JP2009233280A - Ascending and descending mechanism, ascending and descending bed, and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an ascending and descending mechanism which is compact and has a large ascending and descending width. <P>SOLUTION: The ascending and descending mechanism has: a base 331, an upper ascending and descending table 332, a telescopic structure 335 which has a lower end connected to the base 331 and an upper end connected to the table 332 and telescoped in the vertical direction; a dog leg-shaped link mechanism part 337 which has a first link 333 and a second link 334 and is configured by turnably coupling one end 333a of the first link 333 to the base 331, turnably coupling one end 334a of the second link 334 to the table 332, and turnably coupling the other end 333b of the first link 333 and the other end 334b of the second link 334; and a turning driving part 336 for turning the first link 333 about one end 333a of the first link 333. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an elevating mechanism, an elevating bed having the elevating mechanism, and an imaging apparatus for imaging a subject using the elevating bed.

  2. Description of the Related Art Conventionally, in various fields, a device that lifts and lowers a table or the like with a lifting mechanism has been used. For example, in X-ray CT imaging, an elevating bed having an elevating mechanism is generally used as a bed for placing a subject.

As an elevating mechanism, for example, there is an elevating mechanism that has a parallel link mechanism and an actuator that expands and contracts in a linear direction, and converts the expansion and contraction motion of the actuator into a rotational motion of the link to realize the lifting operation. It is known (see, for example, Patent Document 1).
JP 2006-231091 A

  Incidentally, as an actuator as described above, an actuator having a cylinder structure is generally known. In the actuator of the cylinder structure, the shortest length is not less than half of the maximum extension due to the structure, and the expansion / contraction width with respect to the maximum extension of the actuator is relatively small. Therefore, in such an elevating mechanism, it is necessary to attach the actuator near the pivot point of the link mechanism and to set the length of the rotating link to a length that ensures a sufficient elevating width.

  However, in the lifting mechanism configured as described above, the length of the link has an effect, and the size (size) of the link mechanism becomes large, and it is difficult to reduce the size.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a small lifting mechanism having a large lifting width, a lifting bed having the lifting mechanism, and an imaging apparatus for imaging a subject using the lifting bed.

  In a first aspect, the present invention provides a base, an upper lifting platform located above the base, a lower end connected to the base, and an upper end connected to the upper lifting platform. A telescopic structure that is stretchable; a first link; and a second link, wherein one end of the first link is rotatably coupled to the base, and one end of the second link is A dogleg-shaped link mechanism, which is pivotably coupled to an upper lifting platform, and wherein the other end of the first link and the other end of the second link are pivotally coupled; There is provided an elevating mechanism provided with a rotation drive unit that rotates one of the link and the second link about one end of the one link.

  In a second aspect, the present invention provides the first aspect, wherein the rotational drive unit includes a motor and a speed reducer that converts the rotational rotational movement of the motor to a reduced speed and transmits it to the one link. A lifting mechanism is provided.

  In a third aspect, according to the present invention, the first link and the second link have the same length, and one end of the first link and one end of the second link are in the vertical direction. The lifting mechanism according to the first aspect or the second aspect substantially overlaps with each other.

  In a fourth aspect, the present invention provides the tubular structure, wherein the stretchable structure has a plurality of tubular members that surround the first link and the second link and have openings on the top and bottom, and are adjacent to each other. An elevating mechanism according to any one of the first to third aspects is provided in which the members slide relative to each other in the vertical direction to expand and contract.

  In a fifth aspect, the present invention is a lifting mechanism according to any one of the first to fourth aspects and a top plate on which a subject is placed, and is lifted and lowered by the lifting mechanism. An elevating bed having a top plate is provided.

  In a sixth aspect, the present invention provides the elevating bed according to the fifth aspect, which supports the top plate so as to be movable in a predetermined horizontal direction and has a top plate support portion that is raised and lowered by the elevating mechanism. .

  In a seventh aspect, the present invention is an auxiliary plate disposed at a predetermined distance from the lifting mechanism in the predetermined direction, and when the top plate moves a predetermined amount or more in the predetermined direction. An auxiliary plate that at least partially overlaps the top plate in the vertical direction, an auxiliary plate elevating mechanism that raises and lowers the auxiliary plate, and the auxiliary plate so that the auxiliary plate contacts the lower surface of the top plate that has moved the predetermined amount or more. The elevating bed according to the sixth aspect, further comprising control means for controlling the plate elevating mechanism.

  In an eighth aspect, the present invention provides the lifting bed according to the seventh aspect, wherein the auxiliary plate lifting mechanism has substantially the same mechanism as the lifting mechanism.

  In a ninth aspect, the present invention provides an image obtained by photographing the lift bed according to any one of the sixth to eighth aspects and the subject placed on the top plate of the lift bed. An imaging apparatus is provided that includes an imaging means for generating information.

  In a tenth aspect, the present invention relates to the elevating bed according to the fifth aspect and the longitudinal direction of the top plate so that the subject placed on the top plate of the elevating bed is placed in the imaging space. And an imaging apparatus including a movable imaging means for imaging the subject and generating image information.

  In an eleventh aspect, in the present invention, the imaging means rotates and projects an X-ray imaging system including an X-ray tube and an X-ray detector facing each other with the subject interposed therebetween. The photographing apparatus according to the ninth aspect or the tenth aspect includes a gantry means for acquiring data.

  According to the present invention, the moving structure of the upper lifting platform is limited in the vertical direction by connecting the telescopic structure that can be stretched in the vertical direction to the base and the upper lifting platform, and the first link and the second link When one of the links pivots around one end, the other pivots around the other end to move the upper lifting platform up and down, so that the length of the pivoting link can be efficiently converted into a lifting width and is compact. Thus, a lifting mechanism having a large lifting width can be realized.

Embodiments according to the present invention will be described below.
(First embodiment)

  First, the overall configuration of the X-ray CT apparatus (imaging apparatus) 1 according to the present embodiment will be described.

  FIG. 1 is an external view of the X-ray CT apparatus 1. As shown in FIG. 1, the apparatus 1 includes a scanning gantry (gantry means) 2, an imaging table (elevating bed) 3, and an operation console 4.

  Here, for ease of explanation, the vertical direction is the y direction, the longitudinal direction of the imaging table 3 is the z direction, and the direction perpendicular to the y direction and the z direction is the x direction.

  The scanning gantry 2 has an X-ray imaging system (not shown) including an X-ray tube and an X-ray detector that are opposed to each other with a cavity 2b that is an imaging space. The scanning gantry 2 rotates the X-ray imaging system around the subject conveyed to the cavity 2b, images the subject, and collects projection data.

  The imaging table 3 carries the subject to the cavity 2b of the scanning gantry 2 by placing the subject on the top and moving the top in the z direction.

  The operation console 4 controls the scanning gantry 2 and the imaging table 3 based on the input information of the operator, obtains projection data from the scanning gantry 2, and generates a tomographic image of the subject.

  FIG. 2 is a block diagram showing the overall configuration of the X-ray CT apparatus 1. The scanning gantry 2 includes an X-ray tube 21, a collimator 22 and an X-ray detector 23, and constitutes an X-ray irradiation / detection device. The X-rays radiated from the X-ray tube 21 are shaped by the collimator 22 into, for example, a fan-shaped X-ray beam, that is, a fan beam X-ray, and irradiated to the X-ray detector 23.

  The X-ray detector 23 has a plurality of X-ray detection elements arranged in an array in the spreading direction of the fan beam X-rays. The X-ray detector 23 is a multi-channel X-ray detector in which a plurality of X-ray detection elements are arranged in an array.

  A data collection unit 24 is connected to the X-ray detector 23. The data collection unit 24 collects detection data of individual X-ray detection elements constituting the detector array. X-ray irradiation from the X-ray tube 21 is controlled by an X-ray controller 25 in the scanning gantry 2.

  The above-described components from the X-ray tube 21 to the X-ray controller 25 are mounted on the rotating unit 26 of the scanning gantry 2. Here, the subject is placed in a recumbent state on the top plate 31 in the hollow portion 2 b located at the center of the rotating portion 26. The rotating unit 26 rotates while being controlled by the rotation controller 25, exposes X-rays from the X-ray tube 21, and detects X-rays of the subject in the X-ray detector 23.

  The operation console 4 includes a console control unit 41, a data collection buffer 42, an input / output unit 43, a storage unit 44, and the like. A data collection buffer 42 is connected to the console control unit 41, and the data collection buffer 42 is further connected to the data collection unit 24 of the scanning gantry 2. Here, the data collected by the data collection unit 24 is input to the console control unit 41 through the data collection buffer 42.

  The console control unit 41 performs image reconstruction using a transmission X-ray signal collected through the data collection buffer 42, that is, projection data. A storage unit 44 is also connected to the console control unit 41. The storage unit 44 stores projection data collected in the data collection buffer 42, reconstructed tomographic image information, a program for realizing the functions of the apparatus, and the like.

  An input / output unit 43 is connected to the console control unit 41. The input / output unit 43 includes a display device and an operation device, and displays tomographic image information and other information output from the console control unit 41. The input / output unit 43 is operated by an operator and inputs various instructions, information, and the like from the operation device to the control unit 41. An operator operates the apparatus interactively using a display device.

  Moreover, the imaging table 3 is connected to the console control part 41, and the height control of the imaging table 3, the position control of a top plate, etc. are performed. Thereby, the subject on the top is placed at the optimum image acquisition position.

  Here, the configuration of the imaging table 3 will be described in detail.

  FIG. 3 is a diagram illustrating the configuration of the imaging table 3. FIG. 3A is a side view of the main part of the imaging table 3 viewed in the x direction, and FIG. It is a rear view when the principal part is seen in the z direction.

  As shown in FIG. 3, the imaging table 3 includes a top board 31, a top board support part 32, and an elevating mechanism part 33.

  The top plate 31 has a placement surface on which the subject is placed.

  As shown in FIG. 3A, the top plate support part 32 supports the top plate 31 so as to be movable in the z direction. Specifically, for example, the top plate support section 32 has a roller (not shown) that supports the top plate 31 and a motor that drives the roller to rotate. The plate 31 is moved out in the z direction. The top board support part 32 is raised and lowered by the raising / lowering mechanism part 33, and the top board 31 is also raised and lowered at the same time. The top plate 31 has a home position (home position), and moves to the cavity 2b by moving in the z direction from this home position.

  The elevating mechanism unit 33 elevates and lowers the top plate support unit 32. As shown in FIGS. 3 and 4, the elevating mechanism unit 33 includes a base 331, an upper elevating table 332, an elastic structure 335, a dogleg-shaped link mechanism unit 337, and a rotation driving unit 336.

  The base 331 is a base installed on the floor surface. Here, the base 331 has a rectangular parallelepiped shape.

  The upper lifting platform 332 is located above the base 331 and supports the top plate support part 32. The upper lifting platform 332 is, for example, a plate-shaped member or structure, or a frame-shaped structure formed of a plurality of columnar members or cylindrical members extending in the horizontal direction. Here, the upper lifting platform 332 has a substantially rectangular parallelepiped shape and has a bracket 3321 that protrudes downward.

  The dogleg-shaped link mechanism 337 includes a first link 333 and a second link 334. One end 333 a of the first link 333 is rotatably coupled to the base 331 via a rotation driving unit 336. One end 334a of the second link 334 is coupled to the bracket 3321 of the upper lifting platform 332 by a coupling portion 339 so as to be rotatable. Further, the other end 333 b of the first link 333 and the other end 334 b of the second link 334 are coupled to each other by a coupling portion 338.

  The first link 333 and the second link 334 have the same length, and the one end 333a of the first link 333 and the one end 334a of the second link 334 substantially overlap each other in the vertical direction. That is, the first link 333 and the second link 334 are vertically symmetric with respect to the horizontal axis passing through the coupling portion 338. With such a configuration, the length of the link can be most efficiently converted into the lift width.

  The telescopic structure 335 is a structure that can be vertically expanded and contracted, with a lower end connected to the base 331 and an upper end connected to the upper lifting platform 332. The telescopic structure 335 expands and contracts only in the vertical direction while keeping the base 331 and the upper lifting platform 332 in parallel. Here, as shown in FIG. 3A, the stretchable structure 335 has a plurality of cylindrical members 3351 that surround the first link 333 and the second link 334 and have openings in the upper and lower directions in the inner and outer directions. . One of the innermost cylindrical member and the outermost cylindrical member has a lower end connected to the base 331, and the other cylindrical member has an upper end connected to the upper lifting platform 332. . Adjacent cylindrical members are coupled by a linear guide 3352 so as to be relatively slidable in the vertical direction. The mounting location and number of the linear guides 3352 are not particularly limited, but the linear guide 3352 is installed in consideration of sliding in the vertical direction while maintaining sufficient rigidity. Accordingly, the telescopic structure 335 expands and contracts telescopically only in the vertical direction. With this configuration, the doglegged link mechanism 337 can be protected from the outside. In the present embodiment, the number of cylindrical members is 3, but the present invention is not limited to this.

  The rotation drive unit 336 rotates the first link 333 around its one end 333a. Here, the rotation drive unit 336 includes a motor and a speed reducer that converts the rotational rotational motion of the output shaft of the motor to the first link 333 by decelerating and converting it. Specifically, a motor with a speed reducer in which the motor and the speed reducer are integrated is fixed to the base 331, and the output shaft of the motor with the speed reducer is fixed to one end 333a of the first link 333. . When this output shaft is rotated, the first link 333 rotates around the output shaft. Note that various kinds of reduction gears can be considered, for example, one constituted by a plurality of gears and one constituted by a gear and a belt engaged with the gears.

  Next, the operation of the imaging table 3 will be described.

  FIG. 4 is a diagram illustrating the operation of the dogleg-shaped link mechanism 337 configured by the first link 333 and the second link 334.

  The first link 333 receives a force that rotates about the one end 333 a by the drive of the rotation driving unit 336. Thereby, the coupling part 338 of the first link 333 moves in the vertical direction while performing a circular motion around the one end 333a.

  On the other hand, since the telescopic structure 335 can be expanded and contracted only in the vertical direction, the upper lifting platform 332 can be moved only in the vertical direction, and the coupling portion 339 of the second link 334 can also be moved only in the vertical direction.

  For this reason, the coupling part 339 is also moved in the vertical direction by the vertical movement accompanying the circular motion of the coupling part 338. That is, when the coupling part 338 moves upward, the coupling part 339 also moves upward, the upper lifting platform 332 rises, and the top board support part 32 and the top board 31 rise. On the contrary, when the coupling part 338 moves downward, the coupling part 339 also moves downward, the upper lifting platform 332 descends, and the top board support part 32 and the top board 31 descend.

  According to the present embodiment as described above, the movable structure 335 that can be expanded and contracted in the vertical direction is connected to the base 331 and the upper lifting platform 332, thereby restricting the moving direction of the upper lifting platform 332 in the vertical direction. When the first link 333 rotates around its one end, the second link 334 also rotates around its one end and moves the upper lifting platform 332 up and down. For example, due to the deformation of the pantograph Ascending / descending operation is performed only on one side half with respect to the left / right symmetry axis, and the length of the rotating link can be efficiently converted to the ascending / descending width, so that the ascending / descending mechanism portion having a small and large ascent / descent width can be realized. In addition, it is possible to realize a small-sized lift bed with a large lift width and an imaging device for photographing a subject using the lift bed.

Note that a type of lifting mechanism that can be downsized by supporting the top plate from the side in a horizontal direction and moving the supporting part up and down is also conceivable. This is a type in which an elevating mechanism is provided under the plate, and there is no portion protruding higher than the placement surface on which the subject of the top plate 31 is placed unlike the previous type. Therefore, according to the present embodiment, when the subject conveyed by the stretcher is moved from the front-rear direction of the imaging table to the top plate, there is no obstacle and the subject is smooth. Can be moved.
(Second Embodiment)

  An X-ray CT apparatus 1s according to a second embodiment of the present invention will be described.

  FIG. 5 is a diagram showing a configuration of an X-ray CT apparatus 1s according to the second embodiment. As shown in FIG. 5, the X-ray CT apparatus 1 s includes a scanning gantry 2, an imaging table 3, an operation console 4, an auxiliary table 5, and an elevation control unit 6. This is a configuration in which an auxiliary table 5 and an elevation control unit 6 are further provided in the scanning gantry 2, the imaging table 3, and the operation console 4 in the first embodiment. Therefore, detailed description of the scanning gantry 2, the imaging table 3, and the operation console 4 is omitted.

  The auxiliary table 5 is arranged so that the scanning gantry 2 is sandwiched between the auxiliary table 5 and the top table 31 that has moved through the cavity 2b of the scanning gantry 2 to support the top table 31. The deflection of the plate 31 is reduced.

  The auxiliary table 5 has an auxiliary plate 52 and an auxiliary plate lifting mechanism 53.

  The auxiliary plate 52 is arranged at a predetermined distance in the z direction from the lifting mechanism 33 of the imaging table 3, and at least a part of the auxiliary plate 52 has a certain amount S of the top plate 31 in the z direction from the home position. When moved above, the top plate 31 is arranged so as to overlap in the vertical direction.

  The auxiliary plate elevating mechanism 53 raises and lowers the auxiliary plate 52. The auxiliary plate lifting mechanism 53 has substantially the same mechanism as the lifting mechanism 33. That is, as shown in FIG. 5, the auxiliary plate lifting mechanism 53 has a base 531, an upper lifting platform 532, a first link 533, a second link 534, a telescopic structure 535, and a rotation driving unit 536. These correspond to the components 331 to 336 in the imaging table 3, respectively.

  The elevating control unit 6 sets the elevating state of the auxiliary plate elevating mechanism unit 53 so that the auxiliary plate 52 contacts the lower surface of the top plate 31 when the top plate 31 moves from the home position by a certain amount S in the z direction. Control. When the elevation mechanism unit 33 is controlled and the height position of the top plate 31 changes, the elevation control unit 6 controls the auxiliary plate elevation mechanism unit 53 so that the height position of the auxiliary plate 52 changes accordingly. Control. The fixed amount S corresponds to the distance in the z direction from the tip of the top plate 31 stopped at the home position to the edge of the auxiliary plate 52 on the imaging table 3 side. For example, the elevating control unit 6 acquires information for specifying the height position of the top plate 31 in the imaging table 3 from the operation console 4 or the imaging table 3 and rotates the auxiliary plate elevating mechanism unit 53 based on the information. The drive unit 536 is controlled. In consideration of the bending of the top plate 31 to some extent, the lifting control unit 6 raises and lowers the auxiliary plate 52 so that the height position of the auxiliary plate 52 is lower than that of an ideal top plate without deflection. The mechanism unit 53 is controlled.

  According to the second embodiment as described above, when the top plate 31 moves greatly, the auxiliary table 5 supports the tip portion of the top plate 31 in particular. The deflection of the top plate 31 can be reduced. Thereby, the deviation | shift amount from the ideal of an imaging position can be made small.

Further, according to the second embodiment, since the lifting mechanism 33 and the auxiliary plate lifting mechanism 53 have substantially the same mechanism, the photographing table 3 and the auxiliary table 5 share the lifting mechanism. Can be Thereby, the control method of the raising / lowering mechanism part 33 and the auxiliary | assistant board raising / lowering mechanism part 53 can also be made common, control can be simplified, and cost (cost) can also be reduced. In addition, since the lifting mechanism is small, the space occupied by the auxiliary table 5 can be reduced, and a practical imaging table having a dual-support structure can be realized.
(Third embodiment)

  An X-ray CT apparatus 1t according to a third embodiment of the present invention will be described.

  FIG. 6 is a diagram showing a configuration of an X-ray CT apparatus 1t according to the third embodiment. As shown in FIG. 6, the X-ray CT apparatus 1 t includes a scanning gantry 2 t, an imaging table 3, and an operation console 4. This is a configuration in which the scanning gantry 2 is changed to the scanning gantry 2t in the scanning gantry 2, the imaging table 3, and the operation console 4 in the first embodiment. Therefore, detailed description of the imaging table 3 and the operation console 4 is omitted.

  The scanning gantry 2t moves in the longitudinal direction of the top plate 31, that is, in the z direction so that the subject placed on the top plate 31 of the imaging table 3 is arranged in the cavity 2b that is the imaging space. This is a movable X-ray CT gantry that images a specimen and generates image information.

  In such an X-ray CT apparatus 1t, the scanable range of the top 31 is determined by the movable range in the z direction of the scanning gantry 2t, and the movable range of the scanning gantry 2t is the lifting mechanism 33 of the imaging table 3. Limited by position. Therefore, in order to widen the scannable range, it is advantageous that the lifting mechanism 33 is small.

  In addition, according to the present embodiment, since the lifting mechanism 33 can be reduced in size as compared with a conventional lifting mechanism that combines a link mechanism and an actuator, scanning is possible in an X-ray CT apparatus that uses a movable gantry. A wider range can be taken.

  The present invention is not limited to the above-described embodiments, and various embodiments and modifications thereof can be considered without departing from the spirit of the present invention.

  For example, the elevating mechanism according to the present invention is not limited to the elevating mechanism of the bed, and can be applied to all elevating mechanisms that are small and require a large elevating width.

  In addition, the lift bed according to the present invention is not limited to the imaging table, and can be applied to uses other than shooting, for example, an elevator table for the purpose of treatment or surgery.

  In addition, the imaging apparatus according to the present invention is not limited to the X-ray CT apparatus, and can be applied to all imaging apparatuses in which adjustment work for placing the subject on the top and moving up and down is performed. .

  Further, the elastic structure 333 in the first to third embodiments and the elastic structure 533 in the second embodiment described above are combined with a plurality of frames instead of the cylindrical member. You may make it use the structure which becomes.

  Moreover, in said 1st Embodiment to 3rd Embodiment, the upper raising / lowering stand 332 and the top-plate support part 32 may be integrally formed.

  In the first to third embodiments, the first link 333 and the second link 334 may have different lengths.

  In the first to third embodiments, one end 333 a of the first link 333 is rotatably coupled to the base 331, and one end 334 a of the second link 334 is connected to the upper lifting platform 332. It may couple | bond so that rotation is possible, and you may provide the rotation drive part 336 in the upper raising / lowering stand 332 side so that the 2nd link 334 may be rotated centering on the end 334a.

  In the first to third embodiments, when the rotation drive unit 336 is a motor with a speed reducer, the output shaft of the motor with a speed reducer and the rotation center of the link to be rotated For example, a configuration may be adopted in which a rotating gear is fixed to one end of a link to be rotated, and the shaft rotational motion of the motor with a speed reducer is transmitted to the rotating gear using a belt or a gear. .

  In the third embodiment, the top plate 31 of the imaging table 3 may not be movable in the z direction.

1 is an external view of an X-ray CT apparatus according to a first embodiment. 1 is a block diagram showing an overall configuration of an X-ray CT apparatus according to a first embodiment. It is a figure which shows the structure of the principal part of the imaging | photography table by 1st Embodiment. It is a figure for demonstrating operation | movement of the raising / lowering mechanism of the imaging table by 1st Embodiment. It is a figure which shows the structure of the X-ray CT apparatus by 2nd Embodiment. It is a figure which shows the structure of the X-ray CT apparatus by 3rd Embodiment.

Explanation of symbols

1, 1s, 1t X-ray CT system (imaging system)
2, 2t scanning gantry (gantry means)
2b Cavity 3 Shooting table (lifting bed)
4 Operation console 5 Auxiliary table 6 Elevating control unit 21 X-ray tube 22 Collimator 23 X-ray detector 24 Data collecting unit 25 X-ray controller 26 Rotating unit 27 Rotating controller 31 Top plate (top plate)
32 Top plate support (top plate support)
33 Elevating mechanism (elevating mechanism)
41 Console Control Unit 42 Data Collection Buffer 43 Input / Output Unit 44 Storage Unit 52 Auxiliary Plate 53 Auxiliary Plate Elevating Unit 331 Base (Base)
332 Upper elevator (upper elevator)
333 First link 334 Second link 335 Stretchable structure (stretchable structure)
336 Rotation Drive Unit (Rotation Drive Unit)
337 U-shaped link mechanism (link mechanism)
338, 339 Connecting portion 3321 Bracket 3351 Tubular member 3352 Linear guide

Claims (11)

Base and
An upper lifting platform located above the base;
A lower end is connected to the base, and an upper end is connected to the upper lifting platform, respectively, and an elastic structure that can expand and contract in the vertical direction;
A first link and a second link, wherein one end of the first link is rotatably coupled to the base, and one end of the second link is pivotally coupled to the upper lifting platform A dog-shaped link mechanism formed by rotatably connecting the other end of the first link and the other end of the second link;
An elevating mechanism comprising: a rotation drive unit that rotates one of the first link and the second link about one end of the one link.   2. The lifting mechanism according to claim 1, wherein the rotation driving unit includes a motor and a speed reducer that transmits the rotational rotational motion of the motor to the one link by decelerating. The first link and the second link have equal lengths to each other;
The elevating mechanism according to claim 1 or 2, wherein one end of the first link and one end of the second link substantially overlap each other in the vertical direction.   The elastic structure includes a plurality of cylindrical members having openings in the vertical direction surrounding the link mechanism, and the adjacent cylindrical members slide relative to each other in the vertical direction to expand and contract. The raising / lowering mechanism of any one of Claim 3.   An elevating bed comprising: the elevating mechanism according to any one of claims 1 to 4; and a top plate on which a subject is placed and is raised and lowered by the elevating mechanism.   The elevating bed according to claim 5, further comprising a top plate supporting portion that supports the top plate so as to be movable in a predetermined horizontal direction and is raised and lowered by the elevating mechanism. An auxiliary plate disposed at a predetermined distance in the predetermined direction from the lifting mechanism, and at least a part of the auxiliary plate is moved up and down with respect to the top plate when the top plate moves in a predetermined amount or more in the predetermined direction. Auxiliary plates that overlap in the direction,
An auxiliary plate lifting mechanism for raising and lowering the auxiliary plate;
The elevating bed according to claim 6, further comprising control means for controlling the auxiliary plate elevating mechanism so that the auxiliary plate abuts the lower surface of the top plate moved by the predetermined amount or more.   The elevating bed according to claim 7, wherein the auxiliary plate elevating mechanism has substantially the same mechanism as the elevating mechanism.   An imaging apparatus comprising: the elevating bed according to any one of claims 6 to 8; and imaging means for imaging the subject placed on the top plate of the elevating bed and generating image information.   The lift bed according to claim 5 and the subject placed on the top plate of the lift bed are moved in the longitudinal direction of the top plate so as to be arranged in the imaging space, and the subject is photographed and imaged An imaging apparatus comprising movable imaging means for generating information.   The imaging means includes gantry means for acquiring projection data by rotating an X-ray imaging system including an X-ray tube and an X-ray detector facing each other with the subject interposed therebetween. The imaging device according to claim 9 or claim 10.

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