WO2018116299A1 - Weight scales systems and methods - Google Patents

Abstract

A weight scale system for measuring the weight of an object, which includes a bed section, a vertical separator actuator and a controller. The bed section includes a lower-platform, an upper-platform and weight sensor assemblies located on the lower-platform, each includes at least one weight sensor. The bed section further includes and at least one vertical-separator. The vertical-separator actuator is coupled with the vertical-separator and with the controller. The controller Is further coupled with the weight sensors. The controller directs the vertical-separator actuator to operate the bed section in at least two modes, a referencing mode in which the vertical-separator detaches the upper-platform from the weight sensor assemblies, thereby enabling the referencing the weight sensors, and a weighing mode, in which the vertical separator re-attaches said upper-platform with the weight sensor assemblies, such said that the weight associated with, said upper-platform is fully applied on the weight sensors.

Description

WEIGHT SCALES SYSTEMS AMD METHODS

FIELD OF THE DISCLOSED TECHNIQUE

The^■ disclosed technique relates To weight scales in general, and to systems and methods for weight scales systems for hospital beds in particular.

BACKGROUND OF THE DISCLOSED TECHNIQUE

Weighing immobile object, specificall objects which cannot be lifted by a human may be challenging, for example, weighing patients on a hospital bed Known in the art techniques include placing an inflatable mattress under the patient. A further challenge is referencing the weight scales.

PCT Application Publication VVG 1990/00292? to Broome, entitled "Method and device for weighing, especially of seriously ill patients confined to bed" describes a system for determining the weight of a patient confined to a bed. The system includes an inflatable mattress, a compressor, a compressed air container and pressure sensors. The inflatable mattress is laced beforehand an inflatable mattress in the bed under the patient. When weighing is carried out, the mattress Is Inflated with compressed air until the patient is balanced. The compressed-air supply is interrupted, and a previously measured exact quantity of air is supplied to the mattress. The change of pressure caused by the patient's load on the exact quantify of air supplied to the mattress is measured and converted into weight The exact quantity of air supplied by filling the compressed air container until the pressure therein reaches a predetermined level The air in the container is then transferred to the inflatable mattress,

U.K. Patent GB2453371 B to Robinson, entitled "Mattress pump apparatus controller, mattress pump apparatus, mattress and method of controlling a mattress"^' directs to a system which detects when a weight is placed on th mattress and then determines the weight of the mattress. To that end, the mattress is filled to predetermined initial pressure. When a load is placed on the mattress, a change in the pressure is detected. Thi change relates to the weight of the patient

U.S. Patent 5,881 ,582 to Flanagan ei ai, entitled "Patien weighing system" directs to a patient weighing system which includes load sensing casters or load lift modules installed on a hospital bed. The casters and load lift modules each include pneumatic lifts. The lifts ar operative to load and unload the weight of the device onto a piezoelectric load cells. The load cells are electrically connected to control units whic include visual displays. In operation, the operator then pumps a foot pedal to pressurize the pneumaiic lines and to expand chambers in each of the housings. This unloads the load cells. After wasting a brief period of time which relates to the discharge time of the load ceils, the processor resets itself so that the signal from each load cell is considered to be a zero value.

SUMMARY OF THE PRESENT DISCLOSED TECHNIQUE

It .is an -object of the disclosed technique to provide a novel weig t: scale system and method system tor measuring the weight of at least one object. In accordance with the disclosed technique; there is thus s provided a system for measuring the weight of at least one object. The weight scale system Includes a bed section, vertical separato actuator and a controller. The bed section includes a lower platform, an upper platform for bearing the weight of the at least one object, at least one weight sensor assembly and at least one vertical separator. Th at leasto one weight sensor assembly includes at least one weight sensor, and is located on the Sewer platform. The at least one weight sensor is operable to measure weight applied thereon. The at least one vertical separator is operable to detach the opper platform from the at least one weight sensor assembly. The at least one vertical separator actuator Is coupled with thes vertical separator and is operable to operate the vertical separator. The controller is coupled with the at least one weigh sensor and with the vertical separator actuator. The controller directs the vertical separator actuator to operate the bed section in at least two modes, a referencing mod and a weighing mode. In the referencing mode the vertical0. separator detaches the upper platform from the at least one weight sensor assembly, thereby enabling the referencing of the at least one weight sensor, in the weighing mode the vertical separator re-attaches the upper platform with the at least one weight sensor assembly, such that the weight associated with the upper platform is fully applied on the at leasts one weight sensor.

in accordanc with another- aspect of the disclosed technique, there is thus provided a method for referencing at least one wei ht sensor in a weight scale system. The method incudes the procedures of detaching an upper platform of a bed section of a weight scale from the ato least one sensor such that no weight is applied on the at least one weight sensor and referencing the at feast one weight sensor.. The feed section includes a lower platform,, the upper platform bearing the weight of at least one object and the at least one weight sensor. The at least one weight sensor is located on the Sower platform and operable to measure weight applied thereon. The method further includes the procedure of reattaching the upper platform to the at least one weight sensor such that the upper platform and the load thereon apply their full weight on the at least one weight sensor.

BRIEF DESCRIPTION OF THE DRAWI GS

The disclosed technique will fee understood and appreciated room fuily from the foiiowing detailed description taken in conjunction with the drawings in which;

Figure 1 is a ^'schematic illustration of a weighing scenario, in accordance with an embodiment of the disclosed technique;

Figure 2, is a schematic illustration of a mattress weight scales system constructed and operative in accordance with another embodiment of the disclosed technique;

Figure 3 is a schematic illustration of method for measuring the weight of an object, placed on top of a mattress weight scale, operative in accordance with a further embodiment of the disclosed technique;

Figures 4/V4D are schematic illustrations of^" a mattress weight scales system, constructed and operative in accordance with another embodiment of the disclosed technique;

Figures 5A-5D are schematic illustrations of a valve assembly connected to a pump, in accordance with a further embodiment of the disclosed technique

Figures 6A-6D are schematic illustrations of a weighing mattress, constructed and operative in accordance with another embodiment of the disclosed technique;

Figure 7 is a schematic illustration of a weighing mattress, constructed and operative in accordance with a further embodiment of the disclosed technique;

Figure 8 is a schematic illustration of a weighing mattress, constructed and operative in accordance with another embodiment of the disclosed technique;

Figure :9 is a schematic illustration of a weighing mattress, in accordance with a further embodiment of the disclosed technique; Figures 10A, 10B and 1.0C are schematic illustrations of a eight scales system, constructed and operative in accordance with another embodiment of the disclose technique;

Figures 11 A, 116 arid 11C are schematic illustration of an exemplary bed section, constructed and operative in accordance with a further embodiment of the disclosed technique;

Figures 2 A and 128 are a schematic illustration o an exemplary bed section, constructed and operative in accordance with another embodiment of the disclosed technique;

Figure 13A i schematic Illustration of an exemplary bed section, constructed and operative in accordance w th a further embodiment of the disclosed technique;

Figure 138 is a schematic illustration of an exemplary weight sensors, constructed and operative in accordance with a further embodiment of the disclosed technique; and

Figure 14 is a schematic illustration of a weight scale system, constructed and operative in accordance with another embodiment of the disclosed technique; and

Figur 15 is .a schematic illustration of a method for referencing weight sensors in a bed section, operative in accordance with a further embodiment of the disclosed technique.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Trie disclosed technique overcomes the disadvantages of the prior art by providing a system and method for determining the weight of immobile objects, specifically patients lying on a bed. According to the disclosed technique, a weighing mattress is placed between the bed platform and the bed mattress. The weighing mattress includes weighing segments and reference segments. The weighing segments and the reference segment are full with a fluid. The weighing segments are ail fluidally coupled with eac other and with a weight sensor. The reference segments are all fluidally coupled with each other and with a reference sensor. The weighing segments and the referenc segments are mechanically coupled ^'therebetween. The weight sensor measures the pressure of the fluid in weighing segments. The reference sensor measures the pressure of the fluid In reference segments- A processor subtracts the reference pressure form the weighing pressure to determine a difference pressure and determines the weight of the object placed on top of the bed according to this difference pressure. According to the disclosed technique, and as further elaborated below, the Weight of the object is not applied on reference segments. Thus, the pressure in the reference segments is only affected by changes i environmental conditions. Subtracting the reference pressure from the weighing pressur ^'alleviates the effects of the environmental conditions on the pressure of the fluid in the weighing segments

Reference is now made to Figure 1 , which is a schematic illustration of a weighing scenario, generally referenced 100, in accordance with an embodiment of the disclosed technique:.. In scenario tOO, a patient 102 lies on a bed 104, on top of a mattress 106. A weighing mattress 108 is located between th platform 1 10 of bed 104 and mattress 106, Scales 112 measure the weight of patient 102, as further elaborated below. Scales 1 12 may indicate to a use the weight of patient 102, For e m le, scales 1 12 present the weight of patient 112 on a display.

Reference is now made to Figure 2, which is a schematic illustration of a mattress weight scales system, generally referenced 150, s constructed and operative in accordance with another embodiment of the disclosed: technique. Mattress weight scales system 150 includes a weighing mattress 152, a weight sensor 154, a reference sensor 158, a processor 158, and a weight indicator 1β0. Weighing mattress 152 Includes a plurality of weighing segments 184;, 16½ 164₃, 164_N and ao plurality of reference segments 166.†, 188₃, 186₃, 16%, where H and M are integers.

Reference segments I66_it 186g, 166₃, 186 are interleaved between weighing segments 16 _}i 164₂, 184_3i !84_H along the mattress. Figure 2 depicts th cross section of weighing segments 184},s 184_& 164_3. «... 164 and reference segments 166,, 16%, 186₃₍ ...... 166_w.

In Figure 2, weighing segments 184 64₂, 184_a> 164_N and reference segments 168}, 186_Ss 186_3l , ., , ^'16% are exemplified as tubes. In the example depicted In Figure 2, the thickness of weighing segments 164_1:> 184_s> 164₃₍ ,,,, 1$4_N is larger than the thickness of reference segments0 168,, 166₂, 1.6%, 166_M. When weighing segments 184_{1; !} 164*,. 164₃,

164 and reference segments 168,, 16%, 166_3i 18% are embodied as tubes, the diameter weighing segments 184 _:! 16 2, 164_3> 164_N is larger than the diameter of reference segments 186,, 168_?, 1^'6 , ... . 166 .

5 Each one of weighing segments 184†, 16% 164¾, .... 164_N and reference segments 16% 16% 166_¾, „.., 186_M is full with a fluid (e.g.. water, oil, gas). Weight sensor 154 and reference sensors 166 are typically fluid pressure transducers converting pressure applied on the sensor to a corresponding electrical signal. Weight indicator 180 is,_: for0: example, a display which presents the user with a numerical representation of the weigh! of the object being weighted.. As a further example, weight indicator 160 a sou d indicator producing a sound uttering the weigh! of the object,

!n the example brought forth in Figure 2, weighing segments 184-i, 184_¾; i 4_3f 164_N are mechanically coupled with reference segments 168^ 166₂, 188_3t .... 166M- Weighing segments 184*, 164_2s 164_3> 164* .are fiuidally coy pled therebetween. The term 'fiuidally coupled' relates herein to the abilit of fluid to freely flow between the segments and components. Reference segments 166†, 166₂, 168₃, .... 88 a also fiuidally coupled therebetween. It is, however, noted that weighing segments 164 _;, 164_2s 18 184_& are not fiuidally coupled with reference segmenis 1.68.†, 18¾_< †66₃, 168M. Furthermore* weighing segments 164 ₍ 164_2s 164₃, .... 164_N are fiuidaily coupled with weight sensor 154. Reference segments 166†, 186_§, 188_3> .„, 186_¾ a e fiuidally coupled with reference senso 158. Processor 158 is coupled with weight sensor 154, reference sensor 156; and weight indicator 186.

Weight sensor 15 measures the pressure of the fluid ^'In weighing segments 164 ₍ 184₂, 164₃, 164 and provides processor 152 with a signal indicative of the measured pressure. Similarly reference sensor 158 measure the pressure of the fluid in reference segments 1.88†, .682, 168₃, 166_¾ and provides processor 158 with a signal (e.g., electric voltage or electric current) indicative of the measured pressure. The term 'measure⁵ relates herein to the process converting pressure applied on the sensor to an electrical signal corresponding to a pressure applied on either weight sensor 154 or reference sensor 158. The term "measurement:' refers herein to the signal relating to the pressure in either weight sensor 1:54 or reference sensor 158 (i.e., either the signal produced by weight senso 154 and reference sensor 56 or a sampled version thereof). The measurement from weight sensor 154 is referred to herein as "the weighing measurement¹ and the measurement form reference sensor 168 is referred to herein as the reference measurement^*. Also the pressure in weighing segments 164 _; 84_2; 184₃, .... i&4_H is referred to herein as Ihe eighing pressure' and the pressure in in reference segments ΐ68ι·, 188;_?, 108_¾ ... , 16¾ Is referred to as the reference pressure'

When measuring the weight of an objeci (e.g., a patient), the object is placed on top weighing mattress 152. However, weighing_, segments 184 _s 1S4_2i 184¾. 16 ^ are affected by the weight of the object. The change in pressure of the fluid in weighing segments 184; _> 164?_., 164_¾, 184_H relates to the weight of the object as well as to effects of environmental conditions. However, the effects of the environmental conditions (i.e., at least of ambient temperature) on the measurements are unknown. Furthermore, th inventors have discovered that these environmental effects are not uniform along the length of the weighing mattress. Since the reference segments are not affected by the weight of the object, the pressure of the fluid In these segments is affected only by the change in environmental conditions along the mattress. To determine the weight of the object on top of weighing mattress 152, processor 158 subtracts the reference measurement from: the weighing measurement and determines the weight of the object on weighing mattress 152 therefrom as further explained ^'below. Thus, processor 158 alleviates the effects of the environmental condition on th weighing measurement, in other words, processor 158 determines a difference measurement by subtracting the reference measurement from the weighing measurement and determines the weight of the objeci on weighing mattress 152 according to this difference measurement as further explained below.

Prior to use, mattress weight scale system 150 is calibrated to determine a correspondence between the difference measurement determined from the weighing measurement and the reference measurement, and ihe weight of the object on top of weighing mattress 152. To that end, each of a plurality of objects of different known weights is placed separately on weighing mattress 152, and processor 158 determines a respective differenc measurement as explained above. Processor 158 also determines a difference -measurement when no weight is placed on weighing mattress 152. Since the weights placed on weighing mattress 152 are known, a correspondence is determined between the difference measurement respective of each weigh! and the respective weight. This correspondence is employed to determine the weight of the object on to of weighing mattress 152 according to the determined difference measurement. This correspondence may take the form of a Look Up Table (LUT), Alternatively, a curve may be fitted to the measured weights and corresponding difference measurements. The environmental conditions during the calibration should be within the designed operational range of the mattress weight scale,

Reference is now made to Figure 3, which is a schematic illustration of method fo measuring the weight of an object, placed on top of a mattress weight scale, operative in accordance with a further embodiment of the disclosed technique. In procedure 180, the pressure in the pressure in the weighing segments is measured. With reference to Figure 2, weight sensor 154 measures the pressure in the weighing segments.

In procedure 182, the pressure in the reference segments are measured. With reference to Figure 2, weight sensor 156 measures the pressure in the weighing segments.

in procedure 184, the reference segments measurement is subtracted from the weighing segments measurement to determine a difference measurement. With reference to Figure 2, processor 1-58 subtracts the reference measurement from the weighing measurement.

In procedure 186, the weight of the object is determined from the difference measurement. The weight of the object Is determined from the difference measurement, according to a correspondenc between various different weights and a corresponding ilifference measurement This correspondence is determined before using the mattress weight scale. With reference to Figure 2, processor 158 determines the weight of the object according to the difference measurement

When the ^{' "}fluid employed in the weighing and referenc segments is gas, the gas inside the segments may leak between measurements either from the weighing segments, or from reference segments, or from both. These variations in the amount of re-filled gas may result in .variations in the pressure of the gas inside the mattress weight scale, which ma result in ambiguity in the determined weight To alleviate this ambiguity, the weighing mattress of a mattress weight scales system should be refilled with gas before each weighing. To that end, a re-fi!ling mechanism is connected to: the weighing and reference, segments.

Reference is now made to Figures 4A-4D, which are schematic illustrations of a mattress weight scales system, generally referenced 200 , constructed and operative in accordance with another embodiment of the disclosed technique, Mattress weight scales system 200 includes a weighing mattress 202, a valves assembly 204 and a pump 206, Mattress weight scales system 200 further includes a weight sensor 208, a reference sensor 210. a processor 212, and a weight indicator 212. Weighing mattress 202 includes a pluralit of weighing segments 218_?, 21%, 218_3; 218 and a pluralit of reference segments 220 >, 220;, 220_$·, 220.M where N and are integers. Valve assembl 204 includes values 224, 220, 228, .230, 232 and 234. in the example brought forth in Figures 4A-4D, valve assembly 204 is depicted as including six two-way values. However, valve assembly 204 may be configured^' with three, three-way valves. Also, for the sake of simplicity of the explanation which follows, the ports of each one of two-way valves 224, 226, 228, 230, 232 and 234 are number in Figures 4A-4D, 1 and 2

Weighing segments 21 <, 21¾>. 213_¾, ,„.,. 218_M and reference segments 220,, 220₂, 220_$, ... 220^ are similar to weighing segments im 164₂, 1643, ,, , , 164_N and reference segments 166,,_. 166_2; 168₃, 166M described hereinabove in conjunction with Figure 2. As such, reference segments 220 22C½, 22{½, 220^ are interleaved between weighing segments 218_{1 (} 21S¾, 21 S_3l 218^ along the mattress. Figures 4A-4D depicts the cross section of weighing segments 218ι , 21 _2s 218₃, 218N and reference -segments . 220, , 220₂, 22Q_a, .... 220_f# In Figures 4A-4D, weighing segments 218-5 , 21%, 218₃, 218_N and reference segments 220 220₂, 220_3! 220M are -exemplified as tubes. In the example depicted in Figures the thickness of weighing segments 218; , 218₂, 218₃, 218^ IS larger than the thickness of reference segments 220,, 220₂, 220_¾ 22%«.

Each one of weighing segments 218,, 2 %, 21 %, ..... 1 %j and reference segments 220, , 220,₂, 220₃, 220^ is full with a fluid (e.g. , water, oil, gas). Weight sensor 208 and reference sensors 210 are typically fluid pressure transducers converting pressure applied on the sensor to a- corresponding electrical signal. Weig t indicator 214 is, for example, a display which presents the user with a numerical representation of the weight of the object being weighted. As a further example, weigh., indicator 214 a sound indicator producing a sound uttering the weight of the object.

Also similar to as described above in conjunction with Figure 2, weighing segments 218>, 218 , 21 , .... 218_f- are mechanic-ally coupled with reference segments 220,, 22Q₂, 220₃, ... , 220$; Weighing segments 218, , 2.18^' ₂, 2 8₃, ..... 2^'\ are fluidally coupled therebetween. The term 'flu_.idally coupled' relates herein to the ability of fluid to freely flow between the segments- and components. Reference segments 220,, 220₂, 220_s, ...₅ 22¾ are also^■.^' fluidally coupled therebetween. It is, however, noted that weighing segments 2W 21:8s, .218_¾ 21%, are not fluidally coupled with reference segments 22Q 22G_2> 220₃, ,,, , 22Q , Furthermore, weighing segments 21βι, 21S_2> 218₃, 2 8^ are fluidally

& coupled wth weight sensor 208. Reference segments 220%, 22Q₂. 220a, ... , 20M sre fluidally coupled: wit reference sensor 210. Processor 212: is coupled with pump 206, weight sensor 208, reference sensor 210, and weigh! indicator 212. Furthermore, weighing segments 218_ts 218₂, 218₃₍ 218 and reference segments 22Q , 220_2i 220₃, 22Q_m are fluidallyo coupled with valve assembly 204. Specifically, In the example brought forth in Figures 4A-40, port 1 of valve 228 and port 2 of valve 234 are fluidaiiy coupled with a gas reservoir (e.g. , ambient air - net shown). The output port of pum 206, port 2 of valve 228 and port 2 of valve 226 are fluidally coupled therebetween. The input pod of pump 208, port 1 ofs valve 223 and port 1 of valve 280 are fluidally coupled therebetween. Port 2 of valve .230, reference segments 220 _; 220_2ί 220s, 220_w and port 1 of valve 232 are fluidally there between. Port 2 of valve 224, port 1 of valve 226 and port 2 of valve 232 are fluidally coupled therebetween. Port 1 of valve 224 is fluidaiiy coupled .with weighing segments 2t8_t, 218_¾Q 218¾, ... , 21 _H.

As mentioned above, prior to measuring the weight of the object, and optionally while the object Is placed on top weighing mattress 202, weighing segments 218_{J :} 218₂, 218₃, 218_H are fifed gas by fitting reference segments 220^ 220_¾5 220_S) 220_¾i w th gas until the gas in5 reference segments 220 , 220_:?, 220_¾, 220M reaches a predetermined pressure, and transferring the gas weighing segments 218,, 218₂, 218₃,

218N. This may be repeated for a predetermined number of times. Each filling of reference segments 220,, 220₂, 220_3> ..... 220_&, with gas, and the transfer of gas to weighing segments 218₅, 218^, 2 63, .... 218M ISo referred to herein .as a 'filling cycle¹.- After completing the predetermined number of filling cycles, reference segments 2?.0 _: 22¾, 2203, 220^ are once again filed with gas -until the gas therein reaches the predetermined pressure. A fii!ing cycle and the filling of reference segments 22Q 22Q₂, 220^: ₃, 2 0^ once again with gas, until the gas therein reaches the predetermined pressure, is referred to herein as "filling the mattress'

Similar to as described above, the pressure of the gas in reference segments 220,, 22Q_2f 220_¾ 22¾, is measured by reference sensor 210 which provides the weighing measurement to processor 212. The above predetermined pressure serves as the reference pressure as well. Thereafter, weight sensor 208 measures the weighing pressure when the object is placed on fop of weighing mattres 202 and provides the weighing measurement to processor 212. Processor 212 subtracts the reference measurement from the weighing measurement to determine a differe e measurement. Processor 212 determines the weight of the object according to- a correspondence between various the difference measurements and respective weights (i.e., simitar to as described above). If Is noted that the same number of Filling cycles should be employed when determining the weight of the object on top of eighing mattress 202 and when determining the correspondence between various the .difference measurements and respective weights, It is further noted that, similar to as described above in conjunction with Figure 2, since only weighing segments 218i , 21B₂, 218_3< 218_N are affected by the weight of the object, the change in pressure of the fluid in weighing segments 8- , 2.182, 218₃, ..... 218>¾ relates to the weight of the object as well as to effects of environmental conditions. Since reference segments 220, , 22% 220_{3 :} 220M ar not affected by the weight of the object, the pressure of the fluid in these segments Is affected only by the change in environmental conditions along the mattress. By subtracting the reference measurement form the weighing measurement,_, processor 202 alleviates the effects of the unknown environmental conditions on the weighing measurement.

As mentioned above, prior to weighing the object a predetermined number of filling cycles are performed to fill weighing segments 21.8_1s 21B_& ,2 S_¾1 ...... 2 8_H with gas, after which reference segments 220_t> 220_2: 220_¾ 2 0¾ are filled with gas until^' the ps therein reaches a predetermined pressure. Following Is a description of filling the mattress. With reference to Figure 4A, initially any residual gas is emptied from weighing mattress (i.e., from both weighing segments 218_1s 218g, 218_¾ 21% and reference segments 220_t, 220₂, 220₃, 220 ). To that end, processor 212 directs valves 226 and 234 to the open state thereof and directs valves 224, 228, 230 and 232 to the closed state thereof. The open state relates to a state where no fluid can flow between the ports of the valve. The closed state, indicated by a double headed arrow, relates to a state where fluid can flow between th ports of the valve marked by the doubled headed arrow. Processor 212 then activates pump 206. The gas from weighing segments 218₅ , 218?, 21% 2 ^ flows through valves 224, 232, 230, throug pump 20 and through valve 224 to the gas reservoir. The gas from reference segments 220 _{; ;} 220_{;? !} 220_¾, 220 flows through valves 230, through pump 208 and through valve 224 to the gas reservoir. Processor 212 shuts down pump 206, for example, when the pressure of the gas in weighing segments IS_{1 :} 2 8_S, 2 8₃, 218_N and reference segments 220<, 220-, 220₅, 220_M reaches zero.

With reference to Figure 48, reference segments 220·!, 22G_2> 22Ο3, 22C¾ are filled with gas until the gas therein reaches a predetermined: pressure. To that end, processor 212 directs vales processor 212 directs valves 224, 228 and 230 to the open state thereof and directs valves 226, 232, and 234 to the closed stale thereof, ^•Processor 21 then activates pump 208 and the gas flows from the gas reservoir, through valve 234, pump 206, valve 232 and valve 234 into reference segments 22G_f) 220¾ 22% .« « , 2.20&J. When the pressure of the gas in reference segments 220 _¾, 22% 220-,, 220M reaches a predetermined level, processor 212 shuts down pump 208

With reference to Figures- 4C, the gas In reference segments 220 ₍ 22% 220-5, 220 is transferred to weighing segments 218^ .218₂,

218₃, , 218K_¾. TO that end, processor 212 directs valves 220, 232 and

234 to the open stat thereof and valves 224, 228 and 230 to the closed state thereof. Processor 212 then activates pump 206 and the gas flows from reference segments 220; , 220₂, 220_; 22Q_U flows through valve 232, pump 206₁ valve 226 and valve 224 into weighing segments 218_{1 t}

Thereafter, reference segments 22Q_{1 (} 220_2> 220₃, , , , , 2 0^ similar to as described above Ih. conjunction with Figur 38, Thereafter, with reference to Figure 40, processor 212 directs valves 224, 226. 228, 230, 232 and 234 to the open state thereof and acquires the . eighing measurement and the reference measurement as desc ibed above.

As mentioned above, valve assembly 204 (Figures 4A-4D) may b implemented with three three-way valves. Specifically the valve assembly may be implemented with three three-way valves where each valve has five states (i.e., all ports are closed, ail ports are open and each pair of ports is open}. Reference is now made to Figures 5A-50, which are schematic Illustrations of a valve assembly 250 connected to a pump 252. in accordance with a further ^'embodiment of the disclosed technique. Port 254 is fluidaHy coupled with weighing segments (not shown), port 256 is fluidally coupted -with reference segments (not shown) and port 258 is fiuidally coupled with a gas reservoir (e.g., ambient air ~ not shown). Figure 5A depicts the states of th valves when the weighing and reference are being emptied. Figure .58 depicts the state of the valves when th reference segments are being filled with gas.: Figure 5G depicts the state of the valves when the gas is being transported from the referenc segment to the weighing segments and Figure 5D depicts the ^•state of th valves when weight s being measured.

Reference is now made to Figures 8A-8D, which are schematic illustrations of a weighing mattress, generally referenced 300, constructed and operativ in accordance wit another embodiment of the disclosed technique. Weighing mattress 300 includes a plurality of weighing segments, such as weighing segment 302 and a plurality of reference segments, such as weighing segment 304, interleaved between the weighing segments, With reference to Figure 8A, eac weighing segment includes a respective fluid inlet/outlet such as fluid inlet/outlet 306;. Each reference segment also includes a respective fluid inlet/outiei such as fluid inlet/outlet 308. The weighing segments are fluidaiiy coupled therebetween with weighing connectors, such as weighing connected 310 which connects the. fluid Net/outlet of each adjacen pair of weighing segments. Similarly, the reference segments are fluidaiiy coupled therebetween with reference connectors, such- as- weighing connected 312 which connects the fluid inlet/outlet of each adjacent pair of reference segments.

With referenc to figure 6B, weighing mattress 300 is depicted placed on a bed 314. Also a weight sensor 318 Is fluidaiiy coupled with the weighing segments and a reference sensor 318 is fluidaiiy coupled with the reference segments. With reference to Figure 6.G and §D, depicted therein are isometric views of one side of weighing matters 300, placed on heel 314, and a mattress 320 placed on top of weighing mattress 300. Figure SC depicts one sid of weighing mattress 300 and Figure 8D depicts the other side of weighing mattress 300,

Reference is now made to Figure 7, which is a schematic illustration of a weighing mattress, generall referenced 400, constructed and operative in accordance with a further embodiment of the disclosed technique. Weighing mattress 400 is divided Into a plurality of inflatable sections, such as sections 40¾ and 4Q2₂. Each section is coupled with an adjacent section. Each section is welded such as to create a structure of two interleaved rakes. The fingers of one rake constitute weighing segments and the base of this rake fluidaiiy couples the weighing segments. The fingers of the other rakes constitute reference segments and the base of this other rake fluidaiiy couples the reference segments. Each rake in each section is independently inflatable. The infiatabie rake, corresponding to the weighing segments, is fluidaiiy coupled with a corresponding rake in an adjacent section vi connectors, such as connectors 408, which are coupled -with the fluid inlet/outlets of each rake. The infiatabie rake, corresponding to the reference segments, i fluidaiiy coupled with a corresponding rake in an adjacent section via connectors, such as connectors 410, which are coupled with the fluid inlet/outlets of each rake.

Reference Is now made to Figure 8, which is a schematic illustration of a weighing mattress, generall referenced 450, constructed and operative in accordance with another embodimen of the disclosed technique. Weighing mattress 450 is place on a bed 452. Weighing mattress 450 includes a plurality of weighing segments such as weighing segment 454 and a plurality of referenc segments such as reference segment 458. The weighing segments and the reference segments exhibit the same thickness. However, only the weighing segments are affected by the weight of the objected, since the weighing segments are positioned on steps, such as step 458 (e.g.. made from Stymfoam). The weighing segments and th reference segments are coupled ith the mattress, for example, with straps, which are coupled (e.g.., glued or welded) to a base.

In some scenarios, the accuracy of the weight scale mattress may be affected by a heat source (e.g., a human hand) which comes into contact or is located in proximity to the weighing mattress, more so if the heat source effects either the weighing segments or the reference segments. To reduce the effects of such a heat source, ihe weighing and reference segments may he covered with thermal Isolation foils. These isolation foils reduce the effects of a heat source which may come into contact with the mattress weight scale. Reference s: now made to Figure 9, which is a schematic illustration of a weighing mattress, generally referenced 500. in accordance with a further embodiment of ihe disclosed technique. Weighing mattress 500 is placed on top of a bed 502. Weighing mattress 500 includes a plurality of weighing segments suc as weighing segment 504 and a plurality of reference segments such as reference segment 508, The weighing segments and reference are covered with an Isolation foil or foils, such as isolation foil 502. Isolation foil 508 is made, for example, from aluminum.

As mentioned above, measuring the pressure in the reference segments and determining a difference measurement alleviates the effects of environmental condition on the pressure of the fluid in the weighing mattress. However, it is noted that employing a weighing mattress with a thermal coefficient of mm also alleviates the affects of the environmental conditions, A weighing mattress which exhibits thermal coefficient of zero may be achieved by employing materials and fluids of positive and negative thermal coefficients.

In typical weighing systems, it Is desirable to reference the sensor before performing a weight measurement. Referencing the weight sensors relates to associating a signal output from the sensor with a reference weight (e.g., the zero weight). Referencing the weigh! sensors alleviates errors in the sensor output signal (e.g. , due to changes temperature, or^■.drift in the sensor output signal).; Typically, referencing the sensors entail lifting the patient from the bed, referencing the sensors, and returning the patient to the bed. According to the disclosed technique, the sensors may be referenced without lifting the patient off the bed {re,, the patient remains lying on^' the mattress), by detaching the load of th patient from the -weight sensors. Referring hack to Figure 4A, reference senso 210 is referenced by completely deflating reference segments 220_{1 :} 22¾, 220₃, 220^ and inflating weighing segments 218-, , 2182, 218g, 218_¾ such that the patient, is detached from reference segments 220*, 22C½, 220₃ 220_¾ (i.e., the patient does not come into contact with reference segments 220_†l 22Q->, 220¾, .... 220,_¾ and does not apply weight thereon) and reference sensor 210 is referenced. Similarly, weight sensor 208 is referenced by completely deflating reference weighing segments 218 _; 218_2: 218₃, 218# and inflating segments 220- t, 220s. 220_s, ^'220M such that the patient is detached from weighing segments 218^ 218₂, 218₃, .... 2i¾ (i.e., the patient does not come into contact with weighing: segments 218_{1 t} 218₂, 218_3i 218^ and does not apply weight thereon) and weight sensor 208 is referenced.

Referencing the sensors by detaching the patient from the weight sensors (i.e., either the sensor themselves, or elements connected to the sensors such as the weighing and reference segments) , may be applied when th weight of the patient Is measured, for example, with load-cells. To that end, at least one vertical separator is placed under the mattress. The vertical separato detaches the mattress from the load-eelis such that no weight Is applied on the load-cells. The load-cell^'s- are referenced and vertical separato returns the mattress again on the load- ceils. The vertical separator may be one or more inflatable elements (e.g., a gas tube, an inflatable mattress), one or more hydraulic pistons, one or more pneumatic pistons one or more electric pistons and the like.

Reference is now made to Figures 10A, 10B and 10C, which are schematic illustrations of a weight scales system, generally referenced SS0:, constructed and operative in accordance with another embodiment of the disclosed technique, In general, weight scal system SOD includes a bed section. The ed section includes a plurality of load-cells 55¾_f 552₂, 552s, 652Λ, m 562g, a lower platform 554, an upper platform 558 and a vertical separator 558. In figures 10A-1GC. vertical separator is ^•exemplified as an Inflatable element Weigh scale system 500 further includes a pump 580, a controller 562, a user interface 563 and a memory 565. Load-cells 552_{1 (} 552_{2 :} 552₃. §S2₄, and 552₅ are positioned on lower platform 554 and optionally mechanically coupled thereto (e.g., either with glue, screws, or hoop-and-foo straps). Vertical separator 558 .Is placed on lower platform 554 but not on top of load-cells 552 , _t 552₂, 552₃, 552₄, and 552§. Upper platform 556 is placed above bad-cells BS2 _. 552_¾. 552_¾, 5524, and 552_δ. As a result, vertical separator 558 is positioned between lower platform 554 and upper platform 556. Up e platform 556 may further include aligning elements at the bottom side thereof, such as aligning element 588, for aligning upper platform 556 with load-cells 552;, 552₂, 552_3; 5524, and 552_5j such that load-cells 552 _: 552?, 552₃, 55¾_; and 562_s are positioned at the corresponding positions thereof under upper platform 586. Aligning elements such as alignment element. 568 may be embodied, for example, as alignment wedges. Also, upper platform 556 may he made of metal, wood, plastic or polycarbonate materials and may be embodied as a frame or a plate.

Pump 580 is coupled with controller 562 and fluidaily coupled with Inflatable element 558. Each one of load-cells 5S2_¾, 552; , 552s, 552 , and 552_s is coupled with controller 562. However, for the sake of clarity of Figures 10A- 0C only load-cells 552 and 552» are depleted as coupled with controller 582. Controller 585 Is- further coupled with user interface 563 and with memory 565. A mattress 584 may be placed on top upper platform 558 and a patient 568 ma lie down on top of mattress 564. Following is a description of the process of referencing load-ceils 552*, 552?, 552-x, 552,, and 552«. W¾h reference to Figure 10A, load-cells 552 -j , 5S2₂, 552₃, 552 , and 552 s are lo he referenced (i.e., associated with a referenced weight). To that end, controller 562 directs pum 560 to pump gas (e.g., air. carbon dioxide and the like) info vertical separator 558 from an gas supply (e.g.,, ambient air or a gas tank). Vertical separator 558 inflates and separates upper platform 656, along with mattress 564 and patient 566, from load-ceils 5S2-_t, 552- _» 552_3t 552₄. and 55 s (i.e., such thai upper platform 558 does not come into contact with load-ceils 552,, 552₂, 552_¾, 552-4, and 552_¾) and the weight associate with upper platform 556 (the tare weight and the weight of patient 588) is not applied on load-cells 552-: , §522, 552₃, 55 4_» and 5S2_S, In other words, vertical separator 558 detaches upper platform 556 and the load placed thereon from load-cells 5S2 _! 552_.2, 552₃, 552 , and 552_δ such that the weight associated with upper platform 556 is not applied on load-cells 552_{1 (} S52₂, 552₃, 552 _: and S2_$,

iih reference to Figure 108, vertical separator 55β has been Inflated and upper platform 558, along with mattress 584 and patient 586 are detached from toad-celts 552<_s 65 a, 5§2_S, 55¾, and 552_¾. Controlle 562 acquires measurements, from load-cells 5S2 . 652_2> 552_a> S52<<, and 55¾ and associated these measurements with a reference weigh, for example, the zero weight (i.e., referencing the load-cells).

With reference to Figure iOC, after load-cells 552 _t 552_¾, 5S2₃, 552,s, and 55¾ have been referenced, controller 562 directs pump 560 to pump gas out of vertical separator 558 (I.e., deflate vertical separator 558) until upper platform 556 is lowered on top of load-cells 5 2. , 552_¾ 552_¾ 552,}, and 552₅, along with mattress 564 and patient 568, until upper platform 556 re-attaches load-cells S52i, 5S2₃, 552_¾ 552_4i and 552§ suc that the weight associated with upper platform 558 fully applied on load-cells 55 ^ ·55¾-, 552₃₍. 552₄, and S52_s, In general, controller 562 said directs pump 560 fo operate the bed section, via vertical separator 558 in at least two modes, a referencing mode and a weighing mode. In the referencing mode, vertical separator 558 detaches upper platform 556 from load-cells 552_{1 s} 552_?, 552», 552 , and 552_$, thereby enabling the referencing of load-cells 552 552₂, 552_3! 552₄; and 552₅. in the weighing mo , vertical^' separator 558 re-attaches upper platform 556 with load-cells 552i, 552_2s 552_3! 552 , and ¾32_s, such the weight associated with upper platform 556 is fully applied on toad-cells 552, , 552_2i 552_¾ 552 _i and §52_s.

It is noted although five load-ceils are depicted in Figures 10A-10C, the number of load-cells is not limited thereto and may larger or smalle according to design consideration. Also, although only a single vertical separator is referred to in Figures 1_.QA and 1GB, the number of vertical separators is not limited- thereto and may larger according to design consideration, In general, each load-cell, each pair of load-ceils or each group of four load-cells may be connected fo a heaisfone bridge, In other words, the load-ceils ^'.may be connected to Wheatstone bridges in a quarter bridge, half bridge or full bridge configurations. The outputs of the Wheatstone bridges are sampled (e.g., with analog to digital converters} and summed (e.g.. by controller 582}.. Controller 582 presents the weight of the patient 588 to user via user interface 563.

When measuring the weight of a patient such as patient 566, the total weight of mattress 584 and upper platform 558, as well as of additional objects (e.g., pillows, blankets, sheets and the like), also referred to as tare weight, should be known. When measuring the weight of a patient, this tare weight is subtracted from the weight measured by the load-ceils. The tare weight is determined when the: patient is not located on the mattress. The ioad-ce!ls are referenced similar to as described above, prior to measuring the tare weight Alternatively, the weight of mattress 564. upper platform 556 and of other individual additional objects (e.g .. the weight of each pillow, the weight of each blanket) may be measured prior to use and stored in memory 565. A user can indicated, via user interface 562 the number of blankets and pillows placed on the bed. Furthermore, if for example, the patient requests a additional blanket or an additional blanket, the user updates the tare weight by indicating, via user interface 563, that a blanket or a pillow has been added.

Following i an example of a bed section according to a further embodiment of the disclosed technique. Reference is now made to Figures 1 1 A, 1 16 and 11C, which are schematic illustration of an exemplary bed section, general referenced 600, constructed and operative in accordance with a further embodiment of the disclosed technique. Figure 1 1A depicts an isometric view of bed section 600, Figure 1 1 B: depicts a top view of bed section 600 and Figure 1 C depicts a side view of bed section 600. Bed section 600 is located on a bed 602. Bed section 600 includes a lower platform 8Q4, an upper platform 606, a plurality of load-cells such as load-cell 608 and two vertical separators 610,! and 610_¾, In the example brought: forth in Figures 1 1A~1: :1 C, upper platform 606 embodied as a frame and may include load-ceils enclosures such as load-cell enclosure 612. Alternatively, . lower platform 604 includes- load-ceils enclosures. Also in the example brought: forth in Figures 11A-11 C, each one of vertical separators 610, and 6 ₂ is embodied as a gas tube.

In general a weight scale system such as described above in conjunction with Figures 10A-10C and 11A-11C includes at least one vertical separator. When embodied as an inflatable element, the vertical separator may exhibit a selected form such as a straight line, the form of the letter ⁴S', the form of a figure ^!8\ the form of the letter ΊΗΓ and the like- When^' a plurality of inflatable elements are employed, all the inflatable elements may be fluidaily coupled with a single pump.. Alternatively, each inflatable dement may be ftuidally coupled with a respective pump or each group of inflatable elements may be fluldaliy coupled with a respective pump. -Also, the lower piatform (e.g., lower platform. 554 - Figures 0A- 0C or lower platform 604 - Figures i lA-t l C) and the upper platform (e.g., upper platform 556 - Figures 11A-11C or upper platform 806 ~ Figures 10A-10C) may e partitioned into ^' cor es onding sections, such that the lower platform and the upper platform are foidable.

When detaching the upper platform from the load-ceils, the upper piatform may be raised above the load-cells or alternatively, the lower platform may be lowered. Reference is now made to Figures 12A and 128, which are a schematic illustration of an exemplary bed section, generally referenced 700, constructed and operative in accordance with another embodiment of the disclosed, technique. Bed section 700 is located on a bed 702. Bed 702 Includes bed .section supports 704₁ and 70% A mattress 716 is placed on top of upper platform 708. and a patient 718 may lies down o mattress 716, Bed section 700 Includes a lower platform 706, an upper platform 708, a plurality of load-cells 710 _Έ. 10^ and 710₃: and two vertical separators 71¾ and 12 . Load-cells 71% 7102 and ?10_3. are positioned on lower platform 708 and optionally mechanically coupled thereto. Upper platform 708 may include alignment elements such as alignment wedge 714. Vertical separators 712_¾ and 712 are mechanically coupled with bed section supports 704 _¾ and 704a respectively.

With reference to Figure 12A, upper platform 708 is supported by load-cells 710;, 710_¾ and 710_¾ such tha upper platform 708, mattress 564, and patient 568 apply their full weight on load-cells 710 710_;, and 71% With reference to Figure 12B, vertical separators lowered lowe platform 706 along with bad-cells 71Q_{1 s} 71% and 710_¾ such that upper platform 708 and load-cells 710 > 710_s and 7 G₃ are separated one from the other, upper platform 708. rests on bed- section supports 70 and 7.0 ₂, and no weight is applied o joad-cei-ls 7iQ_u 71G₂ and 710₃. Thereafter, the load-ceil can foe referenced and the vertical separators 712, and 71^'2₂ raise lower platform 706, long with load-cells 710_{S i} 71 ₂ and 710·_.;. such that the upper platform 70S and the load placed thereon apply their full weight on load-cells 710·;, 7i0_2: and 710¾.

As mentioned above . lower platform and the upper platform of a bed section of a weight scale system according to the disclosed technique are partitioned info corresponding sections, such that the lower platform and the upper platform are foldable. When employed for measuring the weight of a patient in a hospital bed, this enables the bed section fold when one of the bed sections is inclined. Nevertheless, weight scale system according to the disclosed technique can still determine the weight of the patient when one of the bed sections is Inclined. Reference is now made to Figures 13A and 13E1 Figure ISA is a schematic illustration of an exemplar bed section, general referenced 720, constructed and operative in accordance with a further embodiment of the disclosed technique. Figure 13B is a schematic illustration -of an exemplary weight sensor assembly, general referenced 732, constructed and operative in accordance with a further embodiment of the disclosed technique.

With reference to Figure 13A, bed section 720 is placed on a support 721 of bed 722. A mattress 724 is placed on top of bed section 720. A patient 724 may be lying: down on mattress 722. Bed section 720 includes a lower platform 728, an upper platform 730, and a plurality of weight sensor assemblies such as weight sensor assembly 732. Bed section 720 further includes at least one vertical separato (not shown in Figure 14 for the sake of clarity}. In Figure 14A, the segment of bed section 720 on which the upper body of patient 726 is located is inclined at an angle relative to support 721.

With reference to Figure 138, weight sensor assembly 732 Includes two weight Sensors,_: first weight sensor 734i (also referred to as "horizontal sensor"), second weight sensor 734-> (also referred to as 'Vertical sensor") and an L-shaped bracket 736 (i.e., a bracket where the bracket plates are connected perpendicularl one with respect to the other). L-shaped bracket 736 Includes two plates, first plate 737< and second plate 737₂, First plate 737, and second plate 737_a are perpendicular one with respect to the other. Figure †4B depicts a side view of L-shaped bracket 736, First weight sensor 734¾ is attached to lower frame 728 (i.e., either directly or sn-direcity via a sensors enclosure) and to the outer face of first plate 737<, such that first weight sensor 734₅ measures any force applied perpendicular to first plat .7%7-t (i.e., in the direction of arrow 820) Second weight sensor 734₃ Is attached to the inner face of second plate 737_?5 such that second weight senso 734a measures any force applied perpendicular to second plate 737₂ (i.e.. In the direction of arrow 822). L-shaped bracket 738 decomposes the force applied on the inclined segment of bed section 720 to the components thereof (i.e., the inclined segment of bed section 720),

Upper platform 730 Is positioned on top of second weight senso 73½, The weight of patient 7.26, lying down on matters 724, applies a force in the direction of arrow 738 (Le,, perpendicular to suppor 721 ), First weight sensor 734i measures the component in the direction of arrow 820. Second weight sensor 734₂ measures the component in the direction of arrow 822, The magnitud of the vector sum (i.e., the root of the sum of the squares) of these two measurements is the magnitude of the forc applied by patient 726 on sensor assembly 732, Sensor assemblies, such as weight sensor assembly 732 may also be connected to hesststone bridges in a quarter bridge, half bridge or full bridge configuration. When a plurality of sensor assemblies such as sensor assembly 732 are grouped (i.e... in groups of twos or fours), ail the horizontal sensors in the group are connected to one Wheaisfone bridge and all the vertical sensors are connected to another VVheatsfone bridqe. The output from each Wheaistone bridge is sampled and the magnitude of the vector sum of these outputs is determined.

Reference is now made to Figure 14 which is a schematic illustration of a weight scale^' system, generally reference 7S0. constructed and operative in accordance with another embodiment, of the disclosed technique. System 750 includes a controller 752, a bed section 754, a vertical separator actuator 758, a memory 758 and a user interface, Bed section 754 includes an upper platform 762, a vertical separator 784, weight sensor assemblies 768 and a lower platform 768, Bed section 754 may fee any one of the bed sections described above in conjunction with Figures 10A~1GC, 11A-11 C and 12A-128. Vertical separator ma fo an inflatable element e.g., inflatable element 556 - Figures 10A-10C) or inflatable element (e.g., inflatable element 810s and 610_£ ~ Figures 11 A- 11 ^'C), a hydraulic piston, a pneumatic piston, a electric piston, an electric scissors-jack and the like. Vertical separator actuator 758 corresponds to the type of vertical separator. For example, when vertical separator 764 is an inflatable element, vertical s parator actuator 756 is a gas pump. When vertical separator 784 is a hydraulic piston or a pneumatic piston, vertical separator actuator 756 is a hydraulic or pneumatic pump respectively. When vertical separator 764 is an electric piston or an electric scissors-jack, vertical separator actuator 756 is an electric motor. Each of weight, sensor assemblies 7B6 includes at least one weight sensors (e.g., load-cells 552†, 5522, 552_3i 552 _l and 5S2_S ·^■■· Figures 10A-10C, sensor assembly 732 - Figure 13B or a combination thereof). Memory 758 stores calibration data, and may also store information relating, to the weight of individual object typically placed on upper platform 782 (e.g., a mattress, a pillow, sheets, a blanket an the like). Memory 758 may further store, past measurements of the object. User interface 780 presents data to the user. For example, user interface presents the user with the weight of the object. User interface 780 may receive information relating to objects placed on upper platform 762 thus enabling to update the tare weight placed on upper platform 762,

Controller 752 is coupled with vertical separator actuator 756, with the weight sensors in weight sensor assemblies 766, with memory 758 and with user interface 780. Vertical separator actuator 756 is further coupled with vertica separator 764. In operation upper ^"platform 762 and the load placed thereon (i.e., the object to be measured and the tare weight) apply their full weight on weight sensor assemblies 766. Controller 75 acquires a measurement of the weight of the load applied on weight sensor assemblies 766 and subtracts the tare weight to determine the weight of the object (e.g,, a. patient in a hospital bed). When weight sensor assemblies 766 are employed for measuring the weight of an object positioned on an nclined surface, weight sensor assemblies include two weight sensors such as described above in conjunction with Figure 13Ά and 138, controller 752 determines the vector sum of each two weight sensors In weight sensor assemblies 786.

When referencing the weight sensor, controller 752 directs vertical separator actuator 756 to operate vertical separato 784 so as to detach upper platform 762, and the load placed thereon, from weight senso assemblies 768 such that no weight i applied on the weight sensors. described above, when detaching upper platform 762 from weight sensor assemblies 766, vertical separator 764 may raise upper platform 762 or lower lower platform 768. When upper platform 76.2 is detached from weight sensor assemblies 766, controller 752 references the weight sensors in the weight sensor assemblies 766 (I.e.,. controller 752 associates the measurements from weight sensor assemblies 766 with a reference weight). Thereafter, controlle 752 directs vertical separator actuator 758 to operate vertical separator 764 so as to re-attach upper platform 762 with weight sensors assemblies 766, such that the weight associated with upper platform 76:2 is fully applied on the weight sensor assemblies 786,

In genera}, controller 752 said vertical- separator actuator 756 to operate bed section 754, via vertical separator 784 in at least two modes, a referencing mode and a weighing mode. In the referencing mode, vertical separator 784 detaches upper platform 781 from weight sensor assemblies 768, thereby enabling the referencing of th weight sensors. In the weighing mode, vertical: separator 764 re-attaches upper platform 762 with weight sensor assemblies, such the weight associated with upper platform 762 (i;e,, the tare weight and the weight of the object) is fully applied on weight sensors.

Similar to as described above, when measuring the weight of an object, coniroiier 752 samples (e.g., with analog to digital converters) the measurements from the weight sensors or group of sensors (e.g., depending on the configuration of the VVheatstone bridges) and sums these measurements. Whe sensor assemblies 78 are similar to sensor assemblies 732 (Figures 13A and 138), controller 752 determines the magnitude of the vector sum of the measurements from horizontal sensors and the vertical^' sensor as described above In conjunction with Figures (I SA and 13B). Controller 752 presents the weight of the object to a user via user interface 760. Controller 752 may f urther be connected to a network, thereby transmitting the measured weight to a remote location. For example, when measuring the weight of a patient in a hospital bed, controller 752 transmits (e.g., via a network adapter) the weight to the nurse station. Alternative, controller 762 transmits the weight to a portable device (e,g., a smartphone, a tablet computer and the like). Furthermore, when -weight scale system 700 is employed to measure the weight of patient in a hospital bed, controller 752. may detect that the patient has left the bed (e.g., when the measured weight decreases at least at a predetermined rate arid drops below a threshold value for a predetermined !ime-perlod). Controiler 752 may than generat an alarm, for example, via user interface 760 or via the network. Also when weight scale system 700 is employed to measure the weight of patient in a hospital bed,_., weight scale system TOO may be employed to^' measure the liquid balance of a patient by entering (e.g. , via user interface 780) the weight of the liquids administered to the patient, and weighing the patient with and^■■without the waste collection bag. The difference between the weight of the patient with and without the waste collection bag results in the weight of the waste. The difference between the weight of the liquids administered to the patient and the weight of the waste is Indicative of the patient liquid balance.

Reference is now made to Figure IS, which is a schematic illustration of a method for referencing weight sensors in a bed section, operative in accordance with a further .embodiment of the disclosed technique. In procedure 800, the weight sensors are detached from the upper piatform of the bed section such that no load is appiseci on the weight: sensors. According to one alternative, the upper platform is raised above the weight sensors by a vertical separator. According to another alternative, the lower platform is lowered by the vertical separator. With reference to 13, controller 752 directs vertical separator actuator 756 to operate vertical separator 764 so as to detach upper platform 782, and the toad placed thereon from weight sensor assemblies 766,

in procedure 802. the weight sensors are referenced. When referencing the weight sensors, the measurement from the weight sensors is associated with a reference weight (e.g., the zero weight). Wit reference to Figure 13, controiler 752 references the weight sensor i weight sensor assemblies 766.

In procedures 804, the upper piatform is re-attached with the weight sensors such that the weight associated with the upper -platform (e.g., the weight of the- platform, th patient and of additional objects placed on the uppe platform) is fully applied on the weight sensors (i.e., either lower upper platform or raise lower platform). With reference to Figure 13, controller 752 directs controller 752 directs vertical separator actuator 756 to operate vertical separator 76 so as to re-attach upper platform 762 with weight sensors 786 such that upper platform 782 and the load plaeed thereon apply their full weight on weight sensors 766.

It will be appreciated by persons skilled in the art that the disciosed technique is not limited to what has been particularly shown anci described hereinabove. Rather the scope of the disclosed technique^' is defined only by the claims, which follow.

Claims

A weight scale system for measuring the weight of at least one ofo|ect_s the eight sca e system comprising:

a bed section including:

a Sower platform;

m upper platform; for bearing the weight of said at least one object:

a! least one weight sensor assembly Including ai least one weight sensor, said at least one weight sensor assembly being located on said lower platform, said at least one weight sensor being operable to measure weight applied thereon; and

at least one vertical separator, operable to detach said tipper platform from said at least one weight sensor assembly; at least on vertical separator actuator, coupled with said vertical separator, operable to operate said vertical separator; and a controller, coupled with said at ieast one weight sensor and with said vertical separator actuator, prior to referencing said at least one weight sensor, said controller directing said vertical separator actuator to operate said bed section in at least two modes;

a referencing mode in which said vertical separator detaches said uppe platform from said at least one weight sensor assembly, thereby enabling the referencing of said at Ieast one weight sensor; and

a weighing mode in which said vertical separator re-attaches said upper platform with said at Ieast one weight sensor assembly, such that the weigh associated with said upper platform is fully applied on said at Ieast one weight sensor. 2, The weight scale system according to claim 1 , wherein said vertical separator is at least one -inflatable element and said vertical separator actuator is at least om gas pump, fluid-ally coupled with said Inflatable element.

3 The weight system according to claim 2, wherein said vertical separator includes at least two air tubes.

4, The weight scale system according, to claim 2, wherein said upper platform includes alignment elements at the bottom side thereof, for aligning said upper platform with said at ast one weight sensor, such that said at least one weight sensor is positioned at the corresponding position thereof under said upper platform. §. The weight scale system according to claim 1, wherein said at least one weight sensor is a load-cell.

8. The weight scale system according to claim 1, wherein said vertical separator raises said upper platform so as to detach said upper latform said from said at least one weight sensor assembly.

7, The weight scale system according to claim 1, wherein said vertical separator lowers said tower platform so as to detach said upper platform said from said at least one weight sensor assembly.

5. The weight scale system according to claim 1 , wherein said bed section is positioned on a hospital bed, for measuring the weight of a patient lying down on said hospital bed: and wherein said vertical separator detaches said upper platform said from said at least one weight sensor assembly when said patient is lying down on said hospital bed.

The weight scaie system according to claim^' 1, wherein said at least one weight sensor assembly indud^s two weight sensors and an L-s a ped. bracket said L-shaped bracket includes- two plates perpendicular one with respect to the other, a first weight senso of said two weight sensors Is attached to said lower frame and to the outer face of a first plate, such that said first weight sensor measures a y force applied perpendicular to said first plate, a second weight sensor of said ^'two weight sensors is attached to the inner face of the second plate, such that said second weight sensor measures any force applied .perpendicular to said second plate, and

wherein the weight of the: object is applied on said second weight sensor.

The weight scale system according to claim 1 , wherein said at feast one weight sensor assembly includes a sensor enclosure,

A method for referencing at least one weight sensor in a weight scale system, the method comprising the procedures of:

detaching an upper platform of a bed section of a weight scale from said at least one weight sensor such that no weight is applied on said at least one weight sensor the bed section including a lowe platform, said upper platform for bearing the weight of at least one object, said a least one weight sensor being located on said lower platform and operable to measure weight applied thereon:

referencing said at least one weight sensor; and re-attaching the upper platform to said at least one weight sensor such that the upper platform and the load thereon apply their full weight on said at feast one weight sensor. 12. The method according to claim 11 , wherein said upper platform is lifted above said at least one weight sensor.

13. The method according, to claim 11 , wherein said tower platform is lowered so as to detach said upper platform from said at least one weight sensor.

14. The weight scale system according to claim 1 , wherein said a least one weight sensor is a load-cell. 15, The method according to claim i t, wherein said bed section is positioned on a hospital bed, for measuring the weight of a patient lying down on said hospital bed; and

wherein said detaching occurs when said patient is lying down on said hospital bed.