Arrangement and procedure for the operating table with overload detection device

Abstract

Operating table for positioning a patient, including - a floor group; - a table top (1) movable with respect to the base assembly for positioning a patient; - at least one hydraulic drive (13) with a piston (17) for controlling the position of the table top (1) relative to the base assembly; - Overload detection device to determine when the operating table is overloaded, • wherein the overload detection means comprises a sensor for detecting one of the parameters of the operating table, which detects a force exerted on the drive (13), wherein the sensor is a hydraulic pressure switch (25) and the detected parameter is a hydraulic differential pressure across the piston (17) of the hydraulic drive (13), and • wherein the overload detection device emits a signal when the detected parameter exceeds a predetermined value due to the weight and / or position of the patient on the table top (1).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an operating table with a movable upper part for supporting a patient during a medical procedure. BACKGROUND OF THE INVENTION

[0002] Operating tables comprise a top for supporting a patient during a medical procedure, and a base assembly arranged underneath. The base assembly typically includes some type of support column upon which the table top is mounted. The top typically consists of a plurality of interconnected top sections, for example, a headrest section, a backrest section, and a legrest section. The top can typically be tilted to various angles relative to the support column. Likewise, the top sections can typically be aligned at variable angles to each other, allowing the patient to be appropriately positioned for the medical procedure.

[0003] In some cases, the upper section can also be moved longitudinally relative to the base assembly. This is particularly advantageous as it allows better access to all parts of the patient's body, for example, when X-rays of various parts of the patient's body are required. This allows the operating table upper section, with the patient on it, to be easily moved between the opposite ends of a C-shaped X-ray image intensifier, where one end of the intensifier is located below the patient and the other end above the patient, without the operating table's support column becoming an obstruction.

[0004] One problem with tilting and / or sliding the top relative to the support column below is that the weight of the patient can cause the operating table to become unstable and tip over. In this context, it is not uncommon for the patient to be positioned near one end of the operating table for a medical procedure. For example, if a patient's legs require splinting, the patient will typically lie supine with their pelvis at one end of the operating table top. In such a position, the risk of the table becoming unstable is potentially high. The risk of the table becoming unstable and tipping over is further increased if the patient is overweight and / or the table is moved or tilted to an extreme position.

[0005] In the past, attempts have been made to minimize the risk of an unstable operating table by educating medical staff about the maximum patient weight the table can safely support and by further training medical staff on how to correctly position a patient on the operating table to minimize the risk of an unstable table.

[0006] US 2010 / 0 132 117 A1 discloses a piece of furniture, e.g., a bed, with an actuator, a control unit, a control element, and a means for detecting whether the piece of furniture is occupied by a person. A strain gauge is used to monitor the relative change in load compared to a reference value.

[0007] The invention is based on the object of providing an operating table that overcomes or improves the above-mentioned problems of the prior art.

[0008] Any discussion of documents, devices, acts, and knowledge in this application specification has been included for the purpose of explaining the context of the invention. It should not be considered an admission that the material forms part of the basis of prior art or common knowledge in the relevant art in Australia or any other country on or before the priority date of the present claims. SUMMARY OF THE INVENTION

[0009] According to a first aspect of the present invention, an operating table for supporting a patient is provided. The operating table comprises: - a floor group, - a table top movable relative to the base group for supporting a patient, - at least one hydraulic drive with a piston for controlling the position of the table top relative to the base assembly and - Overload detection means for determining when the operating table is overloaded, wherein the overload detection means comprises a sensor for detecting one of the parameters of the operating table which detects a force exerted on the drive, wherein the sensor is a hydraulic pressure switch and the detected parameter is a hydraulic differential pressure across the piston of the hydraulic drive, wherein the overload detection means emits a signal when the detected parameter exceeds a predetermined value due to the weight and / or body position of the patient on the operating table.

[0010] The hydraulic actuator has a piston within the actuator cylinder. The piston divides the cylinder into an upper and a lower section. Preferably, the pressure switch comprises a first chamber with a fluid port connected to an upper section of the cylinder via a first hydraulic fluid line, and a second chamber with a fluid port connected to the lower section of the cylinder via a second fluid line.

[0011] The first and second chambers may each have a sealing body capable of moving along the side walls of the chambers. The area between the sealing body of the first chamber and the fluid port of the first chamber defines a first fluid cavity, and the area between the sealing body of the second chamber and the fluid port of the second chamber defines a second fluid cavity.

[0012] An increase or decrease in the hydraulic pressure in the upper section of the cylinder results in a corresponding increase or decrease in the hydraulic pressure in the first fluid cavity. Likewise, an increase or decrease in the hydraulic pressure in the lower section of the cylinder results in a corresponding increase or decrease in the hydraulic pressure in the second fluid cavity. The corresponding increase or decrease in the hydraulic pressure in the first or second fluid cavity acts on the sealing bodies.

[0013] The pressure switch may further comprise a drive arm, one end of which is connected to the sealing body of the first chamber and the other end of which is connected to the sealing body of the second chamber. The drive arm comprises an element that can be positioned to actuate an electrical switch, thereby activating an overload indicator of the overload detection means when the detected parameter exceeds the predetermined value. The signal emitted when the detected parameter exceeds the predetermined value may be an audible or visible signal from the overload indicator.

[0014] The first chamber may further include a spring positioned therein that holds the sealing body of the first chamber and the drive arm in a position where the drive arm is unable to close the electrical switch. The first chamber may additionally include an adjustable spacer disposed between the spring and an end wall of the first chamber to allow adjustment of the holding force of the spring.

[0015] According to an alternative embodiment, the sensor is a pressure transmitter and the measured parameter is the force exerted on the actuator.

[0016] The operating table of the present invention advantageously provides an indication to medical personnel, surgeons, etc., when the table is overloaded and therefore there is a risk that the table will become unstable and tip over.

[0017] It is understood that throughout the application description and claims, the term "operating table" refers to any type of table intended to support a patient during a medical procedure, such as surgical procedures, operations, magnetic resonance imaging (MRI), X-ray images, non-surgical procedures, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further benefits and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention. The preferred embodiments should not be construed as limiting the statements made in the preceding section. The preferred embodiments are described with reference to the following figures. Fig. 1: a side view of an operating table according to an embodiment of the invention, Fig. 2: a hydraulic drive and pressure switch of the operating table according to another embodiment and Fig. 3: a hydraulic drive and pressure switch of the operating table according to yet another embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] With reference to Fig. 1 of the accompanying drawings, an operating table according to the embodiment of the invention is shown. The operating table comprises a table top 1, which is movable relative to the base assembly 3. The table top 1 preferably comprises a plurality of top sections 4, which are connected to one another. Fig. 1, the base assembly 3 comprises a support column 5, one end of which is pivotally connected to a connecting arm 7 of the table top 1 via a connecting pin 9, wherein the connecting pin 9 defines a horizontal transverse pivot axis. The table top 1 can thereby be pivoted relative to the base assembly 3 about the horizontal transverse pivot axis, so that the table top 1 can assume a Trendelenburg position (head down), a reverse Trendelenburg position (head up), and any position in between. In other embodiments (not shown), the base assembly 3 can be designed such that the table top 1 can also be moved in other ways. For example, the table top 1 can be displaced relative to the base assembly 3 and can also be pivoted laterally about a longitudinal axis of the table top 1.The table top 1 is positioned eccentrically with respect to the support column 5, with a first end 8 of the table top 1 being further away from the support column 5 than a second end 10.

[0020] To control the movement of the table top 1 about the horizontal transverse axis, the operating table further comprises at least one drive, also known as a Trendelenburg drive, one end of which is preferably connected to the table top 1 and the opposite end of which is preferably connected to the base assembly 3. The operating table may also comprise other drives (not shown in the drawings) to control the movement of the table top 1 in other directions, for example, lateral pivoting about the longitudinal axis and translational movement relative to the base assembly 3. In the embodiments shown in the drawings, the Trendelenburg drive is designed as a hydraulic drive 13, preferably with a dual function. The hydraulic drive 13 is conventionally designed and comprises a cylinder 15 with fluid therein and a piston 17 and an associated piston rod 18. In Fig. 1, one end 19 of the hydraulic drive 13 is connected to the table top 1, and an opposite end 21 is connected to a mounting arm 23 of the support column 5. The hydraulic drive 13 is arranged below the table top 1 between the connecting pin 9 forming the horizontal transverse pivot axis and the first end 8 of the table top 1. Accordingly, when the table top 1 is in a horizontal position, the hydraulic drive 13 supports the table top 1 and prevents the first and second ends 8, 10 from moving up or down.

[0021] The operating table further comprises an overload detection device for detecting when the table top 1 has reached its load limit. The overload detection device comprises a sensor for detecting a parameter of the operating table. The function of the overload detection device is to emit a signal when the detected parameter exceeds a predetermined value. Fig. In the embodiment shown in Figure 1, the sensor is a hydraulic pressure switch 25 connected to the hydraulic drive 13. The overload detection means further comprises an overload indicator 27 that emits an audible and / or visual signal when the hydraulic pressure switch 25 detects that the hydraulic fluid pressure with the hydraulic drive 13 has reached a selected pressure for activating the pressure switch 25. The 27 may be a siren, voice synthesizer, flashing lights, or a combination thereof. The overload detection means may further comprise a power supply, preferably in the form of a battery 26, electrically connected to the pressure switch 25 and the overload indicator 27. The pressure switch 25 is advantageously set so that the switch 25 is activated when a force of a certain magnitude is exerted on the table top 1.For example, if a patient is positioned at the first end 8 of the table top 1, the patient's weight triggers an increase in the hydraulic fluid pressure in the lower section of the Trendelenburg drive 13. Depending on the size and position of the patient, the force exerted by the patient on the table top 1 may be sufficient to increase the hydraulic fluid pressure in the lower section of the hydraulic drive 13 to a value at which the pressure switch 25 is activated, triggering the overload indicator. The indicator warns medical personnel that the patient's weight cannot be safely supported in the assumed position on the table top 1. However, the overload detection means does not hinder, restrict, or limit the range of movement of the table top 1, even if an overload is detected.

[0022] If the pressure switch 25 is connected to the area of ​​the cylinder 15 where the piston rod 18 is located, the pressure switch 25 can also be activated when the hydraulic fluid pressure in the upper section of the Trendelenburg drive 13, where the piston rod 18 is located, increases to a certain value. For example, if a patient is positioned near the second end 10 of the table top 1, the force exerted by the patient on the table top 1 will move the piston rod 18 away from the cylinder 15, which in turn causes an increase in the hydraulic fluid pressure in the upper section of the Trendelenburg drive 13. The pressure increase may be sufficient to activate the pressure switch 25 and trigger an overload indicator 27 as a warning that a patient of this weight cannot be safely positioned in this position on the table top 1.The hydraulic fluid pressure is thus effectively used as the force exerted by the patient on the table top 1. The exerted force depends on the patient's weight and position. The pressure switch 25 can also be activated when the hydraulic fluid pressure in the Trendelenburg drive 13 decreases to a certain value.

[0023] In the Fig. 2 and Fig. In the embodiments of the invention illustrated in Figure 3, the pressure switch 25 is depicted as a differential pressure switch 28. The differential pressure switch 28 is functionally connected to the hydraulic drive 13.

[0024] In the Fig. 2 and Fig. The drive shown in Figure 3 is preferably the Trendelenburg drive of the operating table. However, the hydraulic drive 13 shown could also be any other drive of the operating table. Since the hydraulic drive 13 preferably has a dual function, hydraulic fluid can be provided on both sides of the piston 17 so that the piston rod 18 can be extended and retracted relative to the cylinder 15 by the hydraulic fluid pressure. Fluid is supplied to the side of the piston 17 with the piston rod 18 (also called the "upper section of the cylinder 15") through a first supply line 29 connected to a hydraulic fluid source. A second supply line 31 connected to the hydraulic fluid source supplies the other side of the piston 17 with hydraulic fluid (also called the "lower section of the piston 15").

[0025] The differential pressure switch 28 comprises a first chamber 33 with a fluid connection 35, which is connected at one end to a first supply line 29, and a second chamber 37 with a fluid connection 39, which is connected at one end to the second supply line 31. The first and second chambers 33, 37 each comprise a sealing body, which is preferably designed as a movable piston 41, 42. An area between the piston 41 of the first chamber 33 and the fluid connection 35 delimits a first fluid cavity 43, in which hydraulic fluid is located. An area between the second piston 42 of the second chamber 37 and the fluid connection 39 delimits a second fluid cavity 45, in which hydraulic fluid is located.

[0026] The differential pressure switch 28 in the Fig. 2 further comprises a fixed drive rod or follower arm 47, one end of which is connected to the first chamber piston 41 and the other end to the chamber piston 42. Opposite end walls of the first and second chambers 33, 37 each have an opening through which the follower arm 47 extends. The fixed follower arm 47 includes a projecting part 49 that can be positioned to actuate an electrical switch 51 to activate the overload indicator 27 (in Fig. 2 not shown). A spring 53 is located in the first chamber 33 to hold the piston 41 of the first chamber and the fixed follower arm 47 in a position in which the projecting part 49 is unable to close the electrical switch 51. An adjustable spacer 57 is arranged between the spring 53 and the end wall of the first chamber 33 so that the holding force of the spring 53 can be adjusted.

[0027] If a force is applied to move the piston rod 18 away from the cylinder 15, for example, due to the position and weight of the patient on the table top 1, the hydraulic fluid pressure in the upper section of the cylinder 15 increases, thereby increasing the fluid pressure in the first fluid cavity 43. The force produced by the increase in fluid pressure then acts on the piston 41 of the first chamber and the follower arm 47 attached to it. At the same time, the pressure in the lower section of the cylinder 15 drops, thereby reducing the fluid pressure in the second fluid cavity 45. By reducing the pressure, less force is exerted on the second chamber piston 42.

[0028] If a force is applied to retract the piston rod 18, the hydraulic pressure in the upper portion of the cylinder 15 decreases, causing a reduction in the fluid pressure in the first fluid cavity 43 and thus exerting less force on the first chamber piston 41. At the same time, the pressure in the lower portion of the cylinder 15 increases, exerting more force on the second piston 42, which force acts on the drive arm 47 attached thereto.

[0029] To actuate the differential pressure switch 28, the protruding portion 49 of the follower arm 47 must be displaced until the electrical switch 51 closes. The force exerted on the follower arm 47 by the first chamber piston 41 minus the force exerted on the drive arm 47 by the second chamber piston must be sufficient to overcome the holding force of the spring 53 on the piston 41 of the first chamber 33 and the attached follower arm 47, so that the follower arm 47 and the protruding portion 49 of the follower arm 47 are moved to close the electrical switch 51. The spring 53 is preferably adjusted so that the holding force is 2000 psi (approximately 13.79 MPa). Therefore, if the differential pressure switch 28 is to be activated, the hydraulic fluid pressure in the upper section of the cylinder 15 minus the fluid pressure in the lower section of the cylinder 15 must be at least more than 2000 psi (13.79 MPa).In other words, the hydraulic fluid pressure of the actuator 13 must be greater than approximately 2000 psi (13.79 MPa). Under normal operating conditions, for example, where the patient and table top are stationary and the table top 1 is substantially directly above the support column 5, the hydraulic fluid pressure in the upper section of the cylinder 15 is approximately 1500 psi (approximately 10.34 MPa). However, if the patient is particularly heavy or is located at one end of the table top 1 and / or the table top 1 has been pushed into certain positions relative to the floor assembly 3, the fluid pressure in the upper section of the cylinder 15 minus the fluid pressure in the lower section of the cylinder 15 can increase to an amount at which the pressure difference, i.e., the hydraulic differential pressure across the piston 17, exceeds approximately 2000 psi, thereby activating the overload indicator 27.

[0030] The overload detection means is preferably in operation at all times, regardless of whether a main operating control of the operating table is switched on or off. The overload detection means does not use any electrical current from the battery 26 until the hydraulic pressure switch is activated and / or an audible warning signal is emitted. Although the Fig. 1 shown overload detection devices only at the points shown in the Fig. 1, it is, however, possible to use further drives and associated overload detection means to monitor movements of the table top 1 in other directions, for example a lateral pivoting about the longitudinal axis of the table top 1.

[0031] In another embodiment of the invention, the differential pressure switch is a pressure transmitter, preferably a differential pressure transmitter, which detects and measures the hydraulic fluid pressure within the actuator 13, preferably in the upper and lower sections of the cylinder 15. In this particular embodiment, the differential pressure transmitter continuously measures the pressure within the actuator 13 and provides an electrical output signal to a microprocessor of a signal processing unit, thereby determining whether the measured differential pressure exceeds a predetermined value. The differential pressure switch of the Fig.3, comprises a first pressure transducer 58 connected to the first supply line 29 and a second pressure transducer 59 connected to the second supply line 31. The first and second pressure transducers 58, 59 measure the pressure within the upper and lower sections of the cylinder 15, with electrical outputs of the pressure transducers 58, 59 being connected to a signal processor 60. The signal processor 60 contains a microprocessor that calculates the resulting voltage by subtracting the output voltage of the second pressure transducer 59 from the output voltage of the first pressure transducer 58. The resulting voltage is compared to predetermined upper and lower limit values. If the resulting voltage lies outside the limit values, an output signal 61 is emitted from the signal processor 60 to trigger the activation of the overload indicator 27.

[0032] Most modern hydraulically operated operating tables have a microprocessor connected to a manually operated actuator for controlling the movements of the table top 1. Instead of a dedicated signal processing unit 60, the pressure transducers 58, 59 can be connected to the operating table's microprocessor. The predetermined value for the differential pressure within the hydraulic drive 13 can thus be programmed into the operating table via the manually operated control means, in the same way as various other operating parameters of the table would normally be set. An advantage of connecting the pressure transducers 58, 59 to the operating table's existing microprocessor is that the pressure values ​​at which an overload signal is to be issued can be set to different values ​​for different positions of the table top 1 relative to the support column 5.

[0033] In another embodiment of the invention, the sensor of the overload detection means may be in the form of a force transducer, wherein the parameter of the operating table detected by the force transducer is applied by force to the drive 13 or to a mounting point of the drive 13. A sensor of this type is particularly suitable for older operating tables that do not use hydraulic drives to move the table top 1. These older operating tables instead have an electromechanical drive in which an electric motor uses a lead screw to move the table top 1. A force transducer, for example a voltmeter, may be mounted on one end of the drive 13 so that the force exerted on the drive by the weight and / or position of the patient on the table top 1 can be measured.

[0034] The operating table advantageously emits an audible or visible warning signal when the overload detection device detects that a predetermined load limit has been reached. This provides early warning to medical personnel that a patient weighs too much to be safely positioned in a specific position on the table top.

[0035] Since the present invention can be implemented in various embodiments without departing from the essential characteristics of the invention, it is understood that the above-described embodiments should not be construed as limiting the present invention, but should be interpreted broadly. Various modifications and equivalents are intended to be included within the spirit and scope of the invention. For example, the drive may be hydraulic, pneumatic, electric, or mechanical, respectively.

Claims

[1] Operating table for the positioning of a patient, comprising - a floor group; - a table top (1) movable relative to the base assembly for supporting a patient; - at least one hydraulic drive (13) with a piston (17) for controlling the position of the table top (1) relative to the base group; - Overload detection device to determine when the operating table is overloaded, • wherein the overload detection means comprises a sensor for detecting one of the parameters of the operating table, which detects a force exerted on the drive (13), wherein the sensor is a hydraulic pressure switch (25) and the detected parameter is a hydraulic differential pressure across the piston (17) of the hydraulic drive (13), and • wherein the overload detection means emits a signal when the detected parameter exceeds a predetermined value due to the weight and / or position of the patient on the table top (1). [2] Operating table according to claim 1, wherein the piston (17) is arranged within a cylinder (15) of the hydraulic drive (13), wherein the piston (17) divides the cylinder (15) into an upper and a lower section, and wherein the pressure switch (25) contains: - a first chamber (33) with a fluid connection connected to an upper portion of the cylinder (15) via a first hydraulic fluid line, and - a second chamber (37) with a fluid connection connected to the lower portion of the cylinder (15) via a second fluid line. [3] Operating table according to claim 2, wherein the first and second chambers (33, 37) each have a sealing body, wherein a region between the sealing body of the first chamber (33) and the fluid connection of the first chamber (33) defines a first fluid cavity and a region between the sealing body of the second chamber (37) and the fluid connection of the second chamber (37) defines a second fluid cavity. [4] Operating table according to claim 3, wherein an increase in the hydraulic pressure in the upper section of the cylinder (15) results in a corresponding increase in the hydraulic pressure in the first fluid cavity (33) or a decrease in the hydraulic pressure in the upper section of the cylinder (15) results in a corresponding decrease in the hydraulic pressure. [5] Operating table according to claim 3 or 4, wherein an increase in the hydraulic pressure in the lower section of the cylinder (15) results in a corresponding increase in the hydraulic pressure in the second fluid cavity (37) or a decrease in the hydraulic pressure in the lower section of the cylinder (15) results in a corresponding decrease in the hydraulic pressure. [6] Operating table according to claim 4 or 5, wherein the corresponding increase or decrease in the hydraulic pressure in the first fluid cavity (33) acts on a sealing body of the first fluid cavity (33) and the corresponding increase or decrease in the hydraulic pressure in the second fluid cavity (37) acts on a sealing body of the second fluid cavity (37). [7] Operating table according to one of claims 3 to 6, wherein the pressure switch (25) further comprises a drive arm (47) having one end connected to the sealing body of the first chamber (33) and the other end connected to the sealing body of the second chamber (37). [8] Operating table according to claim 7, wherein the drive arm (47) comprises an element that can be positioned to actuate an electrical switch to activate an overload indicator (27) of an overload detection means when the detected parameter exceeds the predetermined value. [9] Operating table according to claim 8, wherein the signal emitted by the overload indicator (27) when the detected parameter exceeds the predetermined value is an audible or visible signal. [10] Operating table according to claim 8 or 9, wherein the first chamber (33) further comprises a spring (53) positioned therein, which holds the sealing body of the first chamber (33) and the drive arm (47) in a position in which it is not possible for the drive arm (47) to close the electrical switch. [11] Operating table according to claim 10, wherein the first chamber (33) further comprises an adjustable spacer (57) arranged between the spring (53) and an end wall of the first chamber (33) to enable adjustment of the holding force of the spring (53). [12] Operating table according to claim 11, wherein the drive arm (47) can close the electrical switch when the hydraulic pressure in the first fluid cavity minus the hydraulic pressure in the second fluid cavity is greater than the holding force of the spring (53). [13] The operating table of claim 12, wherein the holding force of the spring (53) is approximately 2000 psi (13.79 MPa). [14] Operating table according to claim 1, wherein the pressure switch (25) further comprises a first pressure sensor (58) and a second pressure sensor (59) for detecting and measuring the hydraulic pressure difference across the piston (17) of the hydraulic drive (13).

Images