CT imaging equipment

Abstract

The present invention relates in particular to a structure of a dental and medical cone beam computed tomography (CBCT) apparatus. The basic structure of the apparatus comprises two elongated frame parts (11, 21), wherein the first frame part (11) is arranged to support an X-ray imaging device (14, 15) and wherein the frame parts (11, 21) are mechanically connected to each other via an articulated structure (22) so as to allow the first frame part (11) supporting the X-ray imaging device (14, 15) to be tilted relative to the second frame part (21).

Description

Technical Field

[0001] The present invention relates to computed tomography imaging apparatus. In particular, the features of the apparatus according to the invention are suitable for use in the context of dental and medical cone beam computed tomography (CBCT) imaging apparatus. Background Art

[0002] Computed tomography (CT) is a type of X-ray imaging in which the volume to be imaged is irradiated from different directions and, from the image information thus obtained, the desired two-dimensional or three-dimensional image can be reconstructed.

[0003] Conventional CT devices are large and bulky, and they are usually installed on the floor. For imaging, the patient is positioned in an inspection opening of the device (usually on an inspection platform that extends horizontally and can be moved laterally).

[0004] Since the development of cone-beam computed tomography (CBCT) technology (which, for example, utilizes lower rotational speeds for imaging devices), devices that are lighter than more traditional CT devices have been developed. CBCT devices also include devices that are not floor-mounted but rather are designed to be mobile. Furthermore, configurations have been devised that include a vertically extending frame and horizontally extending supports for the imaging device.

[0005] In general, considering medical X-ray imaging devices, there are some devices that do not have patient support structures in the device itself, while those devices that include patient support structures are generally designed with imaging of standing patients, sitting patients or lying patients in mind. Summary of the Invention

[0006] The object of the present invention and its preferred embodiments is a CT apparatus, in particular a CBCT apparatus, which is suitable for a variety of uses and enables various parts of the anatomy to be imaged in various ways. The features of the invention are defined in claim 1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention will now be described in more detail with reference to preferred embodiments of the invention and to the accompanying drawings, in which:

[0008] Figure 1 is a schematic general side view showing, by way of example, certain components of a portion of an apparatus according to an embodiment of the invention.

[0009] Figure 2a and Figure 2b Shown to be applicable to Figure 1 Structural details used in the context of the device's slender frame.

[0010] Figure 3aAs an example, it is shown that it is suitable for Figure 1 Some details of the patient support structure used in the device shown in .

[0011] Figure 3b Shown to be applicable in Figure 1 An example of a cross section of a patient support structure used in the apparatus shown in .

[0012] Figure 4 is a schematic general side view showing, by way of example, certain components of an embodiment of the device according to the invention.

[0013] Figure 5 for Figure 4 Schematic general side view of the apparatus of FIG. 1 showing certain components of the construction when driven in an inclined position.

[0014] Figure 6 shows can be used as with e.g. Figure 5 The components of the device shown are functionally related to the arrangement of the shifting and locking mechanisms.

[0015] Figure 7 is a schematic general side view showing, by way of example, another embodiment of certain components of a portion of the apparatus according to the invention.

[0016] Figure 8 To illustrate a block diagram of an example of such components, a control system of the device according to the present invention may be configured to control said components. DETAILED DESCRIPTION

[0017] Figure 1 A schematic general side view of certain components of one embodiment of a portion of an apparatus according to the invention is shown as an example. Figure 1 The dental or medical CT imaging apparatus includes an elongated frame member 11 extending in a first direction and having a first end and a second end. A support structure 12 extends from the elongated frame member 11 in a second direction that is substantially orthogonal to the first direction, the support structure supporting an X-ray source 14 and an image detector 15, wherein the X-ray source and the image detector are arranged in a substantially parallel relationship. Figure 1 The X-ray source 14 and the image detector 15 which together form the X-ray imaging device 14, 15 may be mounted to the support structure 12 essentially opposite each other, however in an embodiment their mutual position may also be arranged to be adjustable.

[0018] Figure 1 Further shown is a patient support 18, which is a structure mechanically connected to the elongated frame member 11 and extending generally parallel to the elongated frame member 11. Figure 1In the embodiment of FIG. 1 , the patient support 18 has substantially the same length as the elongated frame member 11 .

[0019] According to one aspect, for example, the length of the elongated frame member 11 is approximately 240 centimeters.

[0020] According to one aspect, for example, the length of the elongated frame member 11 is between 220 centimeters and 260 centimeters.

[0021] According to one aspect, for example, the length of the patient support 18 is 80-90% of the length of the elongated frame member 11 .

[0022] According to one aspect, for example, the patient support 18 has a longer dimension along a first direction and a shorter dimension along a second direction orthogonal to the first direction.

[0023] According to one aspect, for example, the patient support 18 is radiolucent at least along the first direction, at least for a major portion thereof.

[0024] According to one aspect, for example, the radiolucent portion of the patient support 18 has substantially the same length as the elongated frame member 11 .

[0025] According to one aspect, for example, the patient support 18 includes a radiopaque section at least at either of its ends in the first direction.

[0026] According to one aspect, for example, the length of the radiolucent portion of the patient support 18 along the first direction is 80-90% of the length of the elongated frame member 11 .

[0027] According to one aspect, for example, the support structure 12 supporting the X-ray imaging devices 14, 15 is a circular gantry having a central axis 13. The gantry may partially surround or completely house the X-ray imaging devices 14, 15.

[0028] according to Figure 1 In one aspect not directly visible in the drawing, for example, the apparatus comprises a drive mechanism 16 arranged to drive the X-ray imaging devices 14, 15 about an axis of rotation. This axis of rotation may coincide with the central axis 13 of the support structure 12 in the form of a gantry, and it may be a physical axis, or a rotation axis such as Figure 1 The virtual axis of rotation in the case of .

[0029] According to one aspect, for example, when the X-ray imaging devices 14, 15 are driven along a curved path, the central axis 13 of the gantry coincides with the rotation center / axis of rotation of the X-ray imaging devices.

[0030] According to one aspect, the axis of rotation is an instantaneous (virtual) axis of rotation, and the position of the instantaneous axis of rotation relative to the central axis 13 can be arranged to be varied.

[0031] According to one aspect, at least one of the two components, the radiation source 14 and the image detector 15 , is arranged to be movable laterally from a position diametrically opposite the other component.

[0032] According to one aspect, the structure 12 supporting the X-ray imaging devices 14 and 15 includes a gantry having a central axis, and the structure of the apparatus permits at least one of: lateral movement of the X-ray source 14 between a position where a central ray generated by the X-ray source 14 coincides with the central axis of the gantry and a position where the central ray generated by the X-ray source 14 does not coincide with the central axis of the gantry; and lateral movement of the image detector 15 between a position where a vector perpendicular to a surface of the image detector 15 at a center coincides with the central axis of the gantry and a position where the vector perpendicular to the surface of the image detector 15 at a center does not coincide with the central axis of the gantry. The lateral movement of the X-ray imaging devices 14 and 15 may include moving the X-ray imaging devices 14 and 15 to a position where they face each other, with the central ray generated by the X-ray source 14 not coinciding with the central axis of the gantry and the vector perpendicular to the surface of the image detector 15 at a center not coinciding with the central axis of the gantry.

[0033] According to another aspect, a further drive mechanism 17 is arranged to the apparatus to enable the support construction to be moved back and forth in a direction substantially parallel to the direction of extension of the elongated frame member 11. According to one aspect, the drive mechanism 17 may be arranged to move the support construction 12 along or alongside the elongated frame member 11.

[0034] In accordance with Figure 2a In the example of FIG, the drive mechanism 17 of the support structure 12 discussed above comprises a motor 110 and a gear arrangement 111 arranged to rotate a pulley 112. Figure 2a In the configuration shown as one embodiment, while the motor 110 and pulley 112 are located near the second end of the elongated frame member 11, there is another pulley 112' near the first end of the elongated frame member 11, and around the pulleys 112, 112' is a belt 113 or a chain-like member that performs a corresponding function. The mechanism is then functionally connected to the support structure 12 to drive the support structure along the elongated frame member 11, such as for example in Figure 2b, where a slot 114 is arranged to the elongated frame member 11 and a protruding member 121 is arranged to the support structure 12, said protruding member being fitted to slide along the slot 114. In one embodiment, to minimize friction, a roller type linear guide is used, where the movement is rolling rather than sliding.

[0035] According to one aspect not shown in any of the figures, for example, the drive mechanism for driving the support structure 12 comprises a motor arranged to the support structure 12 itself.

[0036] Regardless of the construction details of the drive mechanism 17 used to drive the support structure 12 along the slender frame member 11 or beside the slender frame member 11, in one embodiment, the construction of the device allows the support structure 12 to be driven along substantially the entire length between the first end and the second end of the slender frame member 11.

[0037] According to yet another aspect and as Figure 1 As shown in , the apparatus comprises connecting formations 19 , 20 connecting the patient support 18 to the elongate frame member 11 .

[0038] According to another aspect, and Figure 3a , an example of which is shown in , the apparatus comprises connection formations 19 , 20 which mechanically connect the patient support 18 to the elongated frame member 11 .

[0039] The connection formations 19 , 20 may include patient support adjustment mechanisms 19 ′, 20 ′ configured to enable displacement of the patient support 18 closer to and further away from the elongated frame member 11 .

[0040] According to another aspect, the drive mechanism 19 ″, 20 ″ is arranged in functional connection with the patient support adjustment mechanism 19 ′, 20 ′.

[0041] According to another aspect, the patient support adjustment mechanism 19', 20' may include a first adjustment mechanism 19' and a second adjustment mechanism 20', wherein the first adjustment mechanism together with its drive mechanism 19" included in the drive mechanism 19", 20" is roughly arranged at the first end of the slender frame part 11, and the second adjustment mechanism together with its drive mechanism 20" included in the drive mechanism 19", 20" is roughly arranged at the second end of the slender frame part 11.

[0042] According to one aspect, for example, the patient support adjustment mechanisms 19 ′, 20 ′ are arranged in functional connection with a control system of the apparatus, and the control system is configured to control the drive mechanisms 19 ″, 20 ″ of the adjustment mechanisms 19 ′, 20 ′.

[0043] According to one aspect, for example, the control system is configured to control connection structures 19, 20, which include a first adjustment mechanism 19' and its drive mechanism 19" roughly arranged at the first end of the slender frame part 11, and a second adjustment mechanism 20' and its drive mechanism 20" roughly arranged at the second end of the slender frame part 11, so as to maintain the same distance between the slender frame part 11 and the patient support 18 at the first and second ends of the slender frame part 11 when adjusting the distance between the slender frame part 11 and the patient support 18.

[0044] According to another aspect, the distance between each end of the elongated frame member 11 and the patient support 18 may be adjusted to be different. According to one aspect, the first and second adjustment mechanisms 19', 20' are arranged to be independently controlled.

[0045] According to one aspect, Figure 3b As shown in , considering the above-mentioned first orientation of the patient support structure 18 , the cross section of its main part is curved in order to better support the patient against the concave surface of the patient support structure 18 .

[0046] According to another aspect, Figure 3b As shown in FIG, at an edge 181 of the cross-section of the patient support structure 18, the shape of the cross-section becomes curved in the opposite direction.

[0047] According to another aspect, and as Figure 3b As further shown in FIG, near the edge of the above-mentioned cross-section of the patient support structure 18, and on the side opposite the concave surface of its main portion, a retaining structure 182 is arranged. The retaining structure 182 can be, for example, an elongated handle or attachment structure to receive a strap designed to extend on or over the concave side of the patient support structure 18 to provide further support for the patient and thereby help keep him still during the imaging exposure.

[0048] Go to Figure 4 , Figure 4 As a general side schematic view certain parts of an embodiment of the device according to the invention are shown by way of example, wherein in addition to the first elongated frame part 11 which may be mentioned as discussed above, there is also a second elongated frame part 21 mechanically connected to the first elongated frame part 11, said second elongated frame part having substantially the same length as the first elongated frame part 11.

[0049] According to one aspect and still with reference to Figure 4A hinged connection structure 22 is arranged near the first end of the first elongated frame member 11, 12 to mechanically connect the first and second elongated frame members 11, 21 so as to allow the first elongated frame member 11 to tilt relative to the second elongated frame member 21 about at least one tilt axis. The at least one tilt axis is orthogonal to the first and second extension directions of the elongated frame member 11 and the support structure 12. Or, in other words, the tilt axis can be an axis that is orthogonal to the direction in which the first and second elongated frame members 11, 21 extend and is orthogonal to the direction in which the support structure 12 for the X-ray imaging assembly 14, 15 extends vertically from the longitudinally extending first frame member 11.

[0050] In the embodiment shown in the figures and discussed in more detail in this application, the at least one tilting axis is horizontal. This should not be understood as meaning that the tilting axis must be horizontal.

[0051] According to another aspect, on the side of the second elongated frame member 21, Figure 4 A mounting structure 23, not directly visible in the drawing, is arranged in connection with the hinged connection formation 22. The mounting structure 23 is arranged to be movable along or alongside the second elongated frame member 21.

[0052] According to another aspect, for example, a locking mechanism 24 is disposed near the second end of the second elongated frame member 21, the locking mechanism being configured to connect and disconnect the first and second elongated frame members 11, 21. In particular, the locking mechanism 24 can be disposed near the second ends of the first and second elongated frame members 11, 21, the locking mechanism being configured to connect and disconnect the first and second elongated frame members 11, 21 near their second ends.

[0053] When the second elongated frame member 21 is stably mounted and the locking mechanism 24 does not connect the first and second elongated frame members 11, 21, the second end of the first elongated frame member 11 is free to move laterally, while the hinged connection 22 between the frame members 11, 21 allows the first elongated frame member 11 to rotate about a horizontal tilt axis near the first end of the first elongated frame member 11. Such a movably arranged mounting structure as described above allows the first end of the first elongated frame member 11 to be lowered and raised with the vertical starting position.

[0054] Figure 5 Show the basis Figure 4The apparatus is at a stage where the first end of the first elongated frame member 11 has moved downwardly and the second end of the first elongated frame member 11 has moved horizontally on the surface. The apparatus may be configured to allow the first end of the first elongated frame member 11 to descend until it is adjacent to the second end of the second elongated frame member 21.

[0055] According to Figure 4 and Figure 5 In a further aspect not directly visible in the drawings, a drive mechanism 27 is arranged in functional connection with the second elongated frame member 21 for driving the mounting structure 23 along or beside the second elongated frame member 21. When mechanically connected to the first elongated frame member 11, the drive mechanism 27 can move the first end of the first elongated frame member 11 in the extension direction of the second elongated frame member 21, near the first end of the first elongated frame member.

[0056] The drive mechanism 27 for driving the mounting structure 23 may be of similar construction to the drive mechanism 17 that drives the support structure 12 of the X-ray imaging device 14 , 15 along or beside the first elongated frame member 11 .

[0057] According to one aspect, the drive mechanism 27 for driving the mounting structure 23 comprises a chain drive.

[0058] In other words, in order to describe some of the features discussed above, in an embodiment, a mounting structure 23 mechanically connected to the hinged connection structure 22 is arranged on the side of the second slender frame part 21, and the mounting structure is arranged to be able to move along the second slender frame part 21 or beside the second slender frame part 21, thereby providing the hinged connection structure 23 and the first end of the first slender frame part 11 mechanically connected to the hinged connection structure 23 with freedom of movement along the second frame part 21 or beside the second frame part 21.

[0059] In one embodiment, the mounting structure 23 is arranged to be movable along or alongside the second elongated frame member 21 a distance at least substantially corresponding to the length of the first elongated frame member 11, and the hinged connection structure 22 is arranged to allow the first elongated frame member 11 to tilt between an orientation in which the first and second elongated frame members 11, 21 extend substantially parallel to each other and an orientation in which the first and second elongated frame members 11, 21 extend substantially orthogonally.

[0060] According to yet another aspect, the locking mechanism 24 includes a displacement mechanism 25, not directly visible in the figures discussed thus far, to move the second end of the first elongated frame member 11 a distance away from the second elongated frame member 21 when the locking mechanism 24 disconnects the first and second elongated frame members 11, 21.

[0061] According to one aspect not shown in detail in the figures discussed so far, the locking mechanism 24 comprises a motor drive arrangement having mating members on the sides of the motorisation structure and the first elongated frame part 11 respectively.

[0062] The locking mechanism 24 may further include a guide structure configured to guide the second end of the first elongated frame member 11 all the way to the locking mechanism 24 when the second end of the first elongated frame member 11 moves toward the locking mechanism 24. In other words, when the second end of the first elongated frame member 11 moves toward the second end of the second elongated frame member 21 and approaches the second end of the second elongated frame member.

[0063] According to yet another aspect, and as exemplified in Figure 4 and Figure 5 As shown in FIG, the first elongated frame member 11 includes at least one wheel or roller 26 near its second end.

[0064] According to another aspect, instead of wheels or rollers, a structure designed to slide on a surface may be arranged at the second end of the first elongated frame member 11 .

[0065] More detailed examples of some of the features discussed above are described in Figure 6 As shown in Figure 6 The second ends of the first and second elongated frame members 11 , 21 are generally shown, however with the very end of the second end of the first elongated frame member 11 cut away, partly completely cut away and partly only one wall cut away so that what may be called the rear wall 11 ′ remains visible.

[0066] Figure 6 The embodiment shown in FIG includes a structure in which the shifting mechanism 25 includes two racks 31 and two gears 32. The two racks are mounted near the second end of the second elongated frame member 21 and extend substantially perpendicular to the direction in which the second elongated frame member 21 extends. The two gears are mounted near the second end of the first elongated frame member 11. The gears 32 are configured to fit with the racks 31. Although two racks and gears are shown, their number may be only one, or two or more.

[0067] Figure 6The embodiment shown in further comprises a shifting mechanism 25 comprising a shifting motor 33 which is arranged in functional connection with a gear 32 .

[0068] According to one embodiment, in order to operate the shifting mechanism 25, the control system of the device can be configured to, when the first and second slender frame parts 11, 21 extend substantially parallel and in response to a control signal that changes the relative orientation of the first and second slender frame parts 11, 21, first operate the shifting mechanism 25 to move the second end of the first slender frame part 11 a distance away from the second end of the second slender frame part 21, and secondly, operate the third drive mechanism 27 to drive the mounting structure 23 along the second slender frame part 21 or beside the second slender frame part 21 toward the second end of the second slender frame part 21 so as to move the second end of the first slender frame part 11 a greater distance away from the second end of the second slender frame part 21.

[0069] Figure 6 The locking mechanism 24 shown in FIG further includes a sensing element 29 configured to detect when the second end of the first elongated frame member 11 has reached a predetermined locking position as the second end of the first elongated frame member 11 moves toward the second end of the second elongated frame member 21 .

[0070] Figure 6 The locking mechanism 24 shown in the figure further includes a locking actuator 28, and the control system of the device can be configured to respond to a control signal from the sensing element 29 that the second end of the first slender frame part 11 has reached a predetermined locking position when moving toward the second end of the second slender frame part 21, and send a control signal to the locking actuator 28 to lock the second end of the first slender frame part 11 at the predetermined locking position.

[0071] according to Figure 6 The guide structure of the embodiment includes two guide rails 30, which are mounted from their first ends near the second end of the second elongated frame member 21 and extend substantially orthogonally to the extension direction of the second elongated frame member 21 to form two guide channels. Figure 6 Two guide rails 30 are shown in FIG, but the number of guide rails can also be other numbers - however, it may be difficult to form a channel with a true guiding function using only one guide rail.

[0072] Although Figure 61 shows that the first elongated frame member 11 includes two wheels or rollers 26 at a first distance from each other near its second end, and the guide structure includes two guide rails 30 to form two guide channels substantially at the same first distance from each other, but the guide rails 30 also include inclined surfaces at their second ends so that the distance between the guide channels is less than the first distance at the end of the channel. Such a structure helps guide the second end of the first elongated frame member 11 to find the designed channel to move toward the second elongated frame member 21.

[0073] According to one aspect, for example and as Figure 7 , the support structure 12 in the form of a gantry for the imaging devices 14, 15 does not substantially completely surround the imaging devices 14, 15, but serves primarily or exclusively as a support structure for holding the imaging devices 14, 15 and as a support structure for a structure arranged to the gantry for driving the imaging devices 14, 15 about an axis. This solution enables a gantry that is lighter and provides better access to the volume between the imaging devices 14, 15, both physically and in terms of areas where a clear line of sight to this volume is possible.

[0074] Figure 8 Examples of components of a control system suitable for use in an apparatus according to the present disclosure are shown as block diagrams. In various embodiments, not all of these features must be present in the control system of the apparatus. Figure 8 The control system is configured to control the operation of the X-ray source and the image detector. The components for controlling the operation of the X-ray source and the image detector may include components physically arranged to the X-ray source and / or the image detector and / or arranged elsewhere in the device.

[0075] Figure 8 The control system further controls various drive means of the apparatus, such as those which move the imaging apparatus supported by the support structure, the support structure itself and the adjustment mechanism of the patient support. As described above, the control system may also control, for example, the drive of the mounting structure. Further, where the apparatus includes a motorized locking mechanism for connecting and disconnecting the first and second elongated frame members, the control system may also control the drive means of the locking mechanism, such as the shift motor and locking actuator discussed above. In general, the control system may be arranged to control all of the operations discussed above or any part thereof. The input to the control system may be provided by a remote control. The structures and functions discussed above provide various possibilities for positioning and imaging the patient.

Claims

1. A medical CT imaging device comprising: - a first elongated frame member (11) extending in a first direction and comprising a first end and a second end; - a support structure (12) extending from the first elongated frame member (11) in a second direction substantially orthogonal to the first direction; - an X-ray source (14) and an image detector (15) mounted to the support structure (12), the X-ray source and the image detector together forming an X-ray imaging device (14, 15); - a first drive mechanism (16) arranged to move the imaging device (14, 15) about an axis (13); - a second drive mechanism (17) arranged to move the support structure (12) in a direction substantially parallel to the first direction in which the first elongated frame member (11) extends; - a patient support (18); - control systems; Characterized in that the device includes a second slender frame part (21), the second slender frame part including a first end and a second end and having substantially the same length as the first slender frame part (11), wherein a hinged connection structure (22) is arranged near the first end of the first slender frame part (11) to mechanically connect the first slender frame part (11) and the second slender frame part (21) to allow the first slender frame part (11) to tilt relative to the second slender frame part (21) about at least one tilting axis, the at least one tilting axis being orthogonal to both the first direction and the second direction.

2. The device according to claim 1, characterized in that A mounting structure (23) mechanically connected to the hinged connection structure (22) is arranged on a side of the second slender frame part (21), and the mounting structure is arranged to be able to move along the second slender frame part (21) or beside the second slender frame part, thereby providing the hinged connection structure (22) and the first end of the first slender frame part (11) mechanically connected to the hinged connection structure (22) with freedom of movement along the second slender frame part (21) or beside the second slender frame part.

3. The device according to claim 2, characterized in that The mounting structure (23) is arranged to be movable along or alongside the second elongated frame member (21) a distance at least substantially corresponding to the length of the first elongated frame member (11), and the hinged connection structure (22) is arranged to allow the first elongated frame member to tilt between an orientation in which the first elongated frame member (11) and the second elongated frame member (21) extend substantially parallel to each other and an orientation in which the first elongated frame member (11) and the second elongated frame member (21) extend substantially orthogonally.

4. The device according to claim 2 or 3, characterized in that The apparatus comprises a third drive mechanism (27) for driving the mounting structure (23) along or alongside the second elongated frame member (21).

5. The device according to claim 1, characterized in that The patient support (18) is a structure mechanically connected to the first elongated frame member (11) and extending substantially parallel to the first elongated frame member (11) in the first direction.

6. The device according to claim 5, characterized in that The patient support (18) has substantially the same length as the first elongated frame member (11).

7. The device according to claim 5 or 6, characterized in that The patient support (18) includes a radiolucent portion having substantially the same length as the first elongated frame member (11).

8. The device according to claim 1, characterized in that A locking mechanism (24) is arranged near the second ends of the first slender frame part (11) and the second slender frame part (21), and the locking mechanism is configured to connect and disconnect the first slender frame part (11) and the second slender frame part (21) near their second ends; the locking mechanism includes a shifting mechanism (25) configured to move the second end of the first slender frame part (11) away from the second end of the second slender frame part (21) when the locking mechanism (24) disconnects the first slender frame part (11) and the second slender frame part (21), and the device includes a third driving mechanism (27) to drive the second slender frame part (21) along or beside the second slender frame part. The mounting structure (23), and the control system are configured to, when the first slender frame part (11) and the second slender frame part (21) extend substantially parallel and in response to a control signal for changing the mutual orientation of the first slender frame part (11) and the second slender frame part (21), first operate the shifting mechanism (25) to move the second end of the first slender frame part (11) a distance away from the second end of the second slender frame part (21), and secondly operate the third drive mechanism (27) to drive the mounting structure (23) toward the second end of the second slender frame part (21) along or beside the second slender frame part so as to move the second end of the first slender frame part (11) a greater distance away from the second end of the second slender frame part (21).

9. The device according to claim 8, characterized in that The shifting mechanism (25) includes at least one rack (31) and at least one gear (32), wherein the at least one rack is mounted near the second end of the second slender frame member (21) and extends substantially perpendicular to the direction in which the second slender frame member (21) extends, and the at least one gear is mounted near the second end of the first slender frame member (11) and is configured to be adapted to the rack (31).

10. The device according to claim 9, characterized in that The shifting mechanism (25) comprises a shifting motor (33) which is arranged in functional connection with the at least one gear (32).

11. The device according to any one of claims 8 to 10, characterized in that The locking mechanism (24) includes a sensing element (29) configured to detect when the second end of the first elongated frame member (11) has reached a predetermined locking position as the second end of the first elongated frame member (11) moves toward the second end of the second elongated frame member (21).

12. The device according to claim 11, characterized in that The locking mechanism (24) includes a locking actuator (28), and the control system is configured to send a control signal to the locking actuator (28) to lock the second end of the first slender frame member (11) at the predetermined locking position in response to a control signal from the sensing element (29) indicating that the second end of the first slender frame member (11) has reached the predetermined locking position when moving toward the second end of the second slender frame member (21).

13. The device according to claim 8, characterized in that The locking mechanism (24) includes a guiding structure configured to guide the second end of the first elongated frame member (11) all the way to the locking mechanism (24) when the second end of the first elongated frame member (11) moves toward the second end of the second elongated frame member (21) and approaches the second end of the second elongated frame member.

14. The device according to claim 13, characterized in that The guide structure includes at least one guide rail (30), which is mounted at its first end near the second end of the second slender frame member (21) and extends substantially orthogonally to the direction in which the second slender frame member (21) extends to form at least one guide channel.

15. The device according to any one of claims 1 to 3, characterized in that The first elongated frame member (11) includes at least one wheel or roller (26) adjacent its second end.

16. The device according to claim 13 or 14, characterized in that The first elongated frame member (11) comprises two wheels or rollers (26) at a first distance from each other near its second end, and the guide structure comprises at least two guide rails (30) to form two guide channels substantially at the first distance from each other, wherein the at least two guide rails (30) comprise inclined surfaces at their second ends so that the distance between the guide channels is smaller than the first distance at the second ends of the channels.

17. The device according to any one of claims 1 to 3, characterized in that The first elongated frame member (11) includes a structure near its second end designed to slide on a surface.

18. The device according to any one of claims 1 to 3, characterized in that Driving the support structure (12) in a direction substantially parallel to the first direction is arranged to be possible for substantially the entire length of the first elongated frame member (11) between the first end and the second end.

Images