PATIENT LIFTERS AND METHOD FOR CONTROLLING A PATIENT LIFTERS

Abstract

The invention relates to a patient lift with a frame on which a mast (3) is mounted, on which a support arm (5) is pivotably arranged. The angle of the support arm relative to the mast (3) is adjustable by means of an electric linear drive (7), whereby a patient platform (6) arranged on the support arm (5) moves along a predetermined trajectory. The patient lift is characterized in that at least one further electric drive (8) is provided, by means of which the patient platform can be moved along a further trajectory that differs from the predetermined trajectory. The invention further relates to a method for controlling a patient lift.

Description

[0001] The invention relates to a patient hoist with a frame on which a mast is mounted. A support arm is pivotably mounted on the mast, the angle of which can be adjusted relative to the mast via an electric motor-driven linear drive, whereby a patient support arranged on the support arm moves along a predetermined trajectory. The invention further relates to a method for controlling a patient hoist.

[0002] Patient hoists are used in healthcare settings and assist in lifting, repositioning, or transporting patients. They can also be used as a standing aid for patients, for which they are typically supplemented with a knee support. A simple and functional design for patient hoists has proven to be established: a mast mounted on a frame, often a chassis, with a pivoting support arm mounted at the upper end. Such a design is shown, for example, in the document DE 199 50 689 A1, where the support arm can be pivoted relative to the mast using an electric linear drive to lift the patient or assist them in standing.

[0003] Patient hoists are known whose geometry is adapted to one or the other of the two functions - lifting or transporting the patient as opposed to assisting the patient to stand up. Furthermore, the document DE 20 2017 003 987 U1 discloses a patient hoist whose mast is telescopic and can be used in two different operating positions. The operating position, in which the mast is shorter, is advantageous for functioning as a standing aid, whereas the second operating position, in which the mast is longer, is advantageous for lifting or transporting the patient. The mast has two telescopic sections that can be moved into one another and secured in one or the other operating position, for example, by inserting a bolt into corresponding holes.The change between the two operating positions takes place before the patient hoist is used in one way or another and involves a corresponding amount of effort for the nursing staff.

[0004] It is an object of the present invention to provide a patient hoist of the type mentioned above which can be used flexibly for various functions such as lifting or repositioning as well as as a standing aid, wherein a change of function should be possible with as little effort as possible.

[0005] This object is achieved by a patient hoist and a method for controlling a patient hoist having the features of the respective independent claim. Advantageous embodiments and further developments are the subject of the dependent claims.

[0006] A patient hoist according to the invention of the type mentioned at the outset is characterized in that at least one further electric motor drive is provided, via which the patient support can be moved along a further trajectory that differs from the predetermined trajectory. Thus, according to the invention, at least one further electric motor drive is used to give the movement of the free end of the support arm a further degree of freedom. By using the electric motor drive, the additional movement can be easily implemented, which reduces the effort required by the nursing staff. Furthermore, this additional movement along the further trajectory, if necessary combined with a movement along the predetermined trajectory, can also be performed while the patient hoist is in use, which enables more flexible adaptation of the movement sequence depending on the situation.

[0007] In an advantageous embodiment of the patient hoist, the mast is pivotable relative to the frame and can be pivoted by means of at least one additional electric motor drive. Alternatively, the mast can be constructed in two parts, with a lower section being firmly attached to the frame at a predetermined angle and an upper section pivotable relative to the lower section by means of at least one additional electric motor drive.

[0008] It is also possible to pivot the lower section onto the frame and pivot it using at least one additional electric motor drive. The upper section is then pivotably mounted on the lower section and is positively guided in its alignment relative to the frame via a parallel or trapezoidal guide.

[0009] In a further advantageous embodiment of the patient lift, the support arm is designed in two parts, wherein a first section is fastened to the mast and a second section can be pivoted in a vertical plane relative to the first section by means of at least one further electric motor drive.

[0010] In a further advantageous embodiment, the mast is designed to be telescopic and its length can be adjusted via at least one further electric motor drive.

[0011] In a further advantageous embodiment, the support arm is designed to be telescopic and its length can be adjusted via at least one further electric motor drive.

[0012] In all five cases mentioned, the additional electric motor drive enables a change in the geometry of the patient hoist's supporting elements—i.e., the frame, mast, and support arm—relative to each other. As a result, when the additional electric motor drive is activated, the free end of the support arm moves along a trajectory that cannot be achieved by changing the pivot angle of the support arm relative to the mast. Furthermore, a changed setting of the additional electric motor drive also changes the trajectory along which the free end of the support arm moves when it is pivoted relative to the mast.

[0013] By presetting one of the two drives, operating the other drive results in a movement of the free end of the support arm, which is typically located on a patient support device such as a handle or a sling or belt arrangement, that is suitable for the intended application of the patient lift. Alternatively, a coordinated simultaneous operation of both drives is conceivable to achieve a defined and optimized patient support trajectory.

[0014] In an advantageous embodiment, a linear drive can be used as an additional electric motor drive. Alternatively, a rotary actuator, possibly with an additional lever mechanism, can be used.

[0015] A chassis is advantageously used as the frame to allow for spatial flexibility in the patient hoist and also for transport purposes. Furthermore, a control unit is provided, preferably located on the mast, which controls the electric linear drive and the additional electric drive and supplies them with operating power. The control unit is further preferably coupled to or equipped with a power supply unit, e.g., a rechargeable battery.

[0016] A method according to the invention is used to control a patient lift having a support arm with a patient support, wherein the patient support is movable along a predetermined trajectory using an electric motor-driven linear drive and along a further trajectory using a further electric motor drive. The method comprises the following steps: A position of the patient support and / or a force acting on the patient support is determined. The electric motor-driven linear drive and / or the further electric motor drive are then controlled depending on the determined position and / or force.

[0017] According to the invention, when controlling the two drives, i.e., the electric linear drive and the additional drive, measured data of the position of the patient support and / or the force acting on it are taken into account. This allows a desired position or force profile to be achieved during the movement of the patient lift.

[0018] In particular, to control the patient hoist, a predefined trajectory, consisting of movements along the predetermined trajectory and / or the further trajectory, can be advantageously followed based on the determined position and / or taking into account the applied force. In this way, ergonomically favorable movement sequences can be implemented, particularly for assisting the patient to stand up.

[0019] Additionally, the specified trajectory can be followed in such a way that a specified maximum force curve is not exceeded. This supports the patient's natural standing movement while simultaneously challenging and training the patient.

[0020] The invention is explained in more detail below using exemplary embodiments and figures. The figures show: Fig. 1 shows a first embodiment of a patient lift in a schematic side view; Fig. 2 shows a second embodiment of a patient lift in a schematic side view; Fig. 3 shows a third embodiment of a patient lift in a schematic side view; Fig. 4 shows a fourth embodiment of a patient lift in a schematic side view; Fig. 5 shows a fifth embodiment of a patient lift in a schematic side view; and Fig. 6 shows a sixth embodiment of a patient lift in a schematic side view.

[0021] The Figuren 1-6 Each shows an embodiment of a patient hoist according to the application in a schematic side view. In all figures, identical reference numerals identify identical or similarly functioning elements. In the following, references such as "right," "left," "top," and "bottom" refer to the figures, with the references "top," "bottom," as well as "vertical" and "horizontal" corresponding to the usual spatial directions. The references "front" and "back" indicate the directions toward the patient ("front") and the opposite direction ("back"), respectively.

[0022] The patient lift according to Fig. 1 has a frame designed as a chassis 1, which comprises two V-shaped or U-shaped horizontal arms pointing forward towards the patient, each provided with a wheel at the front and a wheel at the rear. The wheels are equipped with brakes, which are shown in the schematic drawing of the Fig. 1 are not shown. On the rear side of the patient hoist facing away from the patient (in the Fig. 1 On the chassis 1 (left), a mast base 2 is arranged, which supports an upwardly projecting mast 3. A handle 4 is mounted on the mast 3, by which the patient hoist can be pushed or pulled and positioned by the nursing staff. Furthermore, a control unit of the patient hoist is usually mounted on the mast 3; this control unit is not shown in the figures of this application for the sake of simplicity. The control unit is used to control the patient hoist and usually also includes its power supply in the form of rechargeable batteries. The functioning of the control unit is explained in more detail below in connection with the method according to the invention.

[0023] In the area of ​​the upper end of the mast 3, a pivotable support arm 5 is arranged, which projects forward over the chassis 1 in the direction of the patient.

[0024] The support arm 5 is angled in the example shown. Other geometries are also possible. The support arm 5 is pivotally connected to the mast 3 at a joint, from which Fig. 1 a pivot axis 31 is visible.

[0025] At the front, free end of the support arm 5, there is a patient support 6, which is only indicated in the figures shown here. Depending on the use of the patient hoist, the patient support 6 can include grab handles, bars, and / or slings or straps.

[0026] The pivoting position of the support arm 5 relative to the mast 3 can be adjusted by an electric motor-driven linear drive 7, allowing the patient support 6 to be raised or lowered along a circular arc. For this purpose, the electric motor-driven linear drive 7 is pivotally connected to both the mast 3 and the support arm 5. A bracket 32 ​​is arranged on the mast 3, which provides a bearing 33 for the electric motor-driven linear drive 7. Similarly, a bearing 51 is provided on the support arm 5 for an opposite end of the electric motor-driven linear drive 7. At the ends of the electric motor-driven linear drive 7, for example, bearing eyes are formed, through which an axis of the bearing 33, 51 is guided.

[0027] According to the registration, the patient lifter has Fig. 1 a further electromotive drive 8, with which an electromotive adjustment of the patient support 6 takes place along a different trajectory than when the electromotive linear drive 7 is actuated.

[0028] In the embodiment of the Fig. 1 The mast 3 is not mounted at a fixed angle in the mast base 2, but is pivoted about a joint on the chassis 1. The plane in which this pivoting takes place is the vertical plane spanned by the mast 3 and the support arm 5. The joint is in the Fig. 1 a pivot axis 21 is shown.

[0029] The additional electric motor drive 8 is also, for example, a linear drive arranged between the mast base 2 or a bracket 22 attached thereto and the bracket 32 ​​on the mast 3. In a similar manner to the electric motor linear drive 7, the additional electric motor drive 8 is attached to the respective bracket 22 or 32 in bearings 23 and 34, respectively. Advantageously, in the example shown, the same bracket 32 ​​is used for the additional electric motor linear drive 8 to which the electric motor linear drive 7 is also mounted. In alternative embodiments, separate brackets can also be provided for coupling the mast 3 to the two drives 7, 8.

[0030] The actuation of the further electric motor drive 8 pivots the mast 3 around the pivot axis 21, as indicated by a movement arrow 9 in the Fig. 1 is indicated. The additional degree of freedom thus added allows the inclination of mast 3 to be optimally adjusted for the intended use of the patient hoist. For example, mast 3 can be advantageously positioned at a steeper angle for lifting or repositioning a patient, and tilted further back away from the patient for use as a stand-up aid. For use as a stand-up aid, a knee or shin support surface (not shown here) can optionally be mounted to chassis 1 or mast 3.

[0031] The additional electric motor drive 8 can also be actuated during use of the patient hoist, for example in order to be able to move the patient support 6 primarily forwards and backwards when used as a standing aid and not primarily up and down, as is the case when using the electric motor linear drive 7.

[0032] The additional electric motor drive 8 is only subjected to pressure during operation, which allows for a simpler design if the additional electric motor drive 8 is designed as a linear drive. A further advantage of a drive that is only subjected to pressure is that it can be designed in such a way that no tensile forces can be applied at all. This minimizes the risk of trapping something or someone when encountering an obstacle in the direction of pull.

[0033] Furthermore, it can be provided that the drives 7, 8 are controlled in a coordinated manner so that the patient support 6 follows a desired trajectory. In particular, the standing-up process can be optimally supported in this way.

[0034] Fig. 2 shows a opposite Fig. 1 modified embodiment. Regarding the basic structure, in connection with all embodiments described below, reference is made to the design for Fig. 1 In the following, Fig. 2 and also in the other Fig. 3-5 In each case, the differences to the first embodiment are essentially discussed.

[0035] In the embodiment of the Fig. 2 The mast 3 is divided into two sections 3a, 3b, which are pivotally connected to each other about a pivot axis 21. The additional electric motor drive 8, also designed here as a linear drive, is coupled to each of the sections 3a, 3b. This is achieved via a respective bracket 35, 37, which is arranged on the respective section 3a or 3b and to which the additional electric motor drive 8 is connected via a respective bearing 36, 38.

[0036] As in the example of the Fig. 1 The upper end of the mast 3 performs a pivoting movement about the pivot axis 21 when the electric motor drive 8 is actuated. The resulting movement of the upper end of the mast 3 is again symbolized by a movement arrow 9. The movement of the patient support 6 when the further electric motor drive 8 is actuated differs from that of the first embodiment in that the distance between the pivot axis 21 and the upper end of the mast 3 in the embodiment of the Fig. 2 is shorter than that of the Fig. 1 and secondly, in that in the first embodiment, an actuation of the further electric motor drive 8 has no influence on the relative position of the two connection points in the bearings 33 and 51 of the electric motor linear drive 7. This is the case in the embodiment of the Fig. 2 different, since actuation of the additional electric motor drive 8 changes the position of the upper bearing 51 of the electric motor linear drive 7 relative to the lower bearing 33. With coordinated control of both drives 7, 8, a desired, defined trajectory for the patient admission 6 can also be implemented in this example.

[0037] In the embodiment of the Fig. 3 is like the example of Fig. 1 A one-piece mast 3 is provided, and the support arm 5 has two sections 5a, 5b that can be pivoted relative to one another about a pivot axis 52. A bracket 53, 55 is arranged on each of the sections 5a, 5b of the support arm 5, to which the additional electric motor drive is fastened in bearings 54, 56. Actuation of the additional electric motor drive 8 pivots section 5b of the support arm 5 relative to section 5a. The trajectory of the patient support 6 resulting from actuation of the additional electric motor drive 8 is influenced by the geometry of sections 5a, 5b of the support arm 5.

[0038] In the illustrated case, section 5b of the support arm 5 is straight, and section 5a is angled upwards. As with the previous embodiments, an optimized positioning and movement trajectory for the patient support 6 for the respective application can be achieved by appropriately presetting one of the two drives 7, 8 and actuating the other drive 7, 8, or by synchronously actuating both drives 7, 8.

[0039] The examples of the Fig. 4 and 5 each show the use of a further electric motor drive 8 to either move the mast 3 ( Fig. 4 ) or the support arm 5 ( Fig. 5 ) to telescope.

[0040] In the example of Fig. 4 The mast 3 is divided into two sections 3a, 3b, which are mounted so that they can be displaced relative to one another. For example, as in the example shown, section 3b is designed with a smaller profile diameter so that it can retract into section 3a. Each of the sections 3a, 3b is in turn provided with a tab 35, 37, to which the further electric motor drive 8 is mounted in bearings 36, 38. Since the two sections 3a, 3b perform a linear movement, pivoting in the bearings 36, 38 is not necessary during operation. However, they simplify installation compared to a rigid connection and enable tolerance compensation.

[0041] In the example of Fig. 5 The support arm 5 is divided into two sections 5a, 5b, whereby one of the sections, specifically the front section 5b, is smaller in cross-section than section 5a, so that section 5b can retract into section 5a. The further electric motor drive 8 is connected to sections 5a, 5b in a comparable manner via brackets 53, 55, with a connection to the further electric motor drive 8 being made via bearings 54, 56.

[0042] In both embodiments, the section 3b in the section 3a or the section 5b in the section 5a can be guided, for example, via plain bearings.

[0043] As with the previous embodiments, the linear displacement here allows for a further degree of freedom in the movement of the patient support 6. For example, one of the two drives 7, 8 is preset so that actuation of the other drive 7, 8 results in a movement of the patient support 6 suitable for the intended use of the patient lift. Alternatively, a coordinated simultaneous actuation of both drives 7, 8 is conceivable in order to traverse a defined and optimized trajectory of the patient support 6.

[0044] The embodiment of the Fig. 6 shows a kind of combination and further development of the embodiments of the Figuren 1 and 2 .

[0045] As in the example of Fig. 2 The mast 3 is divided into two sections 3a, 3b. In contrast to the Fig. 2 and comparable with the example of Fig. 1 The mast 3, with its lower section 3a, is pivotably mounted in the mast base 2 about a pivot axis 21. This pivoting is driven by the additional electric motor drive 8.

[0046] The upper section 3b of the mast 3 is then mounted on the lower section 3a in a pivot axis 24. At the lower end of the upper section 3a, a bracket 37 is arranged, which is coupled to a bracket 22 on the mast base 2 via a parallel guide rod 26. The parallel guide rod 26 is mounted in bearings 39 and 25 on the brackets 37 and 22, respectively. Due to the parallel guide thus formed, the upper section 3b of the mast 3 moves back and forth in a circular path when the additional electric motor drive 8 is actuated (see movement arrow 9) without changing its orientation. The effect of the pivoting of the lower section 3a of the mast 3 by means of the additional electric motor drive 8 thus has only a minimal impact on the lifting height of the support arm 5. This is mounted by an electric motor linear drive 7 so as to be pivotable about a pivot axis 31 relative to the upper section 3b of the mast 3.

[0047] The parallel guide rod 26 can alternatively also be mounted on the front side of the mast 3 (ie in the Fig. 6 to the right of section 3a). Instead of the parallel guide rod 26, other power transmission means can also be used for parallel guidance, e.g., a pull chain. Furthermore, instead of a pure parallel guide, a slightly trapezoidal guide can also be provided, whereby the effect of the pivoting of the lower section 3a of the mast 3 on the lifting height of the support arm 5 can be further minimized.

[0048] As already mentioned, a control unit is available to control the patient hoist, for example mounted on the mast 3 or on one of the two drives, i.e. on the electromotive linear drive 7 or the further electromotive drive 8.

[0049] In particular, the control unit is configured to follow a predetermined trajectory for patient admission 6, which is stored, for example, in the control unit.

[0050] Due to its design, each of the two drives is associated with a specific trajectory for patient pickup 6. This trajectory, which results from the geometry of the patient hoist and the installation situation of the respective drive, generally does not represent the physiologically best and desired movement sequence for a specific action of the patient hoist.

[0051] To follow a given trajectory of a desired motion sequence, simultaneous, correlated control of the drives, possibly at different speeds and / or directions, is required. Accordingly, the control unit is preferably configured to control both drives at a continuously variable speed. This is possible, for example, via pulse-width modulation (PWM) control of the drive motors. The modulation frequency is preferably high enough to result in continuous operation of the drives. However, it is also conceivable to select a frequency low enough that the drive moves in (preferably small) discrete steps.

[0052] To enable the two drives to move in any direction, the control unit has a way to reverse the direction of the drives. This can be achieved using a polarity reversal switch with relays. However, the drives are advantageously powered via a bridge circuit with semiconductor switches—particularly an H-bridge arrangement—which allows both pulse width modulation and polarity reversal to be implemented.

[0053] In order to be able to follow a desired, predefined trajectory as precisely as possible and independently of the load situation, devices for direct or indirect position detection of the patient support 6 are preferably provided. Such position detection devices can be, for example, angle sensors positioned on joints of the patient hoist, e.g., the bearings 33, 34, 36, 38, 39. Acceleration sensors, which measure an angle relative to the normal vector of the acceleration due to gravity, or displacement sensors, which detect the position of one of the drives, can also be used for position detection. It is conceivable to arrange the displacement sensors directly in the drives or even outside the drives.

[0054] The sensors can measure absolute positions or output incremental values. In the latter case, an absolute position is calculated based on a known reference position, which is detected, for example, by limit switches.

[0055] Potentiometers or Hall sensors, for example, can serve as position sensors. Optical position sensors can also be used.

[0056] A particularly advantageous design of a position sensor, which can be implemented on a drive with little additional effort, is based on the measurement of induction counter-voltage pulses that arise during the commutating of the drive motors and can be detected. The detected pulses allow the motor's speed to be measured and thus an incremental position determination. This method is also known as "ripple count" or back EMF (electromotive force) measurement.

[0057] Typically, the sensors do not directly detect the position of the patient support 6, but rather a value correlated with it. It is conceivable to convert the values ​​detected by the various sensors into an absolute position of the patient support 6 using conversion tables and / or conversion functions. In this case, the trajectory to be followed for the position of the patient support 6 can also be specified in absolute values.

[0058] Alternatively, it is conceivable that a desired trajectory for patient admission 6 is converted in advance to the correlating sensor values ​​and stored in this form in the control unit. When traversing the trajectory, a control loop whose output controls the drives can then work directly with the setpoints for the various sensors. This reduces the additional computational effort within the control unit, which would otherwise have to be performed in real time.

[0059] Trajectories are preferably followed in a controlled manner, i.e. with feedback using measured values ​​from which the current position of the patient recording can be derived. Alternatively, it is also conceivable to follow a trajectory in a controlled manner by controlling motors with specific PWM values ​​for specific times. In order to prevent or minimize load dependency even in the case of only controlled, non-regulated trajectory follow-up, the load on the motors can be used to correct the specified times. Depending on the load, the nominally specified times are extended or shortened by a specific, also predetermined factor. The motor load is determined by sensors, which can be based, for example, on a measurement of the motor current and / or a speed at a specific motor current.Additional sensors, with which forces on the patient support 6 can be determined directly or indirectly, can also be used to adjust the times during such a time-controlled trajectory movement.

[0060] In addition to following the trajectory, a specification for the maximum force can be maintained during the trajectory. This, for example, encourages the patient to stand up naturally, as they must generate part of the strength themselves, and the patient hoist only provides support. The force control can also be time-dependent, so that the support increases over time and is gradually increased. This prevents patients who are unable to provide the required strength, or not to the desired extent, from receiving more support after a certain period of time, allowing them to perform the planned movement sequence.

[0061] The maximum force that can be applied by the patient lift can vary for different directions of movement of the patient; the maximum force can therefore be specified point by point or section by section along the trajectory, possibly in a multidimensional manner.

[0062] In order to limit the force exerted by the patient lift, it is measured when the drives are activated and compared with the maximum force.

[0063] To measure the force, sensors can be arranged inside or outside each drive, or they can be arranged in or on the frame of the patient hoist, particularly in the area of ​​the joints. Strain gauges or spring elements with spring travel detection, for example, can be used as force sensors. Measurements using piezo sensors are also possible. Furthermore, motor current measurements or speed recording can be carried out with a specified current applied to the motor, from which the acting forces can be indirectly deduced. Furthermore, a voltage induced by the motor can be measured, for example, during the blanking times of the pulse width modulation. This can also be used to determine the load on the drive's motor and thus the force it generates.

[0064] In order to reduce the maximum force on the drive, the previously mentioned pulse width modulation can be used and / or the operating voltage of the drives can be varied. Bezugszeichenliste

[0065] 1Chassis 2Mast base 21,24Pivot axis 22Lubricant 23,25Bearing 26Parallel guide 3Mast 3a, bSection of the mast 31Pivot axis 32, 35, 37Tab 33, 34, 36, 38, 39Bearing 4Handle 5Support arm 5a, bSection of the support arm 51Bearing 52Swivel axis 53.55Label 54.56Bearing 6Patient admission 7Electric linear drive 8additional electric motor drive 9Movement arrow

Claims

1. Patient lift with a frame on which a mast (3) is mounted, on which a support arm (5) is pivotably arranged, which is adjustable in its angle relative to the mast (3) via an electromotive linear drive (7), whereby a patient support (6) arranged on the support arm (5) moves along a predetermined trajectory, characterized in that at least one further electromotor drive (8) is present, via which the patient support can be moved along a further trajectory which differs from the predetermined trajectory.

2. Patient lift according to claim 1, wherein the mast (3) is arranged pivotably relative to the frame and can be pivoted by means of the at least one further electric motor drive (8).

3. Patient lift according to claim 1 or 2, wherein the mast (3) is formed in two parts and has a lower section (3a) and an upper section (3b).

4. Patient lift according to claim 3, wherein the lower section (3a) is fixedly attached to the frame at a predetermined angle and the upper section (3b) can be pivoted relative to the lower section (3a) by means of the at least one further electric motor drive (8).

5. Patient lift according to claim 3, wherein the lower section (3a) is pivotally attached to the frame and can be pivoted by means of the at least one further electric motor drive (8), wherein the upper section (3b) is pivotally mounted on the lower section (3a) and is positively guided in its alignment relative to the frame via a parallel or trapezoidal guide.

6. Patient lift according to one of claims 1 to 5, in which the support arm (5) is formed in two parts, wherein a first section (5a) is fastened to the mast (3) and a second section (5b) can be pivoted in a vertical plane relative to the first section (5b) by means of the at least one further electric motor drive (8).

7. Patient lift according to one of claims 1 to 6, in which the mast (3) is designed to be telescopic and is adjustable in its length via the at least one further electric motor drive (8).

8. Patient lift according to one of claims 1 to 7, in which the support arm (5) is designed to be telescopic and is adjustable in its length via the at least one further electric motor drive (8).

9. Patient lift according to one of claims 1 to 8, wherein the at least one further electromotive drive (8) is a linear drive.

10. Patient lift according to one of claims 1 to 9, wherein the frame is a chassis (1).

11. Patient lift according to one of claims 1 to 10, comprising a control unit for controlling the electromotive linear drive (7) and the at least one further electromotive drive (8).

12. Patient lift according to claim 11, wherein the control unit is configured to operate the electromotive linear drive (7) and the at least one further electromotive drive (8) simultaneously.

13. Patient lift according to claim 11 or 12, wherein the control unit comprises a rechargeable battery for supplying power to the electromotive linear drive (7) and the at least one further electromotive drive (8).

14. Method for controlling a patient lift having a support arm (5) with a patient support (6), wherein the patient support (6) is movable along a predetermined trajectory by means of an electromotive linear drive (7) and along a further trajectory by means of a further electromotive drive (8), comprising the following steps: - determining a position of the patient support (6) and / or a force acting on the patient support (6), and - controlling the electromotive linear drive (7) and / or the further electromotive drive (8) as a function of the determined position and / or force.

15. Method according to claim 14, wherein, for controlling the patient lift, a predetermined trajectory, which is composed of movements along the predetermined trajectory and / or the further trajectory, is followed based on the determined position and / or taking into account the applied force.

16. Method according to claim 15, wherein, for controlling the patient lift, the predetermined trajectory is followed in such a way that a predetermined maximum force curve is not exceeded.