further tightened and the disc spring unit <NUM> reaches a movement limit, the disc spring 78A is elastically deformed and the disc spring unit <NUM> contracts in the axial direction of the friction shaft <NUM>. The disc spring unit <NUM> biases the friction surfaces of the friction plates 72A and 72B in a direction in which they are pressed against each other on the basis of elasticity.

As such, the operation of the biasing portion <NUM> causes the friction surfaces of the friction plates 72A and 72B to come into contact with each other and a normal force is generated on the friction surfaces. Therefore, in a case in which the friction shaft <NUM> is rotated, a frictional force acts on the friction surfaces of the friction plates 72A and 72B in a direction opposite to a rotation direction of the friction shaft <NUM>.

The clutch <NUM> is attached to the other end of the friction shaft <NUM> in the axial direction. In this embodiment, the clutch <NUM> is an electromagnetic clutch and includes a housing <NUM> having an electromagnet (not illustrated) provided therein and a shaft fixing portion <NUM> fixed to the friction shaft <NUM>. The housing <NUM> and the shaft fixing portion <NUM> are separated from each other. Further, a biasing member (not illustrated) that biases the housing <NUM> and the shaft fixing portion <NUM> in the direction in which they become further away from each other is provided between the housing <NUM> and the shaft fixing portion <NUM>.

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

The clutch <NUM> switches connection and disconnection between the second gear <NUM> and the friction shaft <NUM> to switch connection and disconnection between the pulley shaft <NUM> and the friction shaft <NUM>. Specifically, in a case in which the clutch <NUM> is energized, a magnetic force is generated in the electromagnet provided in the housing <NUM> and the shaft fixing portion <NUM> is attracted to the electromagnet against the biasing force of the biasing member (not illustrated). Therefore, the housing <NUM> and the shaft fixing portion <NUM> are closely connected.

In a case in which the pulley shaft <NUM> is rotated in a state in which the housing <NUM> is connected to the shaft fixing portion <NUM> (corresponding to a first state), the first gear <NUM>, the second gear <NUM>, and the housing <NUM> of the clutch <NUM> are rotated with the rotation of the pulley shaft <NUM>. The shaft fixing portion <NUM> of the clutch <NUM> connected to the housing <NUM> and the friction shaft <NUM> to which the shaft fixing portion <NUM> is fixed are also rotated with the rotation of the pulley shaft <NUM>.

As described above, since the frictional force in the direction opposite to the rotation direction acts on the friction shaft <NUM>, the friction shaft <NUM> is rotated with the rotation of the pulley shaft <NUM> and the frictional force acts on the pulley shaft <NUM> in the direction opposite to the rotation direction. The pulley <NUM> is fixed to the pulley shaft <NUM> and the belt <NUM> fixed to both ends of the arm <NUM> illustrated in <FIG> is wound around the pulley <NUM>.

Therefore, a frictional force acts on the pulley shaft <NUM> in a direction opposite to the rotation direction. In a case in which the arm <NUM> is orbitally rotated with respect to the track portion 22B (see <FIG>), a frictional force acts on the arm <NUM> in a direction opposite to the rotation direction of the arm <NUM>.

In contrast, in a case in which the clutch <NUM> is de-energized, the housing <NUM> fixed to the second gear <NUM> and the shaft fixing portion <NUM> fixed to the friction shaft <NUM> are biased by a biasing member (not illustrated) and are separated from each other. Therefore, the housing <NUM> and the shaft fixing portion <NUM> are disconnected and the second gear <NUM> and the friction shaft <NUM> are disconnected.

In a case in which the pulley shaft <NUM> is rotated in a state in which the housing <NUM> and the shaft fixing portion <NUM> are disconnected (corresponding to a second state), the first gear <NUM>, the second gear <NUM>, and the housing <NUM> of the clutch <NUM> are rotated with the rotation of the pulley shaft <NUM>. However, the shaft fixing portion <NUM> of the clutch <NUM> and the friction shaft <NUM> are not rotated. Therefore, the frictional force that acts on the friction shaft <NUM> in a case in which the pulley shaft <NUM> is rotated does not act. The frictional force that acts on the arm <NUM> in a case in which the arm <NUM> is orbitally rotated is less than that in a case in which the clutch <NUM> is energized.

The operator operates the operation panel <NUM> (see <FIG>) as an operation unit to perform the switching between the first state and the second state of the friction mechanism <NUM>. For example, in a case in which the operator inputs an operation command to switch the friction mechanism <NUM> to the first state to the operation panel <NUM>, the control unit <NUM> (see <FIG>) transmits a driving signal to the clutch <NUM> to energize the clutch <NUM>. Therefore, the housing <NUM> and the shaft fixing portion <NUM> of the clutch <NUM> are connected to each other to switch the friction mechanism <NUM> to the first state in which the frictional force acts on the arm <NUM>.

In contrast, in a case in which the operator inputs an operation command to switch the friction mechanism <NUM> to the second state to the operation panel <NUM>, the control unit <NUM> (see <FIG>) de-energizes the clutch <NUM>. Therefore, the housing <NUM> and the shaft fixing portion <NUM> of the clutch <NUM> are disconnected from each other to switch the friction mechanism <NUM> to the second state in which the frictional force does not act on the arm <NUM>.

The radiography apparatus <NUM> according to this embodiment comprises the first rotation mechanism <NUM> (an example of the displacement mechanism) that rotates the arm <NUM> with respect to the connection portion <NUM> and the friction mechanism <NUM> that applies a frictional force to the arm <NUM> in a direction opposite to the direction in which the arm <NUM> is rotated by the first rotation mechanism <NUM>.

Further, the friction mechanism <NUM> can be switched between the first state in which a frictional force is applied to the arm <NUM> in the direction opposite to the direction in which the arm <NUM> is displaced and the second state in which the frictional force applied to the arm <NUM> is less than that in the first state. Therefore, the friction mechanism <NUM> is switched between the first state and the second state to change a load due to the manual operation force of the arm <NUM> in a case in which the arm <NUM> is manually rotated.

In particular, according to this embodiment, the arm <NUM> may not be rotated by an electromotive force, but may be rotated by only a manual operation. Therefore, it is possible to reduce the size and weight of the entire radiography apparatus <NUM>. In many cases, a large-sized radiography apparatus includes a mechanism that electrically displaces the arm. In general, in the large-sized apparatus, the operation force of the arm is controlled through a complicated mechanism such as an electric mechanism.

Here, according to this embodiment, even in a case in which the arm <NUM> is rotated by only a manual operation to reduce the size and weight of the radiography apparatus <NUM>, the friction mechanism <NUM> can switch the operation force of the arm <NUM> with a relatively simple structure. Therefore, the technology of this embodiment is particularly effective for the radiography apparatus <NUM> with a small size and weight in which the arm <NUM> is rotated by only a manual operation.

Further, according to this embodiment, the first rotation mechanism <NUM> has the pulley shaft <NUM> that is rotated as the arm <NUM> is rotated. Then, the friction mechanism <NUM> comprises the friction shaft <NUM>, the frictional force generation unit <NUM> that is attached to the friction shaft <NUM> and generates a frictional force, and the clutch <NUM> that switches connection and disconnection between the pulley shaft <NUM> and the friction shaft <NUM>.

As described above, the operative association between the components of the first rotation mechanism <NUM> and the components of the friction mechanism <NUM> makes it possible to reduce the size of each mechanism, as compared to a case in which the first rotation mechanism <NUM> and the friction mechanism <NUM> are independently configured.

In particular, according to this embodiment, the first rotation mechanism <NUM> has the pulley shaft <NUM> to which the pulley <NUM> is fixed and the belt <NUM> which has both ends fixed to both ends of the arm <NUM> and is wound around the pulley <NUM>. As such, since the belt <NUM> fixed to both ends of the arm <NUM> is wound around the pulley <NUM> fixed to the pulley shaft <NUM>, it is possible to operatively associate the components of the first rotation mechanism <NUM> with the components of the friction mechanism <NUM> even in a case in which the arm <NUM> is orbitally rotated.

Further, as a modification example of the first rotation mechanism <NUM>, a rack and pinion system or a system in which a chain and a sprocket are combined are considered instead of the belt <NUM>. However, in a case in which the belt <NUM> is used, the weight of the apparatus can be less than that in these systems.

Further, in addition to the first rotation mechanism <NUM> and the second rotation mechanism <NUM>, for example, a slide mechanism that slides the arm <NUM> in the horizontal direction (X direction) with respect to the main body <NUM> is considered as the displacement mechanism for displacing the arm <NUM>. However, in general, in the operation of rotating the arm <NUM>, a load is less than that in the operation of sliding the arm <NUM> in the horizontal direction. Therefore, the friction mechanism <NUM> according to this embodiment which can switch the frictional force is particularly effective in a case in which the friction mechanism <NUM> is combined with the first rotation mechanism <NUM> or the second rotation mechanism <NUM>.

That is, it is possible to prevent the arm <NUM> from being inadvertently rotated by switching the friction mechanism <NUM> to the first state. On the other hand, it is possible to reduce the load in a case in which the arm <NUM> is manually rotated by switching the friction mechanism <NUM> to the second state.

Further, according to this embodiment, the operator operates the operation panel <NUM> as the operation unit to perform the switching between the first state and the second state by the friction mechanism <NUM>. That is, the operator can optionally switch the frictional force.

Therefore, for example, in a case in which a moving image is captured by the radiography apparatus <NUM> during surgery, the frictional force is reduced such that positioning is performed with a small force in a preparatory stage before surgery. During surgery, the frictional force is increased to prevent the arm <NUM> from being inadvertently rotated due to the application of an unintended external force to the arm <NUM> such as the collision of the operator with the arm <NUM>.

Next, a radiography apparatus according to a the invention will be described with reference to <FIG>. In addition, the same configurations as those in the first embodiment are denoted by the same reference numerals and the description thereof will not be repeated. The description is focused on the differences between the first and second embodiments.

In the radiography apparatus <NUM> according to the first embodiment, the image receiving unit <NUM> is fixed to the other end of the arm <NUM>. In contrast, as illustrated in <FIG>, in a radiography apparatus <NUM> according to this embodiment, an image receiving unit <NUM> is a portable type that is attached to the arm <NUM> so as to be detachable. In the image receiving unit <NUM>, a detector is provided in a housing so as not to be detachable as in the first embodiment. The portable image receiving unit <NUM> is called, for example, an electronic cassette.

Specifically, the image receiving unit <NUM> is attached to a base <NUM> that is provided at the other end of the arm <NUM> so as to be detachable. The base <NUM> is provided on the upper surface of the other end of the arm <NUM> and a fitting convex portion <NUM> is provided uprightly on the base <NUM>. Each of the base <NUM> and the fitting convex portion <NUM> has a rectangular parallelepiped shape and the width (length in the Y direction) of the fitting convex portion <NUM> is smaller than the width (length in the Y direction) of the base <NUM>.

The image receiving unit <NUM> has a flat rectangular parallelepiped shape. A fitting concave portion <NUM> that is fitted to the fitting convex portion <NUM> is formed in the lower surface of the image receiving unit <NUM>. The fitting concave portion <NUM> has a rectangular parallelepiped shape and the length (length in the Y direction in <FIG>) of the fitting concave portion <NUM> in the lateral direction is larger than the width of the fitting convex portion <NUM> and is smaller than the width of the base <NUM>. Further, the height of the fitting concave portion <NUM> is substantially equal to the height of the fitting convex portion <NUM>.

In addition, the length (length in the X direction in <FIG>) of the fitting concave portion <NUM> in the longitudinal direction is larger than the length (length in the X direction) of the base <NUM> and the fitting convex portion <NUM>. One end of the fitting concave portion <NUM> in the longitudinal direction extends to one side surface of the image receiving unit <NUM>. Since one end of the fitting concave portion <NUM> is located on one side surface of the image receiving unit <NUM>, a part of one side surface of the image receiving unit <NUM> is open.

In a case in which the image receiving unit <NUM> is attached to the arm <NUM>, the image receiving unit <NUM> is moved in the horizontal direction (X direction) such that the fitting convex portion <NUM> that is provided uprightly on the base <NUM> is inserted into the fitting concave portion <NUM> through the opening formed in one side surface of the image receiving unit <NUM>. Then, the lower surface of the image receiving unit <NUM> comes into contact with the upper surface of the base <NUM> in a state in which the fitting convex portion <NUM> is fitted to the fitting concave portion <NUM>.

Here, a pair of positioning pins <NUM> that protrude into the fitting concave portion <NUM> are provided on the other end surface of the fitting concave portion <NUM> in the longitudinal direction. A pair of pin holes <NUM> into which the positioning pins <NUM> are inserted are formed in one side surface of the fitting convex portion <NUM> which faces the other end surface of the fitting concave portion <NUM> in the longitudinal direction in a case in which fitting convex portion <NUM> is fitted to the fitting concave portion <NUM>.

In a case in which the fitting concave portion <NUM> of the image receiving unit <NUM> is fitted to the fitting convex portion <NUM>, the pair of positioning pins <NUM> are inserted into the pair of pin holes <NUM> such that the image receiving unit <NUM> is positioned and attached to the base <NUM>, that is, the other end of the arm <NUM>.

A through hole <NUM> that extends in the vertical direction (Z direction) is formed in the upper surface of the base <NUM> and a solenoid <NUM> is provided below the through hole <NUM> at the other end of the arm <NUM>. An insertion hole <NUM> having substantially the same diameter as the through hole <NUM> is formed in the lower surface of the image receiving unit <NUM>. Here, as illustrated in <FIG>, the insertion hole <NUM> of the image receiving unit <NUM> is formed at a position that communicates with the through hole <NUM> of the base <NUM> in a case in which the image receiving unit <NUM> is positioned and attached to the base <NUM>.

The solenoid <NUM> comprises a movable iron core 116A that is inserted into the through hole <NUM>. The movable iron core 116A can be expanded and contracted by switching between an energized state and a non-energized state of the solenoid <NUM>.

Specifically, in a case in which the solenoid <NUM> is energized, the movable iron core 116A is attracted to the main body of the solenoid <NUM> and a leading end of the movable iron core 116A is located in the through hole <NUM> of the base as illustrated in <FIG>. In this state, since the movable iron core 116A is not inserted into the insertion hole <NUM> of the image receiving unit <NUM>, the image receiving unit <NUM> is attachable to and detachable from the base <NUM>, that is, the arm <NUM>.

In contrast, in a state in which the insertion hole <NUM> of the image receiving unit <NUM> and the through hole <NUM> of the base <NUM> communicate with each other, that is, in a state in which the image receiving unit <NUM> is positioned and attached to the other end of the arm <NUM>, the movable iron core 116A can be inserted into the insertion hole <NUM> of the image receiving unit <NUM> as illustrated in <FIG>.

Therefore, in a case in which the solenoid <NUM> is de-energized in a state in which the image receiving unit <NUM> is positioned and attached to the other end of the arm <NUM>, the leading end of the movable iron core 116A is inserted into the insertion hole <NUM> and reaches the image receiving unit <NUM>. In this state, since the movable iron core 116A of the solenoid <NUM> is also inserted into the insertion hole <NUM> of the image receiving unit <NUM>, the detachment of the image receiving unit <NUM> from the base <NUM>, that is, the arm <NUM> is regulated. As described above, the solenoid <NUM> forms an attachment and detachment regulation mechanism that regulates the inadvertent attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> in a state in which the image receiving unit <NUM> is attached to the arm <NUM>.

Further, the base <NUM> is provided with a photo sensor <NUM> as an attachment and detachment detection unit that detects whether or not the image receiving unit <NUM> is detached from the arm <NUM>. The photo sensor <NUM> is, for example, a reflective sensor in which a light emitting window through which a light emitting element (not illustrated) emits light and a light receiving window through which a light receiving element (not illustrated) receives light are arranged on the same surface. The photo sensor <NUM> is provided at a position where the light emitting window and the light receiving window are exposed to the outside in a state in which the image receiving unit <NUM> is not attached to the base <NUM> and the image receiving unit <NUM> covers the light emitting window and the light receiving window in a state in which the image receiving unit <NUM> is attached to the base <NUM>. For example, the photo sensor <NUM> according to this example is disposed on the base <NUM> in a posture facing the upper surface in <FIG>.

For example, in a case in which the base <NUM> is attached to the image receiving unit <NUM>, in the photo sensor <NUM>, the light emitted from the light emitting window is reflected by the image receiving unit <NUM> such that the amount of light received through the light receiving window increases. In contrast, in a state in which the image receiving unit <NUM> is detached from the base <NUM> and is retracted from the front surfaces of the light emitting window and the light receiving window, light is not reflected from the image receiving unit <NUM> and the amount of light received through the light receiving window is reduced.

As such, the photo sensor <NUM> detects a change in the light which has been emitted from the light emitting window and then received by the light receiving element to detect whether or not the image receiving unit <NUM> is detached from the arm <NUM>.

The photo sensor <NUM> outputs an on signal as a detection signal to a control unit <NUM> illustrated in <FIG> in a state in which it is detected that the image receiving unit <NUM> is attached to the arm <NUM> and outputs an off signal as the detection signal to the control unit <NUM> illustrated in <FIG> in a state in which it is detected that the image receiving unit <NUM> is detached from the arm <NUM>.

The portable image receiving unit <NUM> has, for example, a battery and a wireless communication unit which are not illustrated and can wirelessly communicate with the control unit <NUM> (see <FIG>) provided in the main body <NUM>. In a case in which a wireless communication unit is used, the image receiving unit <NUM> is driven by power from the battery and can be used in a so-called cableless manner. Therefore, the image receiving unit <NUM> can be used in a state in which it is detached from the arm <NUM>.

In contrast, in a case in which the image receiving unit <NUM> is attached to the arm <NUM>, a terminal 122A that is provided in the fitting concave portion <NUM> of the image receiving unit <NUM> and a terminal 122B that is provided in the fitting convex portion <NUM> of the arm <NUM> illustrated in <FIG> come into contact with each other and the image receiving unit <NUM> and the base <NUM> are electrically connected. Further, the base <NUM> is connected to, for example, the control unit <NUM> (see <FIG>) and a power supply circuit (not illustrated) of the main body <NUM> by a cable (not illustrated) including a signal line for transmitting a control signal and a power line for supplying power. Therefore, in a state in which the image receiving unit <NUM> is attached to the arm <NUM>, the image receiving unit <NUM> is connected to, for example, the control unit <NUM> and the power supply circuit (not illustrated) through a cable (not illustrated).

As illustrated in <FIG> and <FIG>, a connection portion <NUM> of the radiography apparatus <NUM> is provided with the belt <NUM> and the pulley shaft <NUM> forming the first rotation mechanism <NUM> and the friction mechanism <NUM> as in the first embodiment. The pulley <NUM> is fixed to the pulley shaft <NUM> so as to be coaxially rotatable and the belt <NUM> is wound around the pulley <NUM>.

The friction mechanism <NUM> has the same configuration as that in the first embodiment and can be switched between a first state in which a frictional force is applied to the arm <NUM> and a second state in which the frictional force is not applied to the arm <NUM>. Here, in this embodiment, in a case in which the friction mechanism <NUM> is in the first state, the frictional force applied to the arm <NUM> by the friction mechanism <NUM> is set to a value that is greater than at least the maximum weight of the image receiving unit <NUM> that can be attached to the arm <NUM>.

Further, in this embodiment, the connection portion <NUM> of the radiography apparatus <NUM> is provided with an electromagnetic brake <NUM> that locks the rotation of the arm <NUM> by the first rotation mechanism <NUM> in addition to the friction mechanism <NUM>. The electromagnetic brake <NUM> is connected to the pulley shaft <NUM> forming the first rotation mechanism <NUM>.

The electromagnetic brake <NUM> is, for example, a non-excitation operation type, locks rotation in a case in which it is not energized, and unlocks rotation in a case in which it is energized. Since the electromagnetic brake <NUM> of the non-excitation operation type which locks rotation in a case in which it is de-energized is used, the rotation of the arm <NUM> is locked in a case in which the electromagnetic brake <NUM> is de-energized due to, for example, a power failure. Therefore, it is possible to suppress the inadvertent rotation of the arm <NUM>.

Specifically, the electromagnetic brake <NUM> comprises a housing 124A in which an electromagnet (not illustrated) is provided. The pulley shaft <NUM> is attached to the housing 124A through a rotor (not illustrated) that is provided in the housing 124A. The housing 124A is fixed to the connection portion <NUM> so as not to be rotatable. The rotor and the pulley shaft <NUM> are rotatable with respect to the housing 124A.

The electromagnet and the rotor are disposed around the pulley shaft <NUM> so as to face each other in the axial direction of the pulley shaft <NUM>, which is not illustrated. Further, in the housing 124A, a movable iron piece that is movable in the axial direction of the pulley shaft <NUM> is provided between the electromagnet and the rotor. The movable iron piece is disposed so as to be separated from the electromagnet and is biased toward the rotor by a biasing member (not illustrated) to press the rotor against the inner wall surface of the housing 124A.

In a case in which the electromagnetic brake <NUM> is not energized, the movable iron piece presses the rotor against the inner wall surface of the housing 124A so as to come into close contact therewith. Therefore, the rotation of the rotor with respect to the housing 124A is locked. In a case in which the rotation of the rotor with respect to the housing 124A is locked, the rotation of the pulley shaft <NUM> fixed to the rotor and the pulley <NUM> fixed to the pulley shaft <NUM> is locked and the movement of the belt <NUM> engaged with the pulley <NUM> is also locked.

As illustrated in <FIG>, since both ends of the belt <NUM> are fixed to both ends of the arm <NUM>, the orbital rotation of the arm <NUM> with respect to the track portion 22B is locked by the locking of the movement of the belt <NUM>.

In contrast, in a case in which the electromagnetic brake <NUM> is energized, a magnetic force is generated in the electromagnet provided in the housing 124A and the movable iron piece is attracted to the electromagnet against the biasing force of the biasing member. Therefore, 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 be rotated with respect to the housing 124A. That is, the rotation of the rotor is unlocked.

Further, in a case in which the rotation of the rotor is unlocked, the rotation of the pulley shaft <NUM> and the pulley <NUM> is also unlocked and the belt <NUM> engaged with the pulley <NUM> can be moved. Therefore, the orbital rotation of the arm <NUM> illustrated in <FIG> with respect to the track portion 22B is unlocked.

As illustrated in <FIG>, the control unit <NUM> of the radiography apparatus <NUM> controls the solenoid <NUM> provided at the other end of the arm <NUM>.

In a case in which an operation of deregulating attachment and detachment is performed through the operation panel <NUM> (see <FIG>) in a state in which the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> is regulated by the solenoid <NUM>, the control unit <NUM> transmits a driving signal to the solenoid <NUM> to energize the solenoid <NUM>. Then, the movable iron core 116A illustrated in <FIG> is attracted by the solenoid <NUM> and the image receiving unit <NUM> is detachable from the arm <NUM>.

In contrast, in a case in which a command to regulate attachment and detachment is input through the operation panel <NUM> (see <FIG>), the control unit <NUM> de-energizes the solenoid <NUM>. In this case, in a state in which the image receiving unit <NUM> is attached to the arm <NUM>, the insertion hole <NUM> of the image receiving unit <NUM> and the through hole <NUM> of the base <NUM> communicate with each other as illustrated in <FIG>. Therefore, the movable iron core 116A is inserted into the insertion hole <NUM> of the image receiving unit <NUM> to regulate the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM>.

In a case in which the image receiving unit <NUM> is not attached to the arm <NUM>, that is, the insertion hole <NUM> of the image receiving unit <NUM> and the through hole <NUM> of the base <NUM> do not communicate with each other, it is difficult to insert the movable iron core 116A into the insertion hole <NUM> even though a command to regulate attachment and detachment is input. Therefore, the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> is not regulated.

As described above, the control unit <NUM> controls the energization of the solenoid <NUM> to perform switching between a state in which the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> is permitted and a state in which the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> is regulated.

Further, as illustrated in <FIG>, the control unit <NUM> determines whether or not the image receiving unit <NUM> is detached from the arm <NUM> on the basis of a detection signal from the photo sensor <NUM> provided in the arm <NUM>.

That is, in a case in which the image receiving unit <NUM> is attached to the arm <NUM> as illustrated in <FIG>, the control unit <NUM> receives an on signal as the detection signal from the photo sensor <NUM>. The control unit <NUM> determines that the image receiving unit <NUM> is attached to the arm <NUM> while receiving the on signal from the photo sensor <NUM>.

In contrast, in a case in which the image receiving unit <NUM> is detached from the arm <NUM> as illustrated in <FIG>, the control unit <NUM> receives an off signal as the detection signal from the photo sensor <NUM>. The control unit <NUM> determines that the image receiving unit <NUM> is detached from the arm <NUM> while receiving the off signal from the photo sensor <NUM>.

Further, the control unit <NUM> controls the friction mechanism <NUM> provided in the connection portion <NUM> in response to an operation command from the operation panel <NUM>. That is, in a case in which a frictional force switching command is input through the operation panel <NUM>, the control unit <NUM> transmits a driving signal to the clutch <NUM> of the friction mechanism <NUM> illustrated in <FIG> to energize the clutch <NUM>, thereby switching the friction mechanism <NUM> to the first state, as in the first embodiment. In contrast, the control unit <NUM> de-energizes the clutch <NUM> to switch the friction mechanism <NUM> to the second state.

Furthermore, the control unit <NUM> controls the electromagnetic brake <NUM> provided in the connection portion <NUM>. That is, the control unit <NUM> de-energizes the electromagnetic brake <NUM> to lock the rotation of the pulley shaft <NUM> and the pulley <NUM> with respect to the housing 124A of the electromagnetic brake <NUM> illustrated in <FIG>, thereby locking the orbital rotation of the arm <NUM> with respect to the track portion 22B.

In contrast, the control unit <NUM> transmits a driving signal to the electromagnetic brake <NUM> to energize the electromagnetic brake <NUM>. Then, the rotation of the pulley shaft <NUM> with respect to the housing 124A illustrated in <FIG> is unlocked. Thus, the rotation of the pulley <NUM> is unlocked to unlock the orbital rotation of the arm <NUM> with respect to the track portion 22B.

Next, a method for controlling the radiography apparatus <NUM> according to this embodiment will be described with reference to a flowchart illustrated in <FIG>.

First, in Step S500, in a case in which the radiography apparatus <NUM> is turned on by the operation of a power switch (not illustrated) (Y in Step S500), the control unit <NUM> starts to control the radiography apparatus <NUM>. In a case in which the control by the control unit <NUM> is started, it is possible to receive the input of the imaging conditions through the operation panel <NUM>.

In Step S502, the control unit <NUM> determines whether or not the image receiving unit <NUM> is detached from the arm <NUM>. In a case in which it is determined that the image receiving unit <NUM> is detached from the arm <NUM> (Y in Step S502), the control unit <NUM> switches the friction mechanism <NUM> to the first state (Step S504). That is, the clutch <NUM> of the friction mechanism <NUM> illustrated in <FIG> is energized to connect the housing <NUM> and the shaft fixing portion <NUM>.

In a case in which it is determined in Step S502 that the image receiving unit <NUM> is attached to the arm <NUM> (N in Step S502), the control unit <NUM> switches the friction mechanism <NUM> to the second state (Step S506). That is, the clutch <NUM> of the friction mechanism <NUM> illustrated in <FIG> is de-energized to disconnect the housing <NUM> from the shaft fixing portion <NUM>.

In Step S508, the control unit <NUM> determines whether or not the radiography apparatus <NUM> has been turned off by the operation of the power switch (not illustrated) by the operator. Then, in a case in which the radiography apparatus <NUM> has not been turned off (N in Step S508), the process returns to Step S502. On the other hand, in a case in which the radiography apparatus <NUM> has been turned off (Y in Step S508), the control unit <NUM> ends the control of the radiography apparatus <NUM>.

According to the radiography apparatus <NUM> of this embodiment, the friction mechanism <NUM> is connected to the first rotation mechanism <NUM> that rotates the arm <NUM> with respect to the connection portion <NUM>, as in the radiography apparatus <NUM> according to the first embodiment. Therefore, the friction mechanism <NUM> can be switched between the first state and the second state to change a load due to the manual operation force of the arm <NUM>.

Further, in the radiography apparatus <NUM> according to this embodiment, the image receiving unit <NUM> is attached to the arm <NUM> so as to be detachable. In general, in a case in which the arm <NUM> is rotated and the image receiving unit <NUM> is attachable and detachable, the arm <NUM> is likely to be inadvertently rotated due to a great change in weight balance during the detachment of the image receiving unit <NUM>. Therefore, the friction mechanism <NUM> according to this embodiment is particularly effective for the radiography apparatus <NUM> in which the image receiving unit <NUM> is attachable to and detachable from the arm <NUM>.

Further, the radiography apparatus <NUM> according to this embodiment comprises the photo sensor <NUM> as an example of the attachment and detachment detection unit that detects whether or not the image receiving unit <NUM> is detached from the arm <NUM>. In addition, the radiography apparatus <NUM> comprises the control unit <NUM> that performs control to switch the friction mechanism <NUM> to the first state in a case in which the photo sensor <NUM> detects that the image receiving unit <NUM> is detached from the arm <NUM> and to switch the friction mechanism <NUM> to the second state in a case in which the photo sensor <NUM> detects that the image receiving unit <NUM> is attached to the arm <NUM>.

As such, the friction mechanism <NUM> is switched to the first state, that is, the frictional force acting on the arm <NUM> increases in operative association with the detachment of the image receiving unit <NUM>. Therefore, even in a case in which the image receiving unit <NUM> is detached, it is possible to suppress the inadvertent rotation of the arm <NUM>.

Further, according to this embodiment, the frictional force applied to the arm <NUM> by the friction mechanism <NUM> is set to a value that is greater than at least the maximum weight of the image receiving unit <NUM> that can be attached to the arm <NUM>. As such, since the frictional force in the first state of the friction mechanism <NUM> is greater than the weight of the image receiving unit <NUM>, a change in the weight balance of the arm <NUM> in a case in which the image receiving unit <NUM> is detached can be absorbed by the frictional force and it is possible to further suppress the inadvertent rotation of the arm <NUM>.

In addition, according to this embodiment, the radiography apparatus further comprises the electromagnetic brake <NUM> that locks the rotation of the arm <NUM> by the first rotation mechanism <NUM> and the electromagnetic brake <NUM> is connected to the pulley shaft <NUM>.

As such, since the electromagnetic brake <NUM> is provided in addition to the friction mechanism <NUM>, the rotation of the arm <NUM> is locked by the electromagnetic brake <NUM> to prohibit the rotation of the arm <NUM> as necessary. Further, since the components of the first rotation mechanism <NUM> are connected to the electromagnetic brake <NUM>, the size of each mechanism can be smaller than that in a case in which the first rotation mechanism <NUM> and the electromagnetic brake <NUM> are independently configured.

Next, a radiography apparatus according to a third embodiment of the present disclosure will be described with reference to <FIG>. In addition, the same configurations as those in the second embodiment are denoted by the same reference numerals and the description thereof will not be repeated. The description is focused on the differences between the second and third embodiments.

In the radiography apparatus <NUM> according to the second embodiment, the friction mechanism <NUM> and the electromagnetic brake <NUM> are connected to the pulley shaft <NUM> forming the first rotation mechanism <NUM>. In contrast, as illustrated in <FIG>, in a radiography apparatus <NUM> according to this embodiment, a friction mechanism <NUM> and an electromagnetic brake <NUM> are connected to the support shaft <NUM> forming the second rotation mechanism <NUM>.

As illustrated in <FIG> and <FIG>, each of the friction mechanism <NUM> and the electromagnetic brake <NUM> is provided in the main body <NUM> of the radiography apparatus <NUM>. In the main body <NUM>, a third gear <NUM> is fixed to an outer peripheral surface of the support shaft <NUM> so as to be coaxially rotatable and a fourth gear <NUM> is engaged with the third gear <NUM>.

The friction mechanism <NUM> includes a friction shaft <NUM>, a frictional force generation unit <NUM> that is attached to the friction shaft <NUM> and generates a frictional force, and a clutch <NUM> that switches connection and disconnection between the support shaft <NUM> and the friction shaft <NUM>.

The friction shaft <NUM> is supported by a frame <NUM> of the main body <NUM> through a bearing (not illustrated). Further, the frictional force generation unit <NUM> is attached to one end of the friction shaft <NUM> in the axial direction. In this embodiment, the frictional force generation unit <NUM> is, for example, a rotary damper.

Specifically, the frictional force generation unit <NUM> comprises a rotor (not illustrated) that is fixed to one end of the friction shaft <NUM> in the axial direction, a housing 212A that accommodates the rotor, and a viscous body (not illustrated) that consists of oil filled between the rotor and the housing 212A.

In a case in which the friction shaft <NUM> is rotated, the rotor fixed to the friction shaft <NUM> is rotated in the housing 212A. In this case, a frictional force acts on the outer peripheral surface of the rotor in a direction opposite to the rotation direction due to the viscous resistance of the viscous body filled in the housing 212A. That is, the frictional force acts on the friction shaft <NUM> in the direction opposite to the rotation direction.

The clutch <NUM> is attached to the other end of the friction shaft <NUM> in the axial direction. The clutch <NUM> is, for example, an electromagnetic clutch and has the same configuration as the clutch <NUM> according to the first and second embodiments. That is, the clutch <NUM> comprises a housing <NUM> that is fixed to the fourth gear <NUM> and a shaft fixing portion <NUM> that is fixed to the friction shaft <NUM>.

In a case in which the clutch <NUM> is energized, the housing <NUM> and the shaft fixing portion <NUM> are connected to each other (corresponding to the first state). The frictional force that acts on the friction shaft <NUM> in a direction opposite to the rotation direction acts on the support shaft <NUM> through the fourth gear <NUM> and the third gear <NUM>. Then, in a case in which the arm <NUM> illustrated in <FIG> is rotated about the axis, the frictional force acts on the arm <NUM> in a direction opposite to the rotation direction of the arm <NUM>.

On the other hand, in a case in which the clutch <NUM> is de-energized, the housing <NUM> and the shaft fixing portion <NUM> are disconnected from each other (corresponding to the second state). The frictional force acting on the friction shaft <NUM> does not act on the support shaft <NUM>. Therefore, the frictional force that acts on the arm <NUM> in a case in which the arm <NUM> illustrated in <FIG> is rotated about the axis is less than that in a case in which the clutch <NUM> is energized.

An electromagnetic brake <NUM> is attached to the other end of the support shaft <NUM>. The electromagnetic brake <NUM> has the same configuration as the electromagnetic brake <NUM> according to the second embodiment. That is, the electromagnetic brake <NUM> comprises a housing 204A that is fixed to the main body <NUM> so as not to be rotatable. The support shaft <NUM> is rotatably attached to the housing 204A through a rotor that is provided in the housing 204A.

In a case in which the electromagnetic brake <NUM> is de-energized, a movable iron piece presses the rotor against the inner wall surface of the housing 204A so as to come into close contact therewith. Therefore, the rotation of the rotor with respect to the housing 204A is locked. Then, the rotation of the rotor with respect to the housing 204A is locked to lock the rotation of the support shaft <NUM> fixed to the rotor. The rotation of the support shaft <NUM> is locked to lock the axial rotation of the arm <NUM> illustrated in <FIG> with respect to the bearing <NUM>.

On the other hand, in a case in which the electromagnetic brake <NUM> is energized, a magnetic force is generated in an electromagnet (not illustrated) that is provided in the housing 204A and the movable iron piece (not illustrated) is attracted to the electromagnet. Therefore, 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 be rotated with respect to the housing 204A. That is, the rotation of the rotor is unlocked.

Further, in a case in which the rotation of the rotor is unlocked, the rotation of the support shaft <NUM> is also unlocked. Therefore, the axial rotation of the arm <NUM> illustrated in <FIG> with respect to the bearing <NUM> is unlocked.

As illustrated in <FIG>, a control unit <NUM> controls the energization of the solenoid <NUM> to perform switching between a state in which the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> is permitted and a state in which the attachment and detachment of the image receiving unit <NUM> to and from the arm <NUM> is regulated, as in the second embodiment.

Further, the control unit <NUM> determines whether or not the image receiving unit <NUM> is detached from the arm <NUM> on the basis of a detection signal from the photo sensor <NUM> provided in the image receiving unit <NUM>, as in the second embodiment.

Further, the control unit <NUM> controls the friction mechanism <NUM> provided in the main body <NUM>. That is, the control unit <NUM> transmits a driving signal to the clutch <NUM> of the friction mechanism <NUM> to energize the clutch <NUM>, thereby switching the friction mechanism <NUM> to the first state. The control unit <NUM> de-energizes the clutch <NUM> to switch the friction mechanism <NUM> to the second state.

Further, the control unit <NUM> controls the electromagnetic brake <NUM> provided in the main body <NUM>. That is, the control unit <NUM> transmits a driving signal to the electromagnetic brake <NUM> to energize the electromagnetic brake as in the second embodiment. Then, the rotation of the support shaft <NUM> with respect to the housing 204A of the electromagnetic brake <NUM> illustrated in <FIG> is locked and the rotation of the arm <NUM> with respect to the bearing <NUM> is locked.

The control unit <NUM> de-energizes the electromagnetic brake <NUM> to unlock the rotation of the support shaft <NUM> with respect to the housing 204A illustrated in <FIG>. Then, the axial rotation of the arm <NUM> with respect to the bearing <NUM> is unlocked.

The control flow procedure of the control unit <NUM> according to this embodiment is the same as the control flow procedure of the control unit <NUM> according to the second embodiment. That is, as illustrated in <FIG>, in Step S502, the control unit <NUM> determines whether or not the image receiving unit <NUM> is detached from the arm <NUM>. In a case in which it is determined that the image receiving unit <NUM> is detached from the arm <NUM> (Y in Step S502), the control unit <NUM> switches the friction mechanism <NUM> to the first state. In a case in which it is determined in Step S502 that the image receiving unit <NUM> is attached to the arm <NUM> (N in Step S502), the control unit <NUM> switches the friction mechanism <NUM> to the second state.

The radiography apparatus <NUM> according to this embodiment comprises the second rotation mechanism <NUM> that rotates the arm <NUM> about the axis with respect to the main body <NUM> and the friction mechanism <NUM> that applies a frictional force to the arm <NUM> in a direction opposite to the direction in which the arm <NUM> is rotated by the second rotation mechanism <NUM>. Therefore, similarly to the radiography apparatus <NUM> according to the second embodiment, the friction mechanism <NUM> is switched between the first state and the second state to change a load due to the manual operation force of the arm <NUM>.

Further, according to this embodiment, the friction mechanism <NUM> is connected to the support shaft <NUM> forming the second rotation mechanism <NUM>. As such, in the axial rotation of the arm <NUM>, the components of the second rotation mechanism <NUM> and the components of the friction mechanism <NUM> are operatively associated with each other. Therefore, the size of each mechanism can be smaller than that in a case in which the second rotation mechanism <NUM> and the friction mechanism <NUM> are independently configured.

Further, according to this embodiment, the radiography apparatus further comprises the electromagnetic brake <NUM> that locks the rotation of the arm <NUM> by the second rotation mechanism <NUM>. The electromagnetic brake <NUM> is connected to the support shaft <NUM>.

As such, since the electromagnetic brake <NUM> is provided in addition to the friction mechanism <NUM>, the rotation of the arm <NUM> is locked by the electromagnetic brake <NUM>. Therefore, it is possible to prohibit the rotation of the arm <NUM> as necessary. Further, the components of the second rotation mechanism <NUM> are connected to the electromagnetic brake <NUM>. Therefore, the size of each mechanism can be smaller than that in a case in which the second rotation mechanism <NUM> and the electromagnetic brake <NUM> are independently configured.

Examples of the embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiments and various modifications and changes can be made without departing from the scope and spirit of the present disclosure. Further, the configurations of each of the above-described embodiments can be appropriately combined with each other.

For example, in the first embodiment, the friction mechanism <NUM> is connected to the first rotation mechanism <NUM> that orbitally rotates the arm <NUM>. However, the friction mechanism <NUM> may be connected to the second rotation mechanism <NUM> that rotates the arm <NUM> about the axis. Further, the friction mechanism <NUM> may be connected to each of the first rotation mechanism <NUM> and the second rotation mechanism <NUM>.

Further, in the first to third embodiments, the friction mechanism <NUM> or <NUM> is connected to the first rotation mechanism <NUM> or the second rotation mechanism <NUM>, and the frictional force of the friction mechanism <NUM> or <NUM> is applied to the arm <NUM> through the first rotation mechanism <NUM> or the second rotation mechanism <NUM>. However, the friction mechanism <NUM> or <NUM> may be attached to the arm <NUM> such that the frictional force of the friction mechanism <NUM> or <NUM> is directly applied to the arm <NUM>.

Similarly, in the second and third embodiments, the electromagnetic brake <NUM> or <NUM> is connected to the first rotation mechanism <NUM> or the second rotation mechanism <NUM>, and the first rotation mechanism <NUM> or the second rotation mechanism <NUM> is locked to lock the rotation of the arm <NUM>. However, the electromagnetic brake <NUM> or <NUM> may be attached to the arm <NUM> and the rotation of the arm <NUM> may be directly locked by the electromagnetic brake <NUM> or <NUM>.

In addition, as illustrated in <FIG> and <FIG> as a modification example, in addition to the friction mechanism <NUM> and the electromagnetic brake <NUM>, a pair of operation handles <NUM> may be provided in the connection portion <NUM> of the radiography apparatus <NUM> according to the second embodiment. The pair of operation handles <NUM> are provided independently of the arm <NUM> illustrated in <FIG> and are manually operated to input an operation force for displacing the arm <NUM> to the first rotation mechanism <NUM>.

Specifically, the pair of operation handles <NUM> have the same configuration and comprise a grip portion <NUM> and a handle shaft <NUM> that is fixed to the grip portion <NUM> so as to be coaxially rotatable. The grip portion <NUM> is a portion which the operator grips with hands to operate the operation handle <NUM>. In this modification example, the grip portion <NUM> has a cylindrical shape that has a larger outer diameter than the handle shaft <NUM>.

As illustrated in <FIG>, the handle shaft <NUM> is disposed in parallel to the pulley shaft <NUM> forming the first rotation mechanism <NUM> and is supported by a side wall <NUM> of the connection portion <NUM> through a bearing (not illustrated) so as to be rotatable and movable in the axial direction. The handle shafts <NUM> of the pair of operation handles <NUM> are disposed on the same axis line.

Further, one end of the handle shaft <NUM> of the operation handle <NUM> is exposed from the side wall <NUM> of the connection portion <NUM> to the outside of the connection portion <NUM>. The grip portion <NUM> is provided at the one end of the handle shaft <NUM>. That is, the grip portions <NUM> of the pair of operation handles <NUM> are provided on both side surfaces of the connection portion <NUM> so as to protrude. Therefore, the operator can grip the grip portions <NUM> from both sides of the connection portion <NUM> and operate the operation handle <NUM>.

A switching mechanism <NUM> for switching between a valid state in which the input of an operation force from the operation handle <NUM> to the first rotation mechanism <NUM> is validated and an invalid state in which the input is invalidated is provided at the other end of the handle shaft <NUM> located inside the connection portion <NUM>.

The switching mechanism <NUM> comprises a pair of gears <NUM> that are fixed to the other ends of the pair of handle shafts <NUM> in the axial direction so as to be coaxially rotatable and a biasing member <NUM> that consists of, for example, a coil spring.

The pair of gears <NUM> face each other with a gap therebetween in the axial direction of the handle shaft <NUM>. The first gear <NUM> fixed to the pulley shaft <NUM> is located between the pair of gears <NUM> in the axial direction of the handle shaft <NUM>. In a case in which the gears <NUM> are moved to the other end of the handle shaft <NUM> in the axial direction, the first gear <NUM> is engaged with the gears <NUM>.

The biasing member <NUM> is provided between the pair of gears <NUM>. The gears <NUM> are biased by the biasing member <NUM> in a direction in which they become further away from each other, that is, to one end of the shaft portion in the axial direction. A spacer <NUM> is provided between the gear <NUM> and the side wall <NUM> of the connection portion <NUM>. The spacer <NUM> is a cylindrical member into which the handle shaft <NUM> is inserted. The spacer <NUM> regulates the movement of the gear <NUM> to the side wall <NUM>, that is, the movement of the gear <NUM> to one end of the handle shaft <NUM> in the axial direction.

In a case in which the operation handle <NUM> is operated, the operator grips one of the pair of grips <NUM>, which are provided on both side surfaces of the connection portion <NUM> so as to protrude, with the hand and pushes the grip portion <NUM> to the inside of the connection portion <NUM>, that is, the other end of the handle shaft <NUM> in the axial direction. In this case, the gear <NUM> of the switching mechanism <NUM> fixed to the other end of the handle shaft <NUM> in the axial direction is biased to one end of the handle shaft <NUM> in the axial direction by the biasing member <NUM>. Therefore, the operator pushes the grip portion <NUM> against the biasing force of the biasing member <NUM>.

In a case in which the grip portion <NUM> of one operation handle <NUM> is pushed, the handle shaft <NUM> is moved to the other end in the axial direction, and the gear <NUM> fixed to the other end of the handle shaft <NUM> is also moved to the other end in the axial direction. In this case, since the movement of the gear <NUM> of the other operation handle <NUM> to the one end in the axial direction is regulated by the spacer <NUM>, the gear <NUM> is not moved in the axial direction and one gear <NUM> approaches the other gear <NUM> against the biasing force of the biasing member <NUM>. Therefore, the first gear <NUM> disposed between the gears <NUM> is engaged with the one gear <NUM>.

In a case in which the grip portion <NUM> is rotated with the first gear <NUM> engaged with the one gear <NUM>, the handle shaft <NUM> and the gear <NUM> are rotated with the rotation of the grip portion <NUM> and the first gear <NUM> engaged with the gear <NUM> is rotated. Then, as the first gear <NUM> is rotated, the pulley shaft <NUM> and the pulley <NUM> fixed to the pulley shaft <NUM> are rotated. Since the belt <NUM> fixed to both ends of the arm <NUM> illustrated in <FIG> is wound around the pulley <NUM>, the arm <NUM> is orbitally rotated as the pulley <NUM> is rotated. That is, the operation handle <NUM> can be operated to rotate the arm <NUM>.

In the case of the other operation handle <NUM>, similarly to the one operation handle <NUM>, the grip portion <NUM> of the other operation handle <NUM> is pushed to engage the other gear <NUM> with the first gear <NUM>. The other operation handle <NUM> can be operated to rotate the arm <NUM>.

According to this modification example, the operation handle <NUM> makes it possible to operate the arm <NUM> without directly operating the arm <NUM>. Further, since the arm <NUM> is displaced through the first rotation mechanism <NUM>, the amount of displacement of the arm <NUM> can be adjusted more easily than that in a case in which the arm <NUM> is directly operated.

That is, for example, the gear ratio of the first rotation mechanism <NUM> can be set to adjust the relationship between the amount of rotation of the operation handle <NUM> and the amount of rotation of the arm <NUM>. Therefore, the setting of reducing the amount of rotation of the arm <NUM> with respect to the amount of rotation of the operation handle <NUM> is relatively simple. The operation handle <NUM> makes it easy to finely adjust the amount of rotation of the arm <NUM>.

In many cases, the arm <NUM> holding the irradiation unit <NUM> and the image receiving unit <NUM> is used during surgery. The operation handle <NUM> is provided independently of the arm <NUM>, which makes it possible to separate an operation part operated by the operator from an operation part operated by the assistant. Therefore, the following method can also be used: the assistant rotates the arm <NUM> while avoiding the operation part contaminated by contact with the operator.

In the above-described embodiments, the displacement mechanism for displacing the arm <NUM> is the rotation mechanism (the first rotation mechanism <NUM> and the second rotation mechanism <NUM>) that rotates the arm <NUM>. However, the displacement mechanism for displacing the arm <NUM> is not limited to the rotation mechanism and may be, for example, a slide mechanism <NUM> that slides the arm as illustrated in <FIG>.

Specifically, the slide mechanism <NUM> comprises a rack <NUM> that has one end fixed to the arm <NUM> and a pinion <NUM> that is provided in the main body <NUM>. The rack <NUM> has a plurality of teeth 242A formed on the lower surface and is attached to the main body <NUM> so as to be movable in the horizontal direction (X direction). The pinion <NUM> is a circular gear that has a plurality of teeth 244A formed on the outer peripheral surface and is fixed to the main body <NUM> so as to be rotatable about the axis.

The teeth 244A of the pinion <NUM> are engaged with the teeth 242A of the rack <NUM> such that the rack <NUM> and the pinion <NUM> are operatively associated with each other. Therefore, in a case in which the arm <NUM> is manually slid with respect to the main body <NUM>, the rack <NUM> slides in the direction of an arrow R and the pinion <NUM> engaged with the rack <NUM> is rotated.

In addition, a gear (not illustrated) is engaged with the pinion <NUM>. The friction mechanism <NUM> is connected to the gear. The friction mechanism <NUM> has the same configuration as that in the first embodiment and can be switched between a connected state to the gear and a disconnected state from the gear by the clutch <NUM> (see <FIG>).

In a case in which the clutch <NUM> is energized to connect the gear and the friction mechanism <NUM> (corresponding to the first state), the frictional force of the friction mechanism <NUM> acts on the pinion <NUM>. In a case in which the rack <NUM> is slid to rotate the pinion <NUM>, the frictional force acts on the rack <NUM> in a direction opposite to the movement direction of the rack <NUM>. Therefore, it is possible to apply the frictional force to the arm <NUM>.

In a case in which the clutch <NUM> is de-energized to disconnect the gear from the friction mechanism <NUM> (corresponding to the second state), the frictional force of the friction mechanism <NUM> does not act on the pinion <NUM>. In this case, even in a case in which the rack <NUM> is slid to rotate the pinion <NUM>, the frictional force of the friction mechanism <NUM> does not act on the rack <NUM> and the arm <NUM>. As such, the frictional force of the friction mechanism <NUM> can be applied to the sliding of the arm <NUM>.

Further, in the second embodiment, the image receiving unit <NUM> attached to the arm <NUM> so as to be detachable is a detector that is provided in the housing so as not to be detachable. However, as illustrated as a modification example in <FIG> and <FIG>, an image receiving unit <NUM> that is attached to the arm <NUM> so as to be detachable may include a detector <NUM> and an accommodation portion <NUM>.

Specifically, the detector <NUM> is accommodated in the accommodation portion <NUM> so as to be detachable and the accommodation portion <NUM> is attached to the arm <NUM> so as to be detachable. The detector <NUM> being attachable to and detachable from the accommodation portion <NUM> is synonymous with the detector <NUM> being attachable to and detachable from the arm <NUM>. Therefore, this configuration makes it possible to change the size of the detector <NUM> attached to the arm <NUM>.

Further, the accommodation portion <NUM> can also be attached to and detached from the arm <NUM>. Therefore, in a case in which the size of the detector <NUM> is changed, it is easy to maintain the weight balance of the arm <NUM>. The weights of the irradiation unit <NUM> (see <FIG>) and the image receiving unit <NUM> held at both ends of the C-arm illustrated as an example of the arm <NUM> are balanced to prevent inadvertent orbital rotation and to keep the arm at any rotational position.

Specifically, the center of the orbital rotation of the arm <NUM> (aligned with the axis line M in <FIG>) is aligned with the center of gravity of the entire arm <NUM> including the irradiation unit <NUM> and the image receiving unit <NUM>. Therefore, the arm <NUM> is kept at any rotational position by the effect of the weight balance of the arm <NUM>.

In a case in which the size of the detector <NUM> is changed, the weight of the image receiving unit <NUM> is changed. Therefore, the center of gravity of the arm <NUM> also deviates from the center of the orbital rotation. Therefore, in addition to the detector <NUM>, the accommodation portion <NUM> is attachable to and detachable from the arm <NUM>, which makes it possible to compensate a change in the weight of the detector <NUM> with a change in the weight of the accommodation portion <NUM>. As the accommodation portion <NUM>, for example, a plurality of types of accommodation portions having different weights are prepared in which, for example, a weight adjusting ballast is changed to change the weight. The plurality of types of accommodation portions <NUM> are appropriately used to compensate for a weight change caused by a change in the size of the detector <NUM>.

Therefore, even in a case in which the size of the detector <NUM> is changed, the accommodation portion <NUM> is changed according to the size change to maintain the weight balance between the irradiation unit <NUM> and the image receiving unit <NUM> and to align the center of gravity of the arm <NUM> with the center of the orbital rotation.

Similarly to the detectors according to the first and second embodiments, the detector <NUM> forming the image receiving unit <NUM> consists of, for example, a flat panel detector and receives the radiation which has been emitted from the irradiation unit <NUM> illustrated in <FIG> and transmitted through the subject H with an image receiving surface 248A to detect a radiographic image of the subject H. In this embodiment, the detector <NUM> functions as a portable electronic cassette.

The accommodation portion <NUM> forming the image receiving unit <NUM> is a box with a flat rectangular parallelepiped shape and has a fitting concave portion <NUM> formed in the lower surface and an accommodation concave portion <NUM> that accommodates the detector <NUM>. The fitting concave portion <NUM> has the same configuration as the fitting concave portion <NUM> formed in the lower surface of the image receiving unit <NUM> according to the second embodiment. The fitting convex portion <NUM> provided at the other end of the arm <NUM> is fitted to the fitting concave portion <NUM>. Therefore, the accommodation portion <NUM> is attached to the arm <NUM> so as to be detachable.

Further, similarly to the second embodiment, the arm <NUM> is provided with a solenoid <NUM> that regulates the attachment and detachment of the accommodation portion <NUM> to and from the arm <NUM> and a photo sensor <NUM> as an attachment and detachment detection unit. In this embodiment, the photo sensor <NUM> detects whether or not the accommodation portion <NUM> is detached from the arm <NUM>, that is, whether or not both the accommodation portion <NUM> and the detector <NUM> forming the image receiving unit <NUM> are detached from the arm <NUM>.

As illustrated in <FIG>, an opening 254A for accommodating the detector <NUM> in the accommodation concave portion <NUM> is formed in one of four side surfaces of the accommodation portion <NUM>. In addition, an opening 254B with a square shape which communicates with the accommodation concave portion <NUM> is formed in the upper surface of the accommodation portion <NUM> which faces the irradiation opening 34A (see <FIG>) of the irradiation unit <NUM>.

In a state in which the detector <NUM> is accommodated in the accommodation concave portion <NUM>, an image receiving surface 248A of the detector <NUM> is exposed through an opening 254B that is formed in the upper surface of the accommodation portion <NUM> as illustrated in <FIG>. Therefore, even in a state in which the detector <NUM> is attached to the accommodation portion <NUM>, that is, the arm <NUM>, the radiation emitted from the irradiation unit <NUM> (see <FIG>) can be received by the image receiving surface 248A of the detector <NUM>.

Further, the accommodation portion <NUM> is provided with a photo sensor <NUM> that detects whether or not the detector <NUM> is detached from the accommodation portion <NUM>. The photo sensor <NUM> is provided on a side surface of the accommodation portion <NUM> which is opposite to the side surface in which the opening 254A is formed in the accommodation concave portion <NUM>.

The photo sensor <NUM> has the same configuration as the photo sensor <NUM> and detects a change in the amount of light which has been emitted from a light emitting element and then received by a light receiving element to detect whether or not the detector <NUM> is in the accommodation concave portion <NUM>. The sensor that detects whether or not the detector <NUM> is detached from the accommodation portion <NUM> is not limited to the photo sensor <NUM> and may be, for example, a contact sensor using a piezoelectric element or a microswitch.

In addition to the photo sensor <NUM>, an attachment and detachment regulation mechanism (not illustrated) that fixes the detector <NUM> in the accommodation concave portion <NUM> to prevent the detector <NUM> from falling off and releases the fixation may be provided in the accommodation concave portion <NUM>.

In general, in a state in which the accommodation portion <NUM> is attached to the arm <NUM> and the detector <NUM> is detached from the accommodation portion <NUM>, a change in the weight balance of the arm <NUM> is smaller than that in a state in which both the accommodation portion <NUM> and the detector <NUM> are detached from the arm <NUM>.

Here, in this modification example, for example, the friction mechanism <NUM> is switched to the first state in a case in which the photo sensor <NUM> detects that the accommodation portion <NUM> is attached to the arm <NUM> and the photo sensor <NUM> detects that the detector <NUM> is detached from the accommodation portion <NUM>. That is, the frictional force acting on the arm <NUM> is increased in operative association with the detachment of the detector <NUM> to suppress the inadvertent rotation of the arm <NUM> in a case in which the detector <NUM> is detached.

In addition, the frictional force of the friction mechanism <NUM> may be changed in three steps of a case in which the image receiving unit <NUM> (that is, the detector <NUM> and the accommodation portion <NUM>) is attached to the arm <NUM>, a case in which only the accommodation portion <NUM> is attached to the arm <NUM>, and a case in which the image receiving unit <NUM> is not attached to the arm <NUM>. In this case, it is possible to adjust the frictional force acting on the arm <NUM> according to the magnitude of a change in the weight balance of the arm <NUM>.

Further, in the above-described embodiments, the arm <NUM> can be displaced (rotated) by only a manual operation. However, the arm <NUM> may be rotated by an electric operation, or the manual operation and the electric operation may be switched.

In the above-described embodiments, the first rotation mechanism <NUM> is configured by the track portion 22B and the pulley shaft <NUM> provided in the connection portion <NUM>, the fitting portion 22A formed in the arm <NUM>, and the belt <NUM> fixed to both ends of the arm <NUM>. However, the first rotation mechanism <NUM> may have any configuration as long as it can orbitally rotate the arm <NUM> with respect to the connection portion <NUM> as a support portion.

For example, the first rotation mechanism may be configured by a pinion that is fixed to the rotation shaft (not illustrated) provided in the connection portion <NUM> so as to be coaxially rotatable and a rack (not illustrated) which is provided on the outer peripheral surface of the arm <NUM> and in which a plurality of teeth engaged with the pinion are formed.

In the above-described embodiments, the "second state" of the friction mechanism <NUM> is the state in which the frictional force of the friction shaft <NUM> does not act on the arm <NUM> (the state in which the acting frictional force is <NUM>). However, the "second state" of the friction mechanism <NUM> may be a state in which at least the frictional force acting on the arm <NUM> is less than that in the "first state" and is not limited to the state in which the frictional force is <NUM>. For example, the friction mechanism <NUM> may be switched to the "second state" by adjusting the tightening force of the nut <NUM> illustrated in <FIG> such that the frictional force acting on the friction shaft <NUM> is less than that in the "first state".

In the above-described embodiments, the frictional force in a case in which the friction mechanism <NUM> is in the "first state" is greater than the maximum weight of the image receiving unit <NUM> that can be attached to the arm <NUM>. However, the frictional force in a case in which the friction mechanism <NUM> is in the "first state" may be less than the maximum weight of the image receiving unit <NUM> that can be attached to the arm <NUM>.

In this case, the arm <NUM> is rotated in a case in which the image receiving unit <NUM> is detached from the arm <NUM>. However, in a case in which the difference between the frictional force and the weight is small, it is possible to reduce the rotational momentum. Even in this case, the effect of reducing the rotational momentum of the arm <NUM> is obtained.

In the above-described embodiments, the electromagnetic clutch is used as the clutch <NUM> forming the friction mechanism <NUM>. However, the clutch <NUM> is not limited to the electromagnetic clutch and other known clutches including a powder clutch may be used.

Further, in each of the above-described embodiments, the arm (C-arm) that can be orbitally rotated and can be rotated about the axis has been described as an example of the arm <NUM>. However, an arm (for example, a U-arm having a U-shape in a side view) that can be only rotated about the axis may be used. Similarly to the C-arm, the U-arm can hold, for example, the irradiation unit <NUM> and the image receiving unit <NUM> or <NUM> in a posture in which they face each other.

In addition, X-rays have been described as an example of the radiation. However, the present disclosure is not limited to the X-rays. For example, γ-rays may be used.

In each of the above-described embodiments, for example, the following various processors can be used as a hardware structure of processing units performing various processes, such as the control unit <NUM>. The various processors include, for example, a CPU which is a general-purpose processor executing software to function as various processing units as described above, a programmable logic device (PLD), such as a field programmable gate array (FPGA), which is a processor whose circuit configuration can be changed after manufacture, and a dedicated electric circuit, such as an application-specific integrated circuit (ASIC), which is a processor having a dedicated circuit configuration designed to perform a specific process.

One processing unit may be configured by one of the various processors or a combination of two or more processors of the same type or different types (for example, a combination of a plurality of FPGAs and/or a combination of a CPU and an FPGA). Further, a plurality of processing units may be configured by one processor.

A first example of the configuration in which a plurality of processing units are configured by one processor is an aspect in which one processor is configured by a combination of one or more CPUs and software and functions as a plurality of processing units. A second example of the configuration is an aspect in which a processor that implements the functions of the entire system including a plurality of processing units using one integrated circuit (IC) chip is used. A representative example of this aspect is a system-on-chip (SoC). As such, various processing units are configured by using one or more of the various processors as the hardware structure.

Claim 1:
A radiography apparatus (<NUM>) comprising:
an irradiation unit (<NUM>) that emits radiation;
an arm (<NUM>) that is capable of holding the irradiation unit (<NUM>) and an image receiving unit (<NUM>) that receives the radiation, which has been emitted from the irradiation unit (<NUM>) and transmitted through a subject, in a facing posture;
a support portion that supports the arm;
a displacement mechanism that displaces the arm with respect to the support portion;
a friction mechanism (<NUM>) that is switchable between a first state in which a frictional force is applied to the arm (<NUM>) in a direction opposite to a direction in which the arm is displaced and a second state in which the frictional force applied to the arm is less than the frictional force in the first state;
wherein the displacement mechanism is a rotation mechanism that rotates the arm; characterised in that
the radiography apparatus further comprises an electromagnetic brake (<NUM>) that locks the rotation of the arm (<NUM>) by the rotation mechanism; and that
the rotation mechanism has a rotation shaft (<NUM>) that is rotated with the rotation of the arm (<NUM>), and
the friction mechanism (<NUM>) comprises a friction shaft (<NUM>), a frictional force generation unit (<NUM>) that is attached to the friction shaft (<NUM>) and generates the frictional force, and a clutch (<NUM>) that switches connection and disconnection between the rotation shaft (<NUM>) and the friction shaft (<NUM>) to switch between the first state and the second state.