HYDRAULIC LIFTING COLUMN

Abstract

A hydraulic lifting column comprising a base structure, a head structure and a lifting structure. The lifting structure comprising a hydraulic power unit and hydraulic linear actuators extending between the base structure and the head structure, the hydraulic power unit acting on the hydraulic linear actuators. The lifting structure comprising four linear actuator units with a mutually parallel, vertically oriented working direction. Each linear actuator unit comprising a double cylinder having two-cylinder bores arranged next to one another and two piston structures with piston rods oriented parallel to one another and extendable in opposite directions from the double cylinder. The four lower piston rods are connected to the base structure at the corners of a first quadrilateral and the four upper piston rods are connected to the head structure at the corners of a second quadrilateral.

Claims

1. A Hydraulic Lilting column comprising: a base structure; a head structure; and a lifting structure, wherein the lifting structure comprising a hydraulic power unit and hydraulic linear actuators extending between the base structure and the head structure, the hydraulic power unit acting on the hydraulic linear actuators; the lifting structure comprising four linear actuator units with a mutually parallel, vertically oriented working direction; each linear actuator unit comprising a double cylinder having two cylinder bores arranged next to one another and two piston structures with piston rods oriented parallel to one another and extendable in opposite directions from the double cylinder; and four lower piston rods are connected to the base structure at the corners of a first quadrilateral and four upper piston rods are connected to the head structure at the corners of a second quadrilateral.

2. The Hydraulic Lifting column according to claim 1, wherein the four linear actuator units form the only geometrical guide of the head structure relative to the base structure.

3. The Hydraulic Lilting column according to claim 2, wherein the first quadrilateral is larger in area than the second quadrilateral.

4. The Hydraulic Lilting column according to claim 3, wherein double cylinders each have a one-piece base body in which the two cylinder bores are formed.

5. The Hydraulic, Lifting column according to claim 4, wherein four double cylinders are part of a fixed cylinder assembly, the cylinder assembly further comprising the hydraulic power unit.

6. The Hydraulic Lifting column according to claim 5 wherein a tank being part of the hydraulic power unit connects two double cylinders to one another, thereby stiffening them against one another.

7. The Hydraulic Lifting column according to claim 6, wherein the cylinder assembly comprises a circumferential stiffening structure which extends over the four double cylinders and connects them to one another, the circumferential stiffening structure comprising struts which extend at the periphery of the cylinder assembly and which connect respectively two double cylinders to one another.

8. The Hydraulic Lifting column according to claim 7, wherein the double cylinders are stiffened diagonally crosswise against one another.

9. The Hydraulic Lifting column according to claim 8, wherein the cylinder assembly comprises a base plate on which the double cylinders are disposed, the motor-pump unit of the hydraulic power unit being disposed between the double cylinders on the base plate.

10. The Hydraulic Lifting column according to claim 9. wherein the hydraulic power unit acts on the respective linear actuator units in hydraulic parallel connection, a flow divider being connected downstream of the motor-pump unit of the hydraulic power unit.

11. The Hydraulic Lifting column according to claim 10, wherein at least one check valve, a hydraulically pivotable non-return valve, is arranged in the hydraulic connection of the motor-pump unit of the hydraulic power unit with the group of linear actuator units which can be acted upon by the motor-pump unit.

12. The Hydraulic Lifting column according to claim 11, wherein the head structure has a lying surface suspension, a head frame to which the four upper piston rods are fastened, a crosshead and a bearing unit, the crosshead is pivotably mounted on the head frame about a first pivot axis and the bearing unit is pivotally mounted on the crosshead about a second pivot axis, and the first pivot axis and the second pivot axis intersect each other and/or wherein the lying surface suspension is a cardanic lying surface suspension.

13. The Hydraulic Lifting column according to claim 12, wherein the lying surface suspension has a first swivel drive effective between the head frame and the crosshead and a second swivel drive effective between the crosshead and the bearing unit, wherein the two swivel drives are provided as linear drives and are arranged within the space enclosed by the four upper piston rods.

14. The Hydraulic Lifting column according to claim 13, wherein a first swivel drive carrier projects downwards from the head frame, and/or a second pivot drive carrier projects downwards from the crosshead, and a steering arm, on which the first pivot drive acts, projects from the second pivot drive carrier.

15. The Hydraulic Lifting column according to claim 14, wherein each linear actuator unit comprises a single hydraulic cylinder instead of a double cylinder and two piston structures with piston rods oriented parallel to one another and extendable in opposite directions from the double cylinder, the piston rod of which acts as an upper piston rod or as a lower piston rod depending on the mounting position of the respective linear actuator unit and thus the fixing of the respective cylinder part to the base structure or, alternatively, to the head structure.

16. The Hydraulic Lifting column according to claim 1, wherein The Lifting column is an operating table.

17. The Hydraulic Lifting column according to claim 1, wherein the first quadrilateral is larger in area than the second quadrilateral.

18. The Hydraulic Lifting column according to claim 1, wherein double cylinders each have a one-piece base body in which the two-cylinder bores are formed.

19. The Hydraulic Lifting column according to claim 2, wherein double cylinders each have a one-piece base body in which the two-cylinder bores are formed.

20. A Lifting structure comprising: a hydraulic power unit and hydraulic linear actuators extending between a base structure and a head structure, the hydraulic power unit acting on the hydraulic linear actuators; the lifting structure comprising four linear actuator units with a mutually parallel, vertically oriented working direction; each linear actuator unit comprising a double cylinder having two-cylinder bores arranged next to one another and two piston structures with piston rods oriented parallel to one another and extendable in opposite directions from the double cylinder; and the four lower piston rods are connected to the base structure at the corners of a first quadrilateral and the four upper piston rods are connected to the head structure at the corners of a second quadrilateral.

Description

[0022] In the following, this invention will be explained in more detail by describing two preferred exemplary embodiments. Thereby

[0023] FIG. 1 is a perspective overall view diagonally from above of a first hydraulic lifting column according to the invention,

[0024] FIG. 2 is a detailed view diagonally from above of the head structure of a second hydraulic lifting column according the invention,

[0025] FIG. 3 is a first detailed side view of the head structure according to FIG. 2,

[0026] FIG. 4 is a second detailed side view of the head structure according to FIGS. 2 and 3,

[0027] FIG. 5 is a third detailed side view of the head structure according to FIGS. 2 to 4,

[0028] FIG. 6 is a first detail view diagonally from below of the head structure according to FIGS. 2 to 5 and

[0029] FIG. 7 is a second detail view diagonally from below of the head structure according to FIGS. 2 to 6.

[0030] The hydraulic lifting column illustrated in FIG. 1 comprises a base structure 1, a head structure 2 and a lifting structure 3 extending between the base structure 1 and the head structure 2. The base structure 1 is illustrated as base plate 4. And the head structure 2 is shown in a corresponding way as head plate 5. Other configurations of the base structure 1 and the head structure 2, specifically adapted to the respective application, are possible, as will be explained in more detail below with reference to the exemplary embodiment illustrated in detail in FIGS. 2 to 7.

[0031] The lifting structure 3 is of hydraulic type. It thus has hydraulic linear actuators and a hydraulic power unit acting upon them, which in turn comprises an electrically driven motor-pump unit 6 and a tank 7. In implementation of the present invention, the lifting structure 3 comprises four linear actuator units 8, each of these four linear actuator units 8 comprising a double cylinder 9 having two parallel cylinder bores 10 and two piston structures 11 with pistons 12 sealingly guided in said cylinder bores 10, the double cylinders 9 each having a one-piece body 13 and an upper end plate 14 connected thereto, the two cylinder bores 10 being formed in the one-piece body 13.

[0032] The two piston structures 11 of each linear actuator unit 8 are also oriented parallel to each other in accordance with the two cylinder bores 10. They have extendable piston rods 15, namely a lower piston rod 15u and an upper piston rod 15o, which can be extended in opposite directions from the double cylinder 9. In each double cylinder 9, the two working chambers 16, which are supplied with hydraulic fluid to extend the assigned piston rod 15, communicate constantly with each other via a connecting line, so that the two cylinders of each double cylinder are coupled to each other in hydraulic parallel connection.

[0033] In accordance with the parallel offset of the two cylinder bores 10 of each double cylinder 9, the assigned piston rods 15 are also offset parallel to each other. The upper piston rod 15o exits from the double cylinder 9 through a hole provided in the upper end plate 14 of the respective double cylinder 9. The four lower piston rods 15u are rigidly connected to the base plate 4 at the corners of a first quadrilateral, and the four upper piston rods 15o are rigidly connected to the head plate 5 at the corners of a second quadrilateral, which is smaller than the first quadrilateral. The corresponding fixing screws 17 are illustrated.

[0034] The four double cylinders 9 are part of a rigid cylinder assembly 18 of approximately cuboid basic shape. For this purpose they are mounted on a rectangular base plate 19with parallel, vertically oriented working directionin its corner areas. The cylinder assembly 18 also comprises a circumferential stiffening structure 20 extending over and connecting the four double cylinders 9, which is realized by four struts 21 connecting two adjacent double cylinders 9 in their upper end area.

[0035] The cylinder assembly 18 also includes the hydraulic power unit used to pressurize the four linear actuator units. For this purpose, the motor-pump unit 6 of the hydraulic power unit is mounted between the double cylinders 9 on the base plate 19 of the cylinder assembly 18. A tank 7 belonging to the hydraulic power unit is arranged between two adjacent double cylinders 9. Part of tank 7 is a sheet 22, which connects the two adjacent double cylinders 9, stiffening them against each other.

[0036] Hydraulic lines are integrated into the base plate 19, which hydraulically connect the motor-pump unit 6 of the hydraulic power unit on the one hand with the tank 7 and on the other hand with the four double cylinders 9. The hydraulic connection of the motor-pump unit 6 with the four linear actuator units 8 is such that the latter are acted upon by the hydraulic power unit via a downstream flow divider in hydraulic parallel connection.

[0037] The base structure and the lifting structure 3 of the hydraulic lifting column illustrated in FIGS. 2 to 7in each case only to the extent of the upper sectionare essentially identical to the lifting column according to FIG. 1, so that reference is made to the above explanations in this respect and the graphic representation can essentially be limited to the illustration of the specific head structure 2. With regard to said head structure 2, there are the relevant differences to the embodiment according to FIG. 1 explained below.

[0038] According to FIGS. 2 to 7, the head structure 2 comprises a cardanic lying surface suspension 23, comprising a head frame 24 to which the four upper piston rods 15o are attached, a crosshead 25 and a bearing unit 26 which supports a patient lying surface and thus forms a mechanical interface. The head frame 24which has an openinghas a rectangular basic shape. The crosshead 25, which is arranged within the opening of the head frame 24, is mounted on the head frame 24 so that it can be pivoted about a first pivot axis X. For this purpose, two cylindrical receptacles 27 aligned with each other are designed on the head frame 24, in which bearing pins 28 are fixed, on whichvia corresponding bearing bushes 29the crosshead 25 is pivotably mounted. The bearing unit 26 is pivoted on the crosshead 25 around a second pivot axis Y, which cuts the first pivot axis X at a right angle. It comprises two supporting bodies 30, 31, which are rigidly connected to each other via a shaft 32 which passes through the crosshead 25 and which is mounted in the crosshead to rotate about the second pivot axis Y. Each of the two support bodies 30, 31 has two bearing surfaces 33 for the patient lying surface to be placed on the lying surface suspension 23; the corresponding fastening screws 34 are also illustrated as examples.

[0039] The lying surface suspension 23 also has a first swivel drive 35 between the head frame 24 and the crosshead 25 in the form of a hydraulic linear actuator 36. Its cylinder part 37 is articulated to a first swivel drive carrier 38 projecting downwards from the head frame 24. The associated piston rod 39 engages a steering arm 40 and is articulated thereto, wherein the steering arm 40 projects from a second swivel drive carrier 41, which in turn projects downwards from the crosshead 25. A stiffening bar 42 of the crosshead 25 can also be seen, which protrudes from the second swivel drive beam 41 opposite the steering arm 40. The cylinder part 43 of a second swivel drive 45 - also provided as a hydraulic linear actuator 44is hingewise connected to the second swivel drive carrier 41, which is effective between the crosshead 25 and the bearing unit 26 in such a way that the respective piston rod 46 is connected in an articulated manner and engages one of the two supporting bodies, namely the supporting body 31. The two hydraulic linear actuators 36, 44 are double-acting, so that their piston rods 39, 46 can be actively extended and retracted under the corresponding pressure of the two working chambers. Thus the crosshead 25 can be pivoted about the first pivot axis X in relation to the head frame 24 under the action of the first swivel drive 35. And under the action of the second swivel drive 45, the bearing unit 26 can be pivoted about the second pivot axis Y with respect to the crosshead 25.

[0040] The two swivel drives 35, 45 are arranged in such a way that when the head structure 2 is loweredwith the upper piston rods 15o retracting into the respective double cylinders 9they are disposed within the space limited by the four struts 21 of the stiffening structure 20 of the cylinder assembly 18. The same applies to the first swivel drive carrier 38 and the second swivel drive carrier 41. Thus the head frame 24 can be lowered to the end plates 14 of the linear actuator units 8; and the head structure 2 nowhere projects laterally beyond the contour of the cylinder assembly 18.