Patent Description:
At a care facility, a need to weigh the patient often occurs. Patient handling apparatuses such as lifts, also referred to as patient hoists, are commonly used to raise, lower and transfer patients who are disabled or who otherwise have mobility problems. Two common types of patient lifts are stanchion-mounted lifts, also known as floor lifts, and ceiling lifts. Floor lifts often have a hoist assembly, which may be disposed at the upper end of a stanchion. The stanchion has a wheeled base, which allows the lift to be moved along the ground to different locations. In order to enable weighing of immobilized patents, patient handling apparatuses may be equipped with a scale. Thus, a patient may be weighed while being suspended from the patient handling apparatus.

Such patient handling apparatus often implements a sub frame arranged inside the main frame of the patient handling apparatus which carries the load of the patient. The patient is weighed by means of a load sensor mounted to the sub frame.

Patient handling apparatus implementing the aforementioned sub frame are associated with substantial drawbacks.

Firstly, it requires the center of gravity of the patient to be inside the area formed by the sub frame. Thus, the sub frame often has to be relatively large, which increases the overall size of the patient handling apparatus, which may be an issue in a care unit where space is often scarce.

Secondly, the process of balancing and calibrating the weighing system is cumbersome and time consuming.

An example of a patient handling apparatus may be seen in <CIT>.

In the light of the above, there is a need for a patient handling apparatus, which is associated with a more compact patient handling apparatus, which is easier to balance.

According to one aspect, a patient handling apparatus is provided. The patient handling apparatus comprises a base with a frame and a patient support device.

The patient handling apparatus further comprises a weighing arrangement for weighing a patient supported by the patient support device. The weighing arrangement comprises a sub frame and a plurality of load sensors. The sub frame is arranged on the load sensors. The load sensors define a weighing area.

The patient support device is mounted to the frame such that a central point of a seat support portion of the patient support device is positioned outside the weighing area in at least one position of the patient support device.

According to an aspect, a patient handling apparatus is provided. The patient handling apparatus comprises a base with a frame and a patient support device.

The patient handling apparatus further comprises a weighing arrangement for weighing a patient supported by the patient support device. The weighing arrangement comprises a sub frame and a plurality of load sensors, said sub frame being arranged on the load sensors. The load sensors define a weighing area.

The patient support device is mounted to the frame at a mounting point such that said mounting point is positioned outside the weighing area in at least one position of the patient support device.

According to an aspect, a method for balancing a weighing arrangement of a patient handling is provided. The patient handling apparatus comprises a base with a frame and a patient support device. The weighing arrangement comprises a sub frame and a plurality of load sensors.

The method comprises obtaining sensor signals from said load sensors and adjusting adjustable fixating means to adjust the fixation of the load sensors based on said sensor signals.

Further objects and features of the present invention will appear from the following detailed description of embodiments of the invention.

The invention will be described with reference to the accompanying drawings, in which:.

<FIG> shows a patient handling apparatus <NUM>. The patient handling apparatus <NUM> comprises a base <NUM> with a frame <NUM>. The base <NUM> may be movable relative the ground. The base <NUM> may be provided with wheels <NUM>, <NUM> adapted to allow movement of the base, i.e. the patient handling apparatus <NUM>, relative the ground. The patient handling apparatus <NUM> further comprises a patient support device <NUM>.

The patient handling apparatus <NUM> comprises a patient support device <NUM>. The patient support device <NUM> is adapted to support a patient, i.e. support the weight of said patient.

In one embodiment, the patient support device <NUM> is movable relative to the base <NUM>. The patient support device <NUM> is thus movably mounted to the frame <NUM>. The patient support device <NUM> may for example be movable between an upright position and an inclined position. In the inclined position, patient support device <NUM> is inclined backwards or forwards in the inclined position relative to the upright position by means of a guiding arrangement <NUM>.

An upright position may herein be defined as a position wherein the patient supported by the patient support device <NUM> is in an upright position. Accordingly, the spline of the patient extends substantially in a vertical direction.

An inclined position may herein be defined as a position wherein the patient supported by the patient support device <NUM> is an inclined position, i.e. an inclined position relative the upright position. The inclined position is thus a position wherein the patient is tilted, i.e. the spline of the patient is tilted, relative a vertical axis of the patient handling apparatus.

In one embodiment, the patient support device <NUM> may be movable between a raised position and a lowered position. Thus, the patient support device <NUM> may be movable along a vertical direction.

In one embodiment, the patient support device <NUM> may comprise a seat support portion <NUM>. The seat support portion <NUM> is adapted to support the rear of a patient supported by the patient support device <NUM>.

In one embodiment, the patient support device <NUM> may further comprise a back support portion <NUM>. The back support portion <NUM> is adapted to support the back of a patient when the patient is supported by the patient support device <NUM>.

In one embodiment, the patient support device <NUM> may be in the form of a chair support. The patient support device <NUM> is thus adapted to support a seated patient. Accordingly, the back support portion <NUM> and the seat support portion <NUM> may be substantially orthogonal to each other. In one embodiment, the patient support device <NUM> may further comprise a calf supporting section pivotally mounted to the seat support portion <NUM>. Said calf supporting section is adapted to support the calves of a patient supported by the patient support device <NUM>.

Turning to <FIG> and <FIG>, the patient handling apparatus comprises a weighing arrangement <NUM> for weighing a patient supported by the patient support device <NUM>. Notably, supported herein may refer to any type of supporting of the patient. The type of support provided by the patient support device <NUM> may differ based on the patient's posture and position as well as the type of patient support device <NUM>. For example, the patient may be supported by the patient support device <NUM> by being suspended from the patient support device <NUM> or the patient support device <NUM> constituting a seating surface for a patient in a seated position.

The weighing arrangement comprises a sub frame <NUM> and a plurality of load sensors <NUM>, <NUM>, <NUM>. The sub frame <NUM> is arranged on the load sensors <NUM>, <NUM>, <NUM>. The load sensors <NUM>, <NUM>, <NUM> defines a weighing area S.

Using multiple load sensors eliminates the need for "cornering" which is an expensive and complex process of machining single point load cells with a particular implementation in mind.

Preferably, the patient support device <NUM> is mounted to the frame <NUM> such that a center of gravity G of the patient, when the patient is supported by the patient support device <NUM>, is positioned outside the weighing area S.

To achieve this, the patient support device <NUM> is mounted to the frame <NUM> such that a central point of the seat support portion <NUM> (depicted in <FIG>) of the patient support device <NUM> is positioned outside the weighing area S in at least one position of the patient support device <NUM> (shown in <FIG>).

This is associated with a number of advantages:
Firstly, the weighing arrangement is less sensitive to flexing or bending compared to a conventional weighing arrangement wherein the center of gravity of the patient is positioned inside the weighing area, particularly if the sub frame <NUM> is adapted to be more rigid than the frame <NUM> and/or other components of the patient handling apparatus which carries the load of the weight of the patient. This is due to frame taking the load from the patient and the offset patient not exerting any weight directly toward the sub frame. Thus, the weighing arrangement and sub frame may be considerably smaller while providing sufficient functionality, allowing for a more compact patient handling apparatus.

Secondly, the weighing arrangement according to the invention allows the patient to be weighed when the patient support device is at different vertical and tilted positions in relation to the load sensors while the sensors still provides a correct measurements and the calculated weight is accurate. In a conventional weighing arrangement wherein the center of gravity of the patient is positioned inside the weighing area, the uneven distribution of load between the load sensors would cause the calculated weight to be imprecise or incorrect.

Thirdly, the mounting of the sub frame on the load sensors prevents the patient handling apparatus to fall over or tip in case a load cell brakes, since a broken load cell only will cause the sub frame to drop in towards the frame, which does not affect the rest of the patient handling apparatus.

In one embodiment, the central point of the seat support portion <NUM> is positioned outside the weighing area S of the patient support device <NUM> in multiple positions of the patient support device <NUM>. In one embodiment, the central point of the seat support portion <NUM> is positioned outside the weighing area S of the patient support device <NUM> in all positions of the patient support device <NUM>. In one embodiment, the patient support device <NUM> is stationary, whereby the central point of the seat support portion <NUM> is stationary mounted outside the weighing area S.

Further referencing <FIG> and <FIG>, the base <NUM> comprises a horizontally extending portion <NUM>. The frame <NUM> extends in a substantially vertical direction. The horizontally extending portion <NUM> may be arranged to be adjacent to the floor, the frame <NUM> extending upwards from said horizontally extending portion <NUM>. Hence, the horizontally extending portion <NUM> may be provided with the wheels <NUM>, <NUM>. The base <NUM> may thus be a movable base <NUM>, in an alternative embodiment the base <NUM> may be a stationary base.

Referencing <FIG> in combination <FIG> and <FIG>, the weighing area S extends parallel to the horizontally extending portion <NUM>. Thus, the weighing area S may form a delimited plane SP, i.e. a plane delimited by the load sensors <NUM>, <NUM><NUM>, extending in a horizontal direction.

A central position axis CA extends through the central position of the seat support portion <NUM>. The central position axis CA extends in a vertical direction. The central position axis CA may be parallel to a normal, i.e. normal vector, SN of the delimited plane SP. The central position axis CA may extend at an offset horizontal distance D from said normal SN. For reference, the normal SN may extend from an outer edge of the delimited plane SP proximal to the central position axis CA.

The gravitational force from the center of gravity of a patient supported by the patient support device <NUM> extends parallel to the central position axis CA. Preferably, the gravitational force extends in a direction aligned with the central position axis CA.

Referencing <FIG> and <FIG>, the load sensors may be arranged on the base <NUM> or the horizontally extending portion <NUM> of the base <NUM>. Thus a first part of each load sensor <NUM>, <NUM>, <NUM> is arranged on the base <NUM>, whereby the sub frame <NUM> is arranged on a second part of each load sensor <NUM>, <NUM>, <NUM>. Said second part of each load sensor <NUM>, <NUM>, <NUM> is solely supported by the sub frame <NUM>. Accordingly, the second part of each load sensors <NUM>, <NUM>, <NUM> does not rest on the base <NUM>.

In one embodiment, a bottom side of the load sensors <NUM>, <NUM>, <NUM> is mounted to the base <NUM> or the horizontally extending portion <NUM> of the base <NUM>. The sub frame <NUM> is arranged on a top side of the load sensors <NUM>, <NUM>, <NUM>.

The horizontally extending portion <NUM> may comprise a support structure. In one embodiment the sub frame <NUM> may be arranged inside said support structure. The support structure may comprise a plurality of elongated support members forming a rectangular support structure.

The sub frame <NUM> is arranged on a first load sensor <NUM>, a second load sensor <NUM> and a third load sensor <NUM>. Thus an accurate weight may be calculated while keeping the number of sensors to a minimum and not having to resort to expensive single point load sensors.

The first load sensor <NUM> is arranged proximal to the frame <NUM>, i.e. the position where the frame extends from the horizontally extending portion <NUM>. Each of the second load sensor <NUM> and the third load sensor <NUM> is arranged distally from the frame <NUM> at a distance from the first load sensor <NUM> extending across the weighing area S. In one embodiment, said distance may extend along the horizontally extending portion <NUM>.

Thus, the first load sensor <NUM> may be arranged at a first edge <NUM> of the weighing area S, i.e. the delimited plane SP. The second load sensor <NUM> and the third load sensor <NUM> may be arranged along a second edge <NUM> of the weighing area S, i.e. the delimited plane SP. The second edge <NUM> is opposite to the first edge <NUM>.

The first edge <NUM> may be proximal to the frame <NUM>, i.e. the position where the frame <NUM> extends from the horizontally extending portion <NUM>. The second edge <NUM> may be distal to the frame <NUM>, i.e. the position where the frame extends from the horizontally extending portion <NUM>.

The sub frame <NUM> may comprise a first sub frame member <NUM> and a second sub frame member <NUM>. The second sub frame member <NUM> is arranged at a distance extending across the weighing area S from the first sub frame member <NUM>. Thus, the first sub frame member <NUM> may be arranged at the first edge <NUM> of the weighing area S and the second sub frame member <NUM> may be arranged at the second edge <NUM> of the weighing area S. In one embodiment, said distance may extend along the horizontally extending portion <NUM>. In one embodiment, the second sub frame member <NUM> extends parallel to the first sub frame member <NUM>.

The sub frame <NUM> may further comprise a third sub frame member <NUM> and a fourth sub frame member <NUM>. The third sub frame member <NUM> is connected to the first sub frame member <NUM> and the second sub frame member <NUM>. The fourth sub frame member <NUM> is connected to the first sub frame member <NUM> and the second sub frame member <NUM>.

Thus, the third and fourth frame member <NUM>, <NUM> may interconnect the first sub frame member <NUM> and the second sub frame member <NUM>. The third sub frame member <NUM> may extend parallel to the fourth sub frame member <NUM>.

The first sub frame member <NUM> may be arranged on the first load sensor <NUM>. The second sub frame member <NUM> and/or the third sub frame member <NUM> may be arranged on the second load sensor <NUM>. The second sub frame member <NUM> and/or the fourth sub frame member <NUM> is arranged on the third load sensor <NUM>.

Further referencing <FIG> and <FIG>, the sub frame <NUM> may be connected to the base <NUM> by means of the load sensors <NUM>, <NUM>, <NUM>. Thus, the sub frame <NUM> is only suspended to the base <NUM> by the load sensors <NUM>, <NUM>, <NUM>. The load sensors <NUM>, <NUM>, <NUM> may be configured to measure the load, i.e. tension, between the base <NUM> and the sub frame <NUM>.

A first portion, e.g. a first end of each load sensor <NUM>, <NUM>, <NUM> may be connected to the base <NUM>. A second portion, e.g. a second of each load sensor <NUM>,<NUM>, <NUM> may be connected to the sub frame <NUM>. Accordingly, the first end of each load sensor <NUM>, <NUM>, <NUM> may be fix to the base <NUM>. The second end of each load sensor <NUM>, <NUM>, <NUM> may be fix to the sub frame <NUM>.

The load sensors <NUM>, <NUM>, <NUM> may be load cells. As is well known in the field load cells are a type of transducers, which converts load into an electric signal readable by a processing unit such as a control unit. Load cells may be of hydraulic, pneumatic or strain gauge type. Preferably, the load cells may be strain gauge load cells due to their cost-efficiency. The load sensors <NUM>, <NUM>, <NUM> may be beam load cells such as double-ended shear beams.

The first load sensor <NUM> may be arranged proximal to the frame <NUM>. The first load sensor <NUM> is arranged and balanced such that a downwards directed load applied to the central position C of the seat support portion <NUM> results in a tension load in said first load sensor <NUM>. The tension load may extend along the first load sensor <NUM> in the delimited plane SP. The tension load may at least partially extend towards the central portion C of the seat support portion <NUM>, i.e. at least one load component vector of said load extends towards the central portion P.

In one embodiment, a central portion of the first sub frame member <NUM> is arranged on said first load sensor <NUM>.

In one embodiment, wherein the weighing arrangement comprises additional sensors, the first sub frame member <NUM> may be arranged on a plurality of load sensors, each being arranged and balanced such that a downwards directed load applied to the central position C of the seat support portion <NUM> results in a tension load in the load sensors. The tension load extend along each of the load sensors in the delimited plane SP.

In one embodiment, the first load sensor <NUM> may connect to the base <NUM>, i.e. the horizontally extending portion <NUM> at a position between the first sub frame member <NUM> and the second and third load sensor <NUM>, <NUM>.

The second load sensor <NUM> may be arranged distally from the frame <NUM>. Preferably, the second load sensor <NUM> is arranged adjacent to the connection between the third sub frame member <NUM> and the second sub frame member <NUM>.

The second load sensor <NUM> is arranged and balanced such that the measurable tension in the first load sensor causes a resulting measurable load in said second load sensor <NUM> via the sub frame <NUM>. The resulting tension load extend along the second load sensor <NUM> in the delimited plane SP.

The third load sensor <NUM> may be arranged distally from the frame <NUM>. Preferably, the third load sensor <NUM> is arranged adjacent to the connection between the fourth sub frame member <NUM> and the second sub frame member <NUM>.

The third load sensor <NUM> is arranged and balanced such that the measurable tension in the first load sensor causes a resulting measurable load in said third load sensor <NUM> via the sub frame <NUM>. The resulting tension load extend along the third load sensor <NUM> in the delimited plane SP.

In one embodiment, only the second sub frame member <NUM> is arranged on the second load sensor <NUM> and the third load sensor <NUM>. In one embodiment, the second load sensor <NUM> and third load sensor <NUM> solely connects the second sub frame member <NUM> with the base.

In one embodiment, the third sub frame member <NUM> and second sub frame member <NUM> are arranged on the second load sensor <NUM> and the fourth sub frame member <NUM> and second sub frame member <NUM> are arranged on the third load sensor <NUM>. Thus, the second load sensor <NUM> connects the third frame member <NUM> and the second sub frame member <NUM> to the base. Similarly, the third load sensor <NUM> connects the fourth sub frame member <NUM> and the second sub frame member <NUM> to the base.

As depicted in <FIG>, the patient handling apparatus may further comprise adjustable fixating means <NUM>. The adjustable fixating means <NUM> may be adapted to adjustably fixate the load sensors <NUM>, <NUM>, <NUM> to the sub frame <NUM> and/or to the base <NUM>. Thus, the tension in the load sensors <NUM>, <NUM>, <NUM> may be set by means of said adjustable fixating means <NUM> in a simple and user-friendly manner making the balancing of the weighing arrangement more efficient. This is particularly advantageous if the load sensors are load cells and more preferably beam load cells.

Balancing herein refers to the process of setting up a pre-set tension, i.e. load, in each load sensor and thus distributing the tension between the sub frame <NUM> and the base <NUM> via said load sensors to a pre-set reference value, i.e. load value.

Accordingly, the adjustable fixating means <NUM> is adapted to control a fixating force holding the load sensor to the base <NUM> and/or sub frame <NUM>. Thereby, balancing of the weighing arrangement may be achieved by adjusting the adjustable fixating means and consequently the fixating force.

In one embodiment, one of the portions of each load sensor is a fix end, i.e. fixedly mounted to the base <NUM> or the sub frame <NUM> and the other portion of each load sensor is connected of the other of the base <NUM> and the sub frame <NUM> by means of the adjustable fixating means.

The adjustable fixating means <NUM> may comprise adjustable fixating members <NUM>, <NUM>, <NUM>. The adjustable fixating members <NUM>, <NUM>, <NUM> are adapted to adjustably fixate each of the load sensors <NUM>, <NUM>, <NUM> to the sub frame <NUM> and/or the base <NUM>. The load sensors <NUM>, <NUM>, <NUM> may be mounted to the sub frame <NUM> and/or the base <NUM> by means of said adjustable fixating members <NUM>, <NUM>, <NUM>, whereby adjustment of said adjustable fixating members <NUM>, <NUM>, <NUM> causes adjustment of the fixating force holding each of the load sensors <NUM>, <NUM>, <NUM> to the base <NUM> and/or sub frame <NUM>.

In one embodiment, the adjustable fixating members <NUM>, <NUM>, <NUM> are adjustable fastening elements, such as bolts or screws or similar, connecting each of the load sensors <NUM>, <NUM>, <NUM> to the base and/or sub frame <NUM>. By providing torque to the adjustable fastening elements, the fixating force on the load sensor increases or decreases.

Turning to <FIG>, a patient handling apparatus <NUM> according to an embodiment is depicted. As previously described, the central position C of the seat support portion <NUM> of the patient support device <NUM> is positioned outside the weighing area S in at least one position of the patient support device. The seat support portion <NUM> may be considered a portion of the patient support device adapted to support the rear of a patient supported the patient support device <NUM>. The central point is consequently a centrally disposed point of said portion. The central point C is thus positioned at an offset horizontal distance relative the weighing area S in at least one position of the patient support device <NUM>. The offset horizontal distance may be defined as the offset horizontal distance D between the normal SN and the central position axis CA as previously described with reference to <FIG>. The normal SN may thus extend from a position along the second edge <NUM> of the weighing area S, i.e. a second edge of the delimited plane SP.

Notably, the central point C of the seat support portion <NUM> is relatively aligned with the center of gravity G (as depicted in <FIG>) of a patient seated on said seat support portion <NUM>, whereby it is ensured that the center of gravity G of the patient is outside the weighing area S as long as the central point C of the seat support portion <NUM> is outside said weighing area S.

The seat support portion <NUM> may be a separate element of the patient support device <NUM> or an integrated portion of a larger support part of the patient support device <NUM> which supports the rear of the patient supported by said patient support device <NUM>.

The weighing area S forms the delimited plane SP defined by the load sensors <NUM>, <NUM>, <NUM>, i.e. the connections between said load sensors <NUM>, <NUM>, <NUM> and the sub frame <NUM>. The weighing area S may be aligned with the sub frame <NUM>. As previously described, the sub frame <NUM> may form a rectangular shape. Thus, the weighing area S may form a rectangular delimited plane SP aligned with said sub frame <NUM>. The weighing area S may be parallel to said sub frame <NUM>.

<FIG> depicts a partial cross-section of the patient handling apparatus.

The patient handling apparatus may comprise a securing arrangement <NUM>. The securing arrangement <NUM> may be adapted to upon actuation lock the position of the sub frame <NUM> relative the base <NUM>. The securing arrangement <NUM> allows for keeping the sub frame <NUM> in a set position relative the base <NUM> once the calibration and balancing has been performed. Thus, the risk for the user having to re-calibrate and re-balance the weighing arrangement due to the sub frame <NUM> and base <NUM> moving relative each other by accident, impact or wear of the load sensors is reduced.

In one embodiment, the securing arrangement <NUM> may comprise a securing member <NUM> movably mounted to the base <NUM> and/or sub frame <NUM> for engaging the other of the base <NUM> or sub frame <NUM> and thereby fixate the base <NUM> to the sub frame <NUM>. The securing arrangement <NUM> may comprise at least one actuating member <NUM>, <NUM> adapted to move said securing member <NUM> between an actuated position and a non-actuated position. In the actuated position, the securing member <NUM> fixates the sub frame <NUM> to the base <NUM>. In the non-actuated position, the securing member <NUM> does not provide said fixation between the sub frame <NUM> and the base <NUM>.

The at least one actuating member <NUM>, <NUM> may be at least one actuation screw. Said actuation screw may extend in a vertical direction through and aperture of the securing member <NUM>, whereby rotation of said screw in a first direction moves the engagement member <NUM> towards the actuated position and in a second direction moves the engagement member <NUM> away from said actuated position.

In alternative embodiment, the securing member <NUM> may be a spring-loaded clamp. The spring-loaded clamp may be arranged to selectively lock, i.e. secure, the position of the sub frame <NUM> relative the base <NUM>.

Further referencing <FIG>, the securing member is adapted to engage the first sub frame member <NUM>, i.e. the sub frame member most adjacent to the frame <NUM>.

An issue arising with the mounting of loads sensors, is that tensioning strain will occur between the base <NUM> and the sub frame <NUM> due to the connection between the load sensor and the base. Turning to <FIG>, to address this, the patient handling apparatus may comprise a load sensor fastening arrangement for setting the correct tension of the connection between the load sensor and the base. Thus, according to an aspect of the invention a load sensor fastening arrangement is provided.

Accordingly, at least one of the load sensors <NUM>, <NUM>, <NUM> is mounted to the base <NUM> by means of a load sensor fastening arrangement. Preferably, each of the load sensors <NUM>, <NUM>, <NUM> is mounted to the base <NUM> by means of a load sensor fastening arrangement.

The load sensor fastening arrangement comprises a fastening element <NUM>. The fastening element <NUM> is adjustable along a tensioning axis T for setting the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. As depicted in <FIG>, the fastening element <NUM> may extend along the tensioning axis T.

The load sensor fastening arrangement further comprises supporting means <NUM>, <NUM>, <NUM>, <NUM>. The supporting means comprises a support element <NUM>, <NUM>, i.e. at least one support element <NUM>, <NUM> and a support member <NUM>, <NUM>, i.e. at least one support member <NUM>, <NUM>. The support element <NUM>, <NUM> or the support member <NUM>, <NUM> has a bowl shaped surface. The other of the support element <NUM>, <NUM> or the support member <NUM>, <NUM> has a dome shaped surface. The dome shaped surface may have a shape corresponding to the bowl shaped surface.

The bowl shaped surface and dome shaped surface may be spherical. The bowl shaped surface and dome shaped surface may face directions extending along the tensioning axis T. Preferably, the tensioning axis T may extend vertically. The dome shaped surface and bowl shaped surface may face each other. The dome shaped surface and bowl shaped surface may face each other relative the tensioning axis T.

Thus, the curvature of the bowl shaped surface and the curvature of the dome shaped surface engage such that a convex surface of the support member or support element engages with a corresponding concave surface of the other of the support member or support element.

Advantageously, the support member and support element may each comprise a substantially planar surface extending orthogonally to the tensioning axis T. The substantially planar surface may thus be arranged opposite to the bowl shaped surface or dome shaped surface of the support member or support element.

The curvature of the bowl shaped surface is arranged to engage the curvature of the dome shaped surface when the fastening element <NUM> is adjusted for increasing the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. Thus, the curvature of the bowl shaped surface or dome shaped surface of the support element <NUM>, <NUM> is arranged to be brought into contact with the curvature of the other of the bowl shaped surface and the dome shaped surface of the support member <NUM>, <NUM> when the fastening element <NUM> is adjusted for increasing the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. Accordingly, the support member and support element are arranged to engage upon adjustment of the fastening element <NUM> for increasing the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>.

The bowl and dome shaped surface creates a pivot point for the mounting of the load sensor which reduces the strain between the sub frame and the base. Further, the surfaces provides an indication of the correct tensioning and positioning of the load sensor. This makes it easier for an operator to match the individual positioning of the load sensors and consequently allows for easier calibration of the weighing arrangement.

Referencing <FIG>, a geometrical center point of the curvature of the bowl shaped surface of the support element <NUM>, <NUM> or the support member <NUM>, <NUM> may be arranged along an axis extending parallel to or in alignment with the tensioning axis T. Correspondingly, a geometrical center point of the curvature of the dome shaped surface of the other of the support element <NUM>, <NUM> and the support member <NUM>, <NUM> may also be arranged along said axis extending parallel to or in alignment with the tensioning axis T.

The curvature of the dome and bowl shaped surface may be arranged orthogonally to said axis extending parallel to or in alignment with the tensioning axis T. Thus at a point of intersection between said axis and the dome or bowl shaped surface, said dome or bowl shaped surface may be orthogonal to said axis. The support element and support member may be arranged orthogonally to said axis extending parallel to or in alignment with the tensioning axis T.

The dome shaped surface and the bowl shaped surface may be arranged to form a spherical joint upon engagement. Thus, adjustment of the fastening element <NUM> for increasing the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM> along the tensioning axis T causes fixation of said spherical joint.

As depicted in <FIG>, the dome shaped surface of the support element <NUM>, <NUM> is arranged to engage the bowl shaped surface of the support member <NUM>, <NUM> when the fastening element <NUM> is adjusted for increasing the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>.

Preferably, the load sensor <NUM>, <NUM>, <NUM> is mounted to the base <NUM> by means of the load sensor fastening arrangement and a fixed connection to the sub frame. In one embodiment, a first end of the load sensor <NUM>, <NUM>, <NUM> is connected to the base <NUM> by means of the load sensor fastening arrangement and a second end is connected to the sub frame by means of the fix connection.

In one embodiment, the support element <NUM>, <NUM> is provided with a through-hole. The support member <NUM>, <NUM> is also provided with a through-hole. The fastening element <NUM> may extend through said through-holes. The supporting means may be arranged along the tensioning axis T.

In alternative embodiment, the support member and support element may be arranged as protruding elements provided on the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. The support member and support element may be arranged offset from the fastening element <NUM>. Compared to such an arrangement, having the fastening element extending through the holes allows for a less complex and more user-friendly mounting of the load sensors.

Further referencing <FIG>, the fastening element <NUM> may extend in a hole provided in the base <NUM> and in a hole provided in the load sensor <NUM>, <NUM>, <NUM>. The load sensor <NUM>, <NUM>, <NUM> may be provided with a through-hole, whereby the fastening element <NUM> may extend through said load sensor <NUM>, <NUM>, <NUM>.

In one embodiment, the fastening element <NUM> may comprise a fixating portion <NUM>. The supporting means comprises a first support element <NUM> and a first support member <NUM> arranged between the fixating portion <NUM> and the load sensor <NUM>, <NUM>, <NUM> or the base <NUM>. In the depicted embodiment, the first support element <NUM> and the first support member <NUM> are arranged between the base <NUM> and the fixating portion <NUM>. The supporting means may further comprise a second support element <NUM> and second support member <NUM> arranged between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. The first and second support element are arranged to engage the first and second support member, respectively. Having support means in the form of a first and second support element and member allows for easier rotation of the fixating element around its center and further accommodates pivoting of the fastening element.

The planar surfaces of the support element <NUM>, <NUM> and the support member <NUM>, <NUM> may abut to corresponding planar surfaces of the load sensor, base or fastening element when the load sensor is in a mounted position.

As most clearly depicted in <FIG>, the fastening element may be provided with threads for engaging corresponding threads in the base <NUM>. Again referencing <FIG>, the fixating element may be a screw. The fixating portion may thus be a head of the screw. The support element(s) and support member(s) <NUM>, <NUM>, <NUM>, <NUM> may be washers. The washers may be arranged coaxially with the fastening element.

<FIG> depicts a schematic drawing of the control unit and associated components of the patient handling apparatus according to an embodiment, The patient handling apparatus comprises a control unit <NUM> operatively connected to the load sensors <NUM>, <NUM>, <NUM>. The control unit <NUM> is configured to calculate the weight of a patient supported by the patient support device <NUM> based on sensor signals from the load sensors <NUM>, <NUM>, <NUM>. Thus, the weight of the patient may be accurately calculated even though relatively simple and cost efficient load sensors are used, since only the tension between the base and the sub frame is required to be measured for an accurate calculated weight.

The sensor signals from the load sensors <NUM>, <NUM>, <NUM> are indicative of the load applied to each of said load sensors <NUM>, <NUM>, <NUM>. Further, the sensor signals from the load sensors <NUM>, <NUM>, <NUM> are indicative of the tension between the sub frame <NUM> and the base <NUM> through each of the load sensors <NUM>, <NUM>, <NUM>.

Accordingly, the control unit <NUM> may be configured to compare load data obtained from the sensor signals from the load sensors <NUM>, <NUM>, <NUM> when a patient is mounted to the patient support device with <NUM> reference load data obtained from the sensor signals from said load sensors <NUM>, <NUM>, <NUM> from when no patient is mounted to the patient support device <NUM> and thereby obtain the weight of said patient supported by the patient support device <NUM>. The reference load data may be obtained when the weighing arrangement has been calibrated and balanced. The reference load data may also be used during re-calibrating and re-balancing of said weighing arrangement.

The control unit is configured to calculate the weight of the patient supported by the patient support device by calculating a weight value indicating the weight of said patient supported by the patient support device based on the sensor signals from the load sensors <NUM>, <NUM>, <NUM>. The control unit may comprise a processor for calculating said weight.

In one embodiment, the control unit <NUM> may be configured to convert the sensor signals from the load sensors <NUM>, <NUM>, <NUM> to load data. In one embodiment, this may be performed by a converter operatively connected to the load sensors and control unit.

The patient handling apparatus may further comprise an indicating device <NUM> configured to display the weight calculated by the control unit <NUM>. The indicating device <NUM> may be in the form of a display with a graphical user interface (GUI). The indicating device <NUM> is operatively connected to the control unit <NUM> for presenting the weight. In one embodiment, the indicating device <NUM> may comprise a device configured to generate an audible or visible alarm or alert when the calculated weight of the patent exerts a threshold weight.

In one embodiment, the indicating device <NUM> is configured to display the load data obtained from the sensor signals, from the load sensors <NUM>, <NUM>, <NUM>. The load data may represent the load, i.e. tension, on each of the load sensors <NUM>, <NUM>, <NUM>. This is particularly advantageous during balancing and calibration of the weighing arrangement since it allows for tracking of the load exerted on each load sensor <NUM>, <NUM>, <NUM> during said balancing and calibration. This is particularly advantageous in combination with the adjustable fixating means described with reference to <FIG> since it allows for a user to control said adjustable fixating means while using the indicating device as reference during balancing of the weighing arrangement. The load data may be in the form of force tensors on each of the load sensors <NUM>, <NUM>, <NUM>.

In one embodiment, the indicating device <NUM> is configured to only display the aforementioned calculated weight. In one embodiment, the indicating device <NUM> is configured to display the weight and load data. In one embodiment, the indicating device <NUM> is configured to display only the load data.

In one embodiment, the indicating device <NUM> is further configured to display the reference load data. The reference load data may be displayed together with the load data further helping the user to achieve a correct balancing of the weighing arrangement.

Further referencing <FIG>, the control unit <NUM> may be configured to obtain load data from said sensor signals from the load sensors <NUM>, <NUM>, <NUM>. Further, the control unit <NUM> may be configured to calculate the weight value indicating the weight of the patient supported by the patient support device based on said load data.

The control unit <NUM> may be mounted to the base <NUM> of the patient handling apparatus or may for a separate device.

In one embodiment, the control unit <NUM> may comprise a communication interface, whereby the control unit <NUM> is further configured to transfer the aforementioned calculated weight value to an external device, such as a smart phone or computer. This may be an alternative to the indicating device <NUM> or be utilised together with said indicating device <NUM>.

According to an aspect, a patient handling apparatus <NUM> is provided. As previously described with reference to <FIG>, the patient handling apparatus <NUM> comprises the base <NUM> with the frame <NUM>. The patient handling apparatus further comprises the patient support device <NUM>. The patient handling apparatus further comprises the weighing arrangement <NUM> for weighing a patient supported by the patient support device <NUM>. The weighing arrangement comprises the sub frame <NUM> and the plurality of load sensors <NUM>, <NUM>, <NUM>, said sub frame <NUM> being arranged on the load sensors <NUM>, <NUM>, <NUM>. The load sensors <NUM>, <NUM>, <NUM> defines the weighing area S.

Again referencing <FIG>, the patient support device <NUM> is mounted to the frame <NUM> at a mounting point P such that said mounting point P is positioned outside the weighing area S (as depicted in <FIG>) in at least one position of the patient support device <NUM>. Thus the same advantages may be achieved even with a flexible and hanging type of patient support device, since it allows for positioning of the center of gravity G of the patient outside the weighing area S (due to the mounting point P being relatively aligned said center of gravity of the patient).

In one embodiment, the patient support device <NUM> is a patient sling. In one embodiment, the mounting point P may comprise a spreader bar or hanger for mounting of said sling.

The aforementioned patient handling apparatus may comprise any of the features previously described with reference to <FIG>.

According to an aspect a patient handling apparatus comprises the load sensor fastening arrangement described with reference to <FIG>. Thus, a patient handling apparatus <NUM> is provided. The patient handling apparatus comprises a base <NUM> with a frame <NUM> and a patient support device <NUM> mounted to the frame <NUM>.

The patient handling apparatus <NUM> further comprises a weighing arrangement for weighing a patient supported by the patient support device <NUM>. The weighing arrangement <NUM> comprises a sub frame <NUM> and a plurality of load sensors <NUM>, <NUM>, <NUM>. The sub frame <NUM> is connected to the base <NUM> by the load sensors <NUM>, <NUM>, <NUM>. In one embodiment, the sub frame <NUM> is arranged on the load sensors <NUM>, <NUM>, <NUM>.

At least one of the load sensors <NUM>, <NUM>, <NUM> is mounted to the base <NUM> by means of a load sensor fastening arrangement. The load sensor fastening arrangement comprises a fastening element <NUM>. The fastening element <NUM> is adjustable along a tensioning axis T for setting the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. The load sensor fastening arrangement further comprises supporting means <NUM>, <NUM>, <NUM>, <NUM>. The supporting means <NUM>, <NUM>, <NUM>, <NUM> comprises a support element <NUM>, <NUM> and a support member <NUM>, <NUM>.

The support element <NUM>, <NUM> or the support member <NUM>, <NUM> has a bowl shaped surface. The other of the support element <NUM>, <NUM> and the support member <NUM>, <NUM> has a dome shaped surface.

The curvature of the bowl shaped surface is arranged to engage the curvature of the dome shaped surface when the fastening element <NUM> is adjusted for increasing the tension between the load sensor <NUM>, <NUM>, <NUM> and the base <NUM>. The load sensor fastening arrangement may comprise any of the features described with reference to <FIG>.

According to an aspect, a method <NUM> for balancing the weighing arrangement <NUM> of the patient handling apparatus <NUM> according to any of the previously described embodiments is provided. Thus, the patient handling apparatus <NUM> comprises the base <NUM> with the frame <NUM> and the patient support device <NUM>. The weighing arrangement comprises the sub frame <NUM> and the plurality of load sensors <NUM>, <NUM>, <NUM>.

Referencing <FIG>, the method comprises obtaining <NUM> sensor signals from the load sensors <NUM>, <NUM>, <NUM>. The method further comprises adjusting <NUM> adjustable fixating means <NUM> to adjust the fixation of the load sensors <NUM>, <NUM>, <NUM> based on the sensor signals.

Thus, a method for balancing the weighing arrangement in a simple and precise manner may be achieved, since the user is able to balance the weighing arrangement directly based on the actual sensor signals from the load sensors.

The adjustable fixating means <NUM> for adjusting the fixation of the load sensors <NUM>, <NUM>, <NUM> may be the adjustable fixating means <NUM> described with reference to <FIG>.

In one embodiment, the method further comprises presenting <NUM> load data obtained from the sensor signals from the load sensors <NUM>, <NUM>, <NUM> on an indicating device <NUM> of the patient handling apparatus <NUM>. The indicating device <NUM> may be the indicating device <NUM> described with reference to <FIG>.

Thus, the weighing arrangement may be adjusted <NUM> based on the presented load data from the load sensors <NUM>, <NUM>, <NUM> on the indicating device <NUM> of the patient handling apparatus <NUM>.

The presenting <NUM> of the sensor signals from the load sensors <NUM>, <NUM>, <NUM> may further comprise individually presenting the load data obtained from the sensor signals from each load sensor <NUM>, <NUM>, <NUM> on the indicating device <NUM> of the patient handling apparatus <NUM>.

In one embodiment, the method may further comprise actuating <NUM> a securing arrangement <NUM> to lock the position of the sub frame <NUM> relative the base <NUM>. The method may comprise actuating <NUM> said securing arrangement after the adjusting <NUM> of the adjustable fixating means <NUM> to adjust the fixation of the load sensors <NUM>, <NUM>, <NUM> based on the sensor signals from the load sensor <NUM>, <NUM>, <NUM>.

The securing arrangement <NUM> may be the securing arrangement as described with reference to <FIG>.

In one embodiment, the method may further comprise calibrating <NUM> the patient handling apparatus by means of suspending a reference weight to the patient support device <NUM>. Thus, the weighing arrangement is tested in terms of giving a correct estimation and calculation of the weight. The step of calibrating <NUM> may be performed after the adjusting <NUM> of the adjustable fixating means <NUM>.

Claim 1:
A patient handling apparatus (<NUM>) comprising a base (<NUM>) with a frame (<NUM>) and a patient support device (<NUM>) mounted to the frame (<NUM>),
the patient handling apparatus (<NUM>) further comprising a weighing arrangement (<NUM>) for weighing a patient supported by the patient support device (<NUM>), said weighing arrangement (<NUM>) comprising a sub frame (<NUM>) and a plurality of load sensors (<NUM>, <NUM>, <NUM>), said sub frame (<NUM>) being connected to the base (<NUM>) by the load sensors (<NUM>, <NUM>, <NUM>),
wherein at least one of the load sensors (<NUM>, <NUM>, <NUM>) is mounted to the base (<NUM>) by means of a load sensor fastening arrangement,
characterised in that, the load sensor fastening arrangement comprising a fastening element (<NUM>) adjustable along a tensioning axis (T) for setting the tension between the load sensor (<NUM>, <NUM>, <NUM>) and the base (<NUM>), the load sensor fastening arrangement further comprising supporting means (<NUM>, <NUM>, <NUM>, <NUM>), the supporting means (<NUM>, <NUM>, <NUM>, <NUM>) comprising a support element (<NUM>, <NUM>) and a support member (<NUM>, <NUM>), wherein the support element (<NUM>, <NUM>) or the support member (<NUM>, <NUM>) has a bowl shaped surface and the other of the support element (<NUM>, <NUM>) and the support member (<NUM>, <NUM>) has a dome shaped surface, wherein the curvature of the bowl shaped surface is arranged engage the curvature of the dome shaped surface when the fastening element (<NUM>) is adjusted for increasing the tension between the load sensor (<NUM>, <NUM>, <NUM>) and the base (<NUM>).