Rotating patient table for RT applications

Abstract

A patient couch has a base (1) and a superstructure (2) connected to each other by a lifting mechanism (3). A table (4) is arranged on the superstructure (2), on which an adult person can be positioned. The base (1) is supported at one end (1', 1") by means of a swivel bearing (5) on a surface (6) and is thus rotatable about a vertical axis of rotation (7). The other end (1") of the base (1) is not supported. The lifting mechanism (3) is arranged between the two ends (1', 1") of the base (1) and beneath the superstructure (2). A drive (8) is arranged on the base (1) and acts on a drive shaft (10) of a gearbox (11). Rotation of the drive shaft (10) causes rotation of an output shaft (12). The gearbox (11) has a gearbox housing (13) that is fixed to the base (6) and in which the drive shaft (10) and the output shaft (12) are mounted.A boom (15) is fixedly mounted on the output shaft (12) and connected to the base (1). When the output shaft (12) rotates, the boom (15) exerts a torque on the base (1), causing the base (1) to rotate about the axis of rotation (7). The gearbox (11) is a separate component from the rotary bearing (5). The gearbox housing (13) is located radially within the rotary bearing (5) and axially in the area of ​​the rotary bearing (5), relative to the axis of rotation (7). The boom (15) acts on the base (1) via a coupling element (16). This coupling element transmits the torque exerted on the boom (15) to the base (1) while allowing radial movement of the boom (15) relative to the base (1).

Description

[0001] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0002] The present invention relates to a patient bed, - wherein the patient bed has a base and a superstructure which are connected to each other via a lifting mechanism, - wherein a reclining table is arranged on the upper structure, on which an adult person can be reclined, - wherein the substructure is supported at one of its ends on a base by means of a swivel bearing, so that the substructure can be rotated about a vertical axis of rotation, - where the other end of the substructure is not supported, - wherein the lifting mechanism is arranged between one and the other end of the substructure and under the superstructure, - wherein a drive is arranged on the substructure which acts on a drive shaft of a gearbox, - wherein a rotation of the drive shaft causes a rotation of an output shaft, - wherein the gearbox has a gearbox housing which is fixed to the base in such a way as to prevent rotation and in which the input shaft and the output shaft are mounted, - wherein a boom is arranged on the output shaft in a rotationally fixed manner and is connected to the base, so that when the drive shaft is rotated, the boom exerts a torque on the base, causing the base to rotate about the axis of rotation.

[0003] This type of patient bed is generally known.

[0004] When using a patient table for radiotherapy applications (a so-called RT couch), it is necessary to be able to position the tabletop and the radiation generator relative to each other precisely, yet as freely as possible. In some cases, the patient table is designed as described above. The base is sometimes fixed relative to the space in which the radiation generator is located. In other cases, it is a rotating platform. In this case, the pivot bearing is usually located as close as possible to the edge of the platform.

[0005] Due to the placement of the pivot bearing at the end of the base, a high tilting moment can act upon it. This tilting moment must be absorbed and counteracted by the pivot bearing. Suitable pivot bearings are known. In practice, however, the additional problem arises that the available installation space—especially the installation height—must be kept very small to ensure sufficient freedom of movement for the rotating RT gantry. Furthermore, it is necessary to be able to rotate the base (and all components mounted on it) very precisely around the axis of rotation. Additionally, a cable routing must be provided in the area of ​​the pivot bearing, alongside the mechanical components.

[0006] In the current state of the art, so-called compact gearboxes with integrated bearings are used for mechanical axes with similar requirements (high torque due to an asymmetrical load application, high precision, and severely limited installation space). An example of such a gearbox is a cycloidal gearbox. Here, ready-made gearbox units are available that can be adapted to machine interfaces as standardized components. This component incorporates both the bearings and the gearbox. In this case, the size of the component is determined by the tilting moment that it must absorb and counteract.

[0007] In the case of a patient bed, a patient mass of 300 kg is typically assumed, sometimes even slightly more. Due to the patient's eccentric positioning relative to the axis of rotation on the bed and the relatively high weight of the bed itself, the tipping moment is very large. Correspondingly, the aforementioned component must also be designed to be correspondingly large. However, this conflicts with the free movement of the radiation generator.

[0008] The prior art includes, among others, German patent application DE 603 ​​03 641 T2, which describes an integrated system with a CT scanner and a radiation therapy device, using a dual-function bed for linear movement and optional isocentric rotation. German patent application DE 102 21 180 A1 discloses a patient positioning device with a vertical isocentric axis and continuously adjustable leveling for precise alignment at the isocenter. US patent 2024 / 0 157 175 A1 shows a medical device with a ring gantry and a rotatable patient table that allows rotation about a vertical axis via compact guide elements to correct positional errors and achieve variable beam angles. The object of the present invention is to create a patient table in which the size of the device, which includes both the rotary bearing and the gearbox, can be kept as small as possible.

[0009] The problem is solved by a patient couch with the features of claim 1. Advantageous embodiments of the patient couch are the subject of dependent claims 2 to 12.

[0010] According to the invention, a patient bed of the type mentioned above is designed by: - that the gearbox is a component different from the rotary bearing, - that the gearbox housing, with respect to the axis of rotation, is arranged radially within the rotary bearing and axially in the area of ​​the rotary bearing and - that the boom acts on the substructure via a coupling element, by means of which the torque exerted on the boom is transferred to the substructure, but a radial movement of the boom relative to the substructure is still allowed.

[0011] The invention is based, on the one hand, on the idea of ​​separating the two required functionalities – namely, the rotatable bearing and the application of the torque required for rotation while simultaneously precisely adjusting the angle of rotation. Since the torque is relatively low, the gearbox can be designed to be small. In particular, this separation makes it possible to arrange the gearbox housing radially within the rotary bearing and axially in the area of ​​the rotary bearing. The type of gearbox can be chosen according to requirements. It could, for example, be a cycloidal gearbox, a so-called wave gearbox, a planetary gearbox, or another type of axial gearbox.

[0012] However, implementing the system in two separate components would necessitate highly precise alignment of the gearbox housing relative to the rotary bearing if the boom were rigidly connected to the base. Specifically, the axis of rotation of the output shaft would have to be exactly coaxial with the axis of rotation of the rotary bearing. Such high-precision alignment is difficult to achieve in practice. However, the coupling element, which acts as a torque support and allows radial movement of the boom relative to the base, eliminates the need for this high-precision alignment. The slight offset of the output shaft's axis of rotation relative to the rotary bearing's axis of rotation—typically 1 mm or less in practice—can easily be compensated for by a corresponding (small) radial movement of the boom. Therefore, the present invention makes it possible to easily accommodate a small offset.Nevertheless, the gearbox exhibits a constant rotational resistance across its entire rotational range. At the same time, the precision requirements for the assembly interfaces can be kept low.

[0013] When the base is rotated, not only the base itself is rotated. Rather, the lifting mechanism and the upper structure also rotate relative to the floor around the vertical axis of rotation. Furthermore, the reclining table can be moved (at least) in its longitudinal direction. In this case, depending on the direction of travel, the tilting moment acting on the pivot bearing can be significantly increased or decreased. The pivot bearing must, of course, be designed to withstand the most unfavorable assumed scenario.

[0014] Several solutions are possible for the design of the coupling element. One simple solution is to design the coupling element as an elongated slot with a radially extending longitudinal axis. In this case, a pin of the boom is inserted into the elongated slot. Conversely, it is also possible to design the coupling element as a pin. In this case, the pin is inserted into an elongated slot in the boom with a radially extending longitudinal axis. In both cases, the pin extends axially with respect to the axis of rotation. Another solution is to design the coupling element as a lever with two ends, extending essentially tangentially to the axis of rotation. In this case, one end of the lever is pivotally connected to the base and the other to the boom.

[0015] Other solutions are also possible. For example, the coupling element can also be designed as an elastic tension / compression element, such as a sheet metal strip. A backlash-free fastening of such a sheet metal strip to the boom and the substructure results in a simple, backlash-free, and rigid transmission of torque.

[0016] The rotary bearing has an inner diameter. Likewise, the gearbox housing has a housing diameter. However, the housing diameter of the gearbox is smaller than the inner diameter of the rotary bearing. This creates an annular gap between the rotary bearing and the gearbox housing. In a preferred embodiment, a feedthrough is arranged in this annular gap through which a cable is routed from the ground into the substructure. The drive is supplied with electrical energy via this cable. Optionally, data (e.g., actual position or current values) can also be transmitted from the drive back to a control unit via this cable.

[0017] The base is typically rotatable between two end positions by means of the drive mechanism. Preferably, when the base is in a middle rotational position between the two end positions, the gearbox housing is arranged between the other end of the base and the bushing. This design has proven to be particularly reliable for the cable in continuous operation.

[0018] Preferably, the drive is arranged between the other end of the base and the rotary bearing. This is advantageous for design reasons and especially with regard to the resulting overall height.

[0019] The rotary bearing typically has an outer diameter. In this case, the distance of the drive from the axis of rotation is preferably larger than the outer diameter.

[0020] In one possible embodiment, the cable is designed as a drag chain, which is either placed in or removed from the annular gap depending on the direction in which the base is rotated by the drive. This design operates reliably and is particularly space-saving. In particular, no additional installation space is required above the gearbox and the rotary bearing to accommodate the cable.

[0021] Preferably, the cable remains enclosed in a protective sheath. In this case, the protective sheath is placed in or removed from the annular gap along with the cable. The cable thus remains permanently within the protective sheath.

[0022] In another embodiment, a first end section of the cable is fixed to the substructure, and a second end section is located in the area of ​​the cable entry. In this case, a cable drum is mounted on the substructure, allowing the drum to be moved translationally and rotated about its axis. A section of the cable located between the first and second end sections is fixed inside the drum. As the drum rotates around its axis, the cable either unwinds or winds towards both the first and second end sections, depending on the direction of rotation. This embodiment has the advantage that the cable drum limits the cable's bending radii, which change dynamically during winding and unwinding, to small radii. While very small bending radii can occur within the drum section itself, these radii are static.Therefore, only a single bending occurs here, not a re-bending with each winding and unwinding. The drum axis can be oriented as required. It is often oriented either vertically or horizontally, with the former being preferred. The cable drum assembly can be very compact. Furthermore, the cable drum can be pre-assembled as a separate unit. The cable is only subjected to tensile stress; no torsion occurs.

[0023] A first contact area of ​​the cable drum is defined by the fact that, at this point, a first section of the cable wound onto the drum transitions into a section of the cable extending towards the first end section. Similarly, a second contact area of ​​the cable drum is defined by the fact that, at this point, a second section of the cable wound onto the drum transitions into a section of the cable extending towards the second end section. Preferably, the first and second contact areas of the cable drum are located approximately diametrically opposite each other with respect to the drum axis. This allows the cable drum to discharge the cable towards both the first and second end sections with at least substantially the correct orientation.

[0024] Preferably, the cable drum has a first collecting area and a second collecting area. The first collecting area serves to wind up the section of cable extending from the drum section to the first end section, and the second collecting area serves to wind up the section of cable extending from the drum section to the second end section. In this case, the collecting areas are offset from each other when viewed in the direction of the drum axis, i.e., they are arranged one above the other.

[0025] Preferably, the cable remains enclosed in a protective sheath. In this case, the protective sheath is wound or unwound together with the cable. The cable therefore remains permanently within the protective sheath.

[0026] The properties, features, and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more readily understandable in connection with the following description of the exemplary embodiments, which are explained in more detail in conjunction with the drawings. These drawings show, in schematic representation: Fig. 1 a patient bed, Fig. 2. A perspective view of part of a substructure, a patient bed, and part of a surface. Fig. 3 a section through a substructure and a substrate and components of the patient bed arranged there, Fig. 4 A side view of a boom and a coupling element, Fig. 5 a cut along a line VV in Fig. 4, Fig. 6 a top view of a substructure, Fig. 7 a top view of a substructure, Fig. 8 and Fig. 9 top views analogous to Fig. 7 in other rotational positions of the base and Fig. 10 a cable drum and sections of cable.

[0027] According to Fig. Figure 1 shows a patient couch for RT applications comprising a base 1 and a superstructure 2. The base 1 and the superstructure 2 are connected to each other via a lifting mechanism 3. The lifting mechanism 3 can, for example, be designed as a scissor lift. However, other configurations are also possible, such as a hydraulic or pneumatic cylinder, or a screw inserted into a threaded bore that can be unscrewed by a motor. The lifting mechanism 3 is located beneath the superstructure 2.

[0028] A reclining table 4 is arranged on the superstructure 2. The reclining table 4 is dimensioned such that an adult person (not shown) can lie on it. The reclining table 4 therefore has a length of approximately 2 m or slightly more and a width of approximately 60 cm. The reclining table 4 can be arranged on the superstructure 2 in such a way that it is movable in its longitudinal direction and possibly also in its transverse direction.

[0029] The substructure 1 extends from one end 1' to the other end 1". The lifting mechanism 3 is arranged between one and the other end 1', 1" of the substructure 1. At one end 1', the substructure 1 is - see also the Fig. 2 and Fig. 3 - supported on a base 6 by means of a swivel bearing 5. The base 1 is thus rotatable about a vertical axis of rotation 7. The other end 1" is not supported. The base 6 itself is rotatable about another vertical axis of rotation.

[0030] The rotation of the base 6 is of minor importance in this case. The other vertical axis of rotation is therefore shown with a dashed line, but is not labeled with a reference symbol. Furthermore, this other vertical axis of rotation will not be discussed in more detail below. Whenever an axis of rotation is mentioned below, it always refers to the vertical axis of rotation 7, which is defined by the pivot bearing 5.

[0031] Wherever the terms "axial," "radial," and "tangential" are used below, they generally refer to the vertical axis of rotation 7. "Axial" is a direction parallel to the vertical axis of rotation 7. "Radial" is a direction orthogonal to the axial direction, directly toward or away from the vertical axis of rotation 7. "Tangential" is a direction that is orthogonal to both the axial and radial directions. "Tangential" thus means a direction that, with a constant axial position and at a constant radial distance from the vertical axis of rotation 7, is circular around the vertical axis of rotation 7. If, in exceptional cases, the terms "axial," "radial," and "tangential" are not intended to refer to the vertical axis of rotation 7, the axis to which the terms refer will be explicitly stated.With regard to this axis, which is then explicitly specified, the terms "axial", "radial" and "tangential" are defined in the same way.

[0032] The pivot bearing 5 must be designed to absorb and counteract the tilting moment exerted by the substructure 1 and the elements supported by the substructure 1 (i.e., the lifting mechanism 3, the superstructure 2, the treatment table 4, the person positioned on the treatment table 4, and any other components arranged on the treatment table 4). The pivot bearing 5 is therefore dimensioned accordingly. In particular, the pivot bearing 5 has a relatively large inner diameter d1 and an even larger outer diameter d2.

[0033] To effect a rotational movement of the base 1 about the axis of rotation 7, a drive 8 is arranged on the base 1. The drive 8 acts – for example, via a drive belt 9 – on a drive shaft 10 of a gearbox 11. The drive shaft 10 acts on an output shaft 12 of the gearbox 11. Typically, the gearbox 11 provides a significant reduction ratio of, for example, 100:1 (i.e., 100 revolutions of the drive shaft 10 result in 1 revolution of the output shaft 12). The reduction ratio can also be higher, for example, 120:1 or even more, sometimes even up to 200:1.

[0034] The gearbox 11 is a component distinct from the rotary bearing 5. The gearbox 11 has its own gearbox housing 13. The gearbox housing 13 is fixed to the base 6, for example, by means of screws 14. With respect to the axis of rotation 6, the gearbox housing 13 is located radially within the rotary bearing 5 and axially in the area of ​​the rotary bearing 5. The gearbox housing 13 has a housing diameter d3. The input shaft 10 and the output shaft 12 are mounted in the gearbox housing 13 of the gearbox 11. The housing diameter d3 is smaller than the inner diameter d1 of the rotary bearing 5.

[0035] To rotate the base 1 about the axis of rotation 7, a boom 15 is fixedly mounted on the output shaft 12. The boom 15 is connected to the base 1, so that when the drive shaft 10 (and thus also the output shaft 12) rotates, the boom 15 exerts a torque on the base 1. This causes the base 1 to rotate about the axis of rotation 5. If the gearbox 11 – more precisely, the axis of the output shaft 12 – were arranged exactly coaxially with the axis of rotation 7, a direct, rigid connection between the boom 15 and the base 1 would be easily possible. In practice, however, such coaxiality is not achievable. To overcome this problem, the boom 15 acts on the base 1 via a coupling element 16.The coupling element 16 is designed such that, while the torque exerted on the boom 15 is transmitted to the base 1 (and the base 1 is thereby rotated) by means of the coupling element 16, a radial movement of the boom 16 relative to the base 1 is nevertheless permitted. For example, the coupling element 16 can be configured as shown in . Fig. 2 is designed as a lever that extends essentially tangentially to the axis of rotation and has two ends. In this case, one of the two ends of the lever is pivotally connected to the base 1 and the other to the boom 15.

[0036] The following is related to the Fig. 4 and Fig. Section 5 explains another, alternative possibility for the design of the coupling element 16. According to the Fig. 4 and Fig. In section 5, the coupling element 16 is designed as an elongated slot with a radially extending longitudinal axis 17. A pin 18 of the cantilever 15 is inserted into the elongated slot. The pin 18 extends axially. The pin 18 is matched to the width of the elongated slot so that it can be inserted precisely. In the transverse direction of the elongated slot (corresponding to the current tangential direction), the pin 18 is therefore arranged without play in the elongated slot. In the longitudinal direction of the elongated slot (corresponding to the current radial direction), however, the pin 18 is movable in the elongated slot. An analogous inverse configuration is also possible, in which the elongated slot is part of the cantilever 15 and the pin 18 is part of the coupling element 16.

[0037] The coupling element 16 can also be designed as a tensile / compressive rigid element that is tangentially attached to the end of the lever 15 and also to the substructure 1 by means of a force-fit and / or form-fit connection, for example by means of screws. The coupling element 16 can, for example, be designed as a sheet metal strip that acts as a rigid transmission element in the radial direction of force absorption of the torque, while also being able to compensate for small radial tolerances due to concentricity inaccuracies. Via a force-fit and backlash-free connection, such a coupling element 16 can transmit the torque from the gearbox 11 to the substructure 1 without backlash and rigidly, while simultaneously compensating for small concentricity inaccuracies and is also a very cost-effective element whose rigidity can be determined by the sheet thickness, width, or shape for the respective application.

[0038] The Fig. Figures 1 to 3 describe some advantageous embodiments of the present invention.

[0039] Because the housing diameter d3 is smaller than the inner diameter d1 of the rotary bearing 5, an annular gap 19 is formed between the rotary bearing 5 and the gearbox housing 13. A bushing 20 is arranged in the annular gap 19. A cable 21 is routed from the base 6 to the substructure 1 via the bushing 20. The drive 8 is supplied with electrical energy via the cable 21.

[0040] The base 1 can be rotated between two end positions by means of the drive 8. Fig. Figure 6 shows the two end positions in dashed lines. The two end positions are usually exactly or at least approximately diametrically opposed with respect to the axis of rotation 7. Furthermore, in Fig. Figure 6 shows a mean rotation position between the two end positions, indicated by solid lines. The mean rotation position is preferably (with respect to the angle of rotation) equidistant from, or at least approximately equidistant from, the two end positions. When the base 1 is in the mean rotation position, the gearbox housing 13 is positioned between the other end 1" of the base 1 and the feedthrough 20. Furthermore, according to Fig. 6 (see also) Fig. 2) the drive 8 is arranged between the other end 1' of the substructure 1 and the pivot bearing 5.

[0041] In the design described so far, it is particularly evident in the Fig. 2 and Fig. 3 - The cable 21 is designed as a drag chain. Depending on the direction in which the substructure 1 is rotated by means of the drive 8, the drag chain is placed in or removed from the annular gap 19. Preferably, the cable 21 is also arranged in a protective sheath 22. In this case, the protective sheath 22 is placed in or removed from the annular gap 19 together with the cable 21. The protective sheath 22 can, for example, be designed as a so-called corrugated hose or as a so-called triflex chain. In the case of the protective sheath 22, the cable 21 itself lies loosely in the protective sheath 22.

[0042] The following are related to the Fig. Sections 7 to 10 explain an alternative design for the routing of cable 21 and associated advantageous designs.

[0043] According to Fig. 7 A first end section 23 of the cable 21 is fixedly arranged on the substructure 1. Similarly, a second end section 24 of the cable 21 is arranged in the area of ​​the bushing 20. Furthermore, a cable drum 25 is mounted on the substructure 1. The mounting of the cable drum 25 is such that the cable drum 25 is both translationally movable and rotatable about a drum axis 26 (see Fig. 10) is rotatable. The specific translational path of the cable drum 25 can be linear or curved. It is usually achieved by a corresponding cam guide. The orientation of the drum axis 26 can be as required. Often the drum axis 26 is vertically oriented.

[0044] A specific section of the cable 21 – hereinafter referred to as the drum section – is fixed inside the cable drum 25. The drum section is not shown in the FIG. However, the drum section lies between the first and the second end sections 23, 24. Extending from the drum section is a first intermediate section 27 to the first end section 23. Similarly, extending from the drum section is a second intermediate section 28 to the second end section 24. Thus, looking from the first end section 23 to the second end section 24, and adjacent to each other and to the end sections 23, 24, there is first the first intermediate section 27, then the drum section, and finally the second intermediate section 28.

[0045] The cable drum 25 is wound with the two intermediate sections 27, 28 in such a way that when the cable drum 25 is rotated around the drum axis 26, the cable 21 either unwinds or winds up towards both the first and the second end section 23, 24, depending on the direction of rotation of the cable drum 25. Fig. Figure 8 shows the base 1 in one end position, in which the cable 21 is wound to its maximum extent onto the cable drum 25. Conversely, Figure 8 shows... Fig. 9 the base 1 in the other end position, in which the cable 21 is fully unwound from the cable drum 25. The cable drum 25 is preferably spring-loaded such that it holds the intermediate sections 27, 28 under tension. Alternatively or additionally, a forced rotation of the cable drum 25 can be implemented. An example of such an implementation is a design of the aforementioned cam guide as a rack in conjunction with a gear arranged on the cable drum 25, which meshes with the rack and causes the rotation of the cable drum 25.

[0046] Regardless of the direction of rotation of the cable drum 25, either both intermediate sections 27, 28 are wound onto the cable drum 25 or both intermediate sections 27, 28 are unwound from the cable drum 25. However, it is not possible for one of the two intermediate sections 27, 28 to be wound onto the cable drum 25 and the other to be unwound from the cable drum 25. This is particularly clear from Fig. Figure 10 shows only the cable drum 25 and the intermediate sections 27, 28. The curved path of the first intermediate section 27 can be achieved, for example, by a corresponding guide contour. The guide contour is shown in Fig. 10 not shown.

[0047] Out of Fig. 10. Several advantageous designs of the cable 21 and the cable drum 25 are particularly evident.

[0048] To explain the first advantageous embodiment, a first and a second contact area of ​​the cable drum 25 are defined below. The two contact areas can be static or change depending on the rotational position of the base 1. The first contact area is the location on the cable drum 25 where, towards the first end section 23, a first section of the cable 21 (or the first intermediate section 27) wound onto the cable drum 25 transitions into a section of the cable 21 (or the first intermediate section 27) extending towards the first end section 23. Similarly, the second contact area is the location on the cable drum 25 where, towards the second end section 24, a second section of the cable 21 (or the second intermediate section 28) wound onto the cable drum 25 transitions into a section of the cable 21 (or the second intermediate section 28) extending towards the second end section 24.It is evident that the first contact area and the second contact area are located exactly or at least approximately diametrically opposite each other with respect to the drum axis 26.

[0049] Furthermore, the cable drum 25 has a first collection area 29 and a second collection area 30. The first collection area 29 serves to wind up the first intermediate section 27. Similarly, the second collection area 30 serves to wind up the second intermediate section 28. The collection areas 29 and 30 are clearly offset from each other axially in the direction of the drum axis 26.

[0050] Finally, the cable 21 – just as in the embodiment where the cable 21 is placed in the annular gap 19 – is arranged in a protective sheath 22. In the case of the embodiment of Fig.Steps 7 to 10 involve winding the protective sheath 22 onto or off the cable drum 25 together with the cable 21. Again, the cable 21 itself lies loosely inside the protective sheath 22. The tensile load occurs only in the protective sheath 22.

[0051] The present invention offers many advantages. For example, elements optimally dimensioned for their respective tasks can be used for the rotary bearing 5 and the gearbox 11, resulting in cost optimization. Furthermore, standardized components can be used. The installation space for the rotary bearing 5 and the gearbox 11 can be utilized optimally and flexibly. Due to the low precision requirements of the mounting interfaces, advantages arise with regard to costs, assembly, adjustment, and commissioning testing. The small installation space required, particularly the low overall height, increases the operational flexibility of the RT gantry. The rotary bearing 5 and the gearbox 11 can be mounted and replaced independently of each other.Due to the independent assembly, the rotation of the base 1 in the swivel bearing 5 can initially be carried out manually, i.e., independently of the drive 8 and the gearbox 11, even during the manufacturing of the patient bed. This allows the swivel bearing 5 to be tested first. Similarly, the gearbox 11 can also be tested separately. Whether the cable 21 is configured as a drag chain or a cable drum 25 is used, the required length of cable 21 can be buffered in a simple and space-saving manner. In particular, when using the cable drum 25, the overall height remains low if the drum axis 26 is oriented vertically, because the minimum bending radius of the cable 21 no longer affects the overall height.

[0052] Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by the person skilled in the art without leaving the scope of protection of the invention.

Claims

[1] Patient bed, - wherein the patient bed has a base (1) and a superstructure (2) which are connected to each other via a lifting mechanism (3), - wherein a reclining table (4) is arranged on the superstructure (2) on which an adult person can be reclined, - wherein the substructure (1) is supported at one (1') of its ends (1', 1") by means of a pivot bearing (5) on a base (6) so that the substructure (1) is rotatable about a vertical axis of rotation (7), - wherein the other end (1") of the substructure (1) is not supported, - wherein the lifting mechanism (3) is arranged between one end and the other end (1', 1") of the substructure (1) and under the superstructure (2), - wherein a drive (8) is arranged on the substructure (1) which acts on a drive shaft (10) of a gearbox (11), - wherein a rotation of the drive shaft (10) causes a rotation of an output shaft (12), - wherein the gearbox (11) has a gearbox housing (13) which is arranged non-rotatably on the base (6) and in which the drive shaft (10) and the output shaft (12) are mounted, - wherein a boom (15) is arranged on the output shaft (12) in a rotationally fixed manner and is connected to the base (1), so that when the drive shaft (12) is rotated, the boom (15) exerts a torque on the base (1), causing the base (1) to rotate about the axis of rotation (7), characterized by , - that the gearbox (11) is a component different from the rotary bearing (5), - that the gearbox housing (13), with respect to the axis of rotation (7), is arranged radially within the rotary bearing (5) and axially in the area of ​​the rotary bearing (5) and - that the boom (15) acts on the substructure (1) via a coupling element (16), by means of which the torque exerted on the boom (15) is transferred to the substructure (1), but nevertheless allows a radial movement of the boom (15) relative to the substructure (1). [2] Patient couch according to claim 1, characterized by , that the coupling element (16) is designed as an elongated hole with a radially extending longitudinal axis (17) and that a pin of the cantilever (15) is inserted into the elongated hole or conversely, that the coupling element (16) is designed as a pin which is inserted into an elongated hole with a radially extending longitudinal axis (17) provided in the cantilever (15). [3] Patient couch according to claim 1, characterized by, that the coupling element (16) is designed as a lever extending essentially tangentially to the axis of rotation (7) with two ends and that each of the two ends of the lever is articulated to the substructure (1) and the boom (15). [4] Patient couch according to claim 1, 2 or 3, characterized by , that the rotary bearing (5) has an inner diameter (d1) and the gearbox housing (13) has a housing diameter (d3) and the housing diameter (d3) of the gearbox housing (13) is smaller than the inner diameter (d1) of the rotary bearing (5), so that an annular gap (19) is formed between the rotary bearing (5) and the gearbox housing (13), and that a feedthrough (20) is arranged in the annular gap (19) through which a cable (21) is led from the substrate (6) into the substructure (1), through which the drive (8) is supplied with electrical energy. [5] Patient couch according to claim 4, characterized by, that the base (1) can be rotated between two end positions by means of the drive (8) and that when the base (1) is in a middle rotational position between the two end positions, the gearbox housing (13) is arranged between the other end (1") of the base (1) and the feedthrough (20). [6] Patient couch according to claim 4 or 5, characterized by , that the drive (8) is arranged between the other end (1") of the substructure (1) and the rotary bearing (5). [7] Patient couch according to claim 4, 5 or 6, characterized by , that the cable (21) is designed as a drag chain which, depending on the direction in which the substructure (1) is rotated by means of the drive (8), is laid in the annular gap (19) or removed from the annular gap (19). [8] Patient couch according to claim 7, characterized by, that the cable (21) is arranged in a protective sheath (22) and that the protective sheath (22) together with the cable (21) is placed in or removed from the annular gap (19). [9] Patient couch according to claim 4, 5 or 6, characterized by, that a first end section (23) of the cable (21) is fixedly arranged on the substructure (1) and a second end section (24) of the cable (21) is arranged in the area of ​​the feedthrough (20), that a cable drum (25) is mounted on the substructure (1) so that the cable drum (25) is translationally movable and rotatable about a drum axis (26), that a drum section of the cable (21) which lies between the first and the second end section (23, 24) is fixed inside the cable drum (25) and that when the cable drum (25) is rotated about the drum axis (26), depending on the direction of rotation of the cable drum (25), the cable (21) either unwinds or winds up towards both the first and the second end section (23, 24). [10] Patient couch according to claim 9, characterized by, that a first contact area of ​​the cable drum (25), at which a first section of the cable (21) wound onto the cable drum (25) transitions towards the first end section (23) into a section of the cable (21) extending towards the first end section (23), and a second contact area of ​​the cable drum (25), at which a second section of the cable (21) wound onto the cable drum (25) transitions towards the second end section (24) into a section of the cable (21) extending towards the second end section (24), are approximately diametrically opposite each other with respect to the drum axis (26). [11] Patient couch according to claim 9 or 10, characterized by, that the cable drum (25) has a first collection area (29) for winding up the section (27) of the cable (21) extending from the drum section to the first end section (23) and a second collection area (30) for winding up the section (28) of the cable (21) extending from the drum section to the second end section (24) and that the collection areas (29, 30) are offset from each other in the direction of the drum axis (26). [12] Patient couch according to claim 9, 10 or 11, characterized by , that the cable (21) is arranged in a protective sheath (22) and that the protective sheath (22) is coiled or uncoiled together with the cable (21).

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