JP2011005030A - Device to determine if patient is in or out of bed and electrically-operated lifting bed equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device to detect and determine if a patient is in or out of the electrically-operated lifting bed without the need for any load measuring part such as a strain gauge or the like.SOLUTION: The in- or out-of-bed detecting device 1 includes: a motor driving part 10 to supply electric current to an electrically-driven motor M for operating a linear type actuator to lift the bed floor of the electrically-operated lifting bed; and an in- or out-of-bed detector 20. The in- or out-of-bed detector 20 supplies the motor driving part 10 with a command signal to supply electric current to the electrically-driven motor M for a short time of 30-150 msec. The in- or out-of-bed detector 20 analyzes the value of electric current supplied to the electrically-driven motor M, and based on the analysis results, determines if the patient is in or out of the electrically-operated lifting bed. This analysis employs the ratio of the maximum electric current to the integrated electric current value.

Description

  The present invention relates to a bed leaving determination device for determining whether a person is present on an electric lift bed in which a bed floor member is lifted or lowered by a linear actuator, or whether a person has left the electric lift bed, and The present invention relates to an electric elevating bed provided with this bed leaving device.

  There is an electric lift bed in which a bed floor member on which a mattress or mattress is installed is moved up and down by a linear actuator so that a person can easily stay on the bed or leave the bed. Are often used by older people and care recipients in hospitals and homes. In recent years, for the health management of elderly people and those who need care, or for detection of wrinkles, elderly people or care recipients are on the electric lifting bed used by elderly people or people who need care, or electric lifting There is a need for an out-of-bed detection device that determines whether the user is getting out of bed.

  A load from the bed floor member acts as an external force on the linear actuator of the linear actuator described above, and there are cases where an elderly person or the like is present on the bed and the elderly person from above the bed. When the person is getting out of bed, there is a change in the load corresponding to the weight of the elderly. By detecting this change in load, it is possible to determine whether an elderly person or a person requiring care is present on the electric lift bed, or whether it is off the electric lift bed. A bed moving detection device has been proposed in which a strain gauge is attached to the mechanism to detect a resistance change of the strain cage (Patent Document 1).

JP 2009-121666 A

  However, the presence / absence bed detection apparatus using a strain gauge is expensive because it requires a strain gauge as a load measurement component, an amplification circuit for detecting a resistance change of the strain gauge, and the like. In addition, in each of the bed-and-bed detection devices manufactured and sold, it is necessary to adjust the zero point in order to adjust the variation of the strain gauge before shipment, which further increases the cost.

  Therefore, without providing a separate load measurement component such as a strain gauge, a change in external force acting on the linear actuator is detected, and a person is on the electric lift bed or a person leaves the electric lift bed. It is an object of the present invention to provide a bed leaving detection device that determines whether a bed is moving, and an electric lift bed provided with the bed leaving detection device.

In order to solve the above-described problem, the bed detection apparatus according to the present invention has a person on the electric lift bed based on a current value of a current supplied to an electric motor that operates a linear actuator that raises and lowers the electric lift bed. In the presence / absence floor determination device for determining whether a person is getting out of bed from above the electric lift bed, and a current sensor for measuring a current value of a current supplied to the electric motor, and the electric motor A command unit that outputs a command signal for instructing to start the supply of current to the first time, and when the command signal is output from the command unit, a first time and a second time longer than the first time When time is measured and the first and second times are measured,
A timer unit that outputs first and second notification signals, respectively, and when the command signal is output from the command unit, starts supplying current to the electric motor, and the timer unit outputs the second notification signal. Is output, the motor drive circuit that stops the supply of current to the electric motor, and from the output of the command signal from the command unit to the output of the first notification signal from the timer unit A maximum current value detection unit that detects a maximum current value of a current detected by the current sensor and outputs a maximum current value signal; and the second notification signal after the first notification signal is output from the timer unit. Current value of the current detected by the current sensor until the current is output, a current value integration unit that outputs an integrated current integration value signal, and the maximum current value output from the maximum current value detection unit Trust And a current integrated value signal output from the current value integrating unit to determine whether a person is present on the electric lift bed or whether a person is leaving the electric lift bed. And a bed leaving part.

  The electric lifting bed of the present invention is supplied with the above-mentioned bed leaving detection device and the above-mentioned bed leaving signal output from the bed leaving detection device, and transmits that a person is getting off the floor from above the electric lifting bed. And is moved up and down by a linear actuator.

  The presence / absence floor detection device of the present invention can detect a change in external force acting on a linear actuator that raises and lowers an electric lift bed from a current value of a current supplied by an electric motor. Without being separately provided, it is possible to detect whether a person is on the bed or whether a person is leaving the bed.

It is a front view which shows the electric raising / lowering bed in the 1st Embodiment of this invention. It is a block diagram which shows the bed leaving apparatus in the 1st Embodiment of this invention. It is a figure which shows the process of the largest electric current value and electric current integrated value in the bed leaving apparatus in the 1st Embodiment of this invention. It is a flowchart which shows the process in the bed leaving apparatus in the 1st Embodiment of this invention. It is a figure which shows the electric current waveform detected with the bed leaving apparatus in the 1st Embodiment of this invention. It is a block diagram which shows the bed leaving apparatus in the 2nd Embodiment of this invention. It is a flowchart which shows the process in the bed leaving apparatus in the 1st Embodiment of this invention.

    Next, an explanation will be given based on FIG. 1 about the bed moving detection device 1 and the electric lifting bed 100 including the bed moving detection device 1 in the first embodiment of the present invention. The electric lifting bed 100 includes a bed frame 110, a bed floor member 111 on which a person H lies, a lifting device 120 that lifts and lowers the bed floor member 111 with respect to the bed frame 110, a bed leaving detection device 1, and a nurse as a transmission device. And a call device 130. The electric lift bed 100 is installed in a hospital room or a nursing facility, and may be used by elderly people or care recipients.

  The lifting device 120 includes an X-type link 121 that is slidably supported by both the bed frame 110 and the bed floor member 111, a linear type whose both ends are rotatably connected to the X-type link 121 and the bed floor member 111. An actuator 122 and a motor driving device 123 are included. As described above, both ends of the linear actuator 122 are pivotally supported by the X-type link 121 and the bed floor member 111, and an external force from the bed floor member 111 acts on the linear actuator 122.

  The linear actuator 122 includes an electric motor M and a linear motion mechanism 122 a that performs linear motion by rotation of an output shaft of the electric motor M by a control current supplied from the motor driving device 123. Then, the X-type link 121 having one end pivotally supported by the linear actuator 122 is expanded and contracted by the linear motion of the linear motion mechanism 122a, and the bed floor member 111 is moved by the expansion and contraction of the X-type link 121. Move up and down. In the present embodiment, the motor driving device 123 and the bed leaving device 1 are integrally formed, and various components are shared.

  The presence / absence floor detection apparatus 1 controls the current supplied to the electric motor M provided in the linear actuator 122, and the person H is present on the bed 100 from the current value of the current supplied to the electric motor M. It is determined whether the person is on the floor or the person H has left the bed 100. Then, a floor signal is output in the case of a flooring state, and a flooring signal is output in the case of a flooring state. The details of the bed leaving detection device 1 will be described later.

  The nurse call device 130 as a transmission device is connected to the bed leaving detection device 1 and is supplied with a bed signal or bed signal from the bed leaving detection device 1. The nurse call device 130 is connected to a monitoring device (not shown) installed in a nursing center of a hospital or a care center of a care facility by an electric communication line L. Is supplied to the monitoring device, and when the bed leaving signal is supplied, the monitoring device is notified of the bed leaving state. By these notifications, a nurse, a caregiver, or the like can confirm that an elderly person or a care recipient is present on the bed 100 or has left the bed 100.

  Next, the bed leaving detection apparatus 1 of this embodiment is demonstrated based on FIG. The bed leaving detection device 1 includes a motor driving unit 10 and a bed leaving detection unit 20. The motor drive unit 10 is connected to an AC power source P, and is connected to an AC-DC converter 11, an AC-DC converter 11, an electric motor M, and a bed leaving detection unit 20 that convert AC to DC, and a bed leaving detection unit 20. Is arranged between the motor drive circuit 12 that supplies the control current from the AC-DC converter 11 to the electric motor M and the motor drive circuit 12 and the ground G, and is supplied to the electric motor M. A current sensor 13 for measuring the current value of the control current is provided. The motor drive circuit 12 is shared by both the bed leaving device 1 and the motor drive device 123.

  The bed leaving unit 20 includes an electric command unit 21, a timer unit 22, an amplifier circuit 23, a current detecting unit 24, a maximum current value detecting unit 25, a current value integrating unit 26, and a bed leaving determining unit 30.

  The command unit 21 outputs a command signal that instructs to start supplying current to the electric motor M. The motor drive circuit 12 starts supplying a control current to the electric motor M when the command signal is output from the command unit 21.

  When the command signal is output from the command unit 21, the timer unit 22 starts measuring the first time ΔT1 and the second time ΔT2 that is longer than the first time ΔT1, and the first time ΔT1 is measured. Then, the first notification signal is output, and when the second time ΔT2 is measured, the second notification signal is output. In the present embodiment, the first time ΔT1 is set to 50 milliseconds, and the second time ΔT2 is set to 100 milliseconds. Note that the first and second times (ΔT1, ΔT2) are not limited to the above 50 and 100 milliseconds, and the first time ΔT1 may be 15 milliseconds to 75 milliseconds, and the second time ΔT2 may be not less than 30 milliseconds and not more than 150 milliseconds.

The amplifier circuit 23 is connected to the current sensor 13 and amplifies the current value of the current supplied to the electric motor M measured by the current sensor 13. The current detector 24 is connected to the amplifier circuit 23,
The current value amplified by the amplifier circuit 23 is detected, and a current value signal corresponding to this current value is output.

  The maximum current value detection unit 25 is connected to the command unit 21, the timer unit 22, and the current detection unit 24, and a command signal that commands the start of current supply to the electric motor M The current value supplied to the electric motor M is determined in advance based on the current value signal supplied from the current detection unit 24 until the first notification signal is supplied from the timer unit 22 until the first notification signal is supplied from the timer unit 22. Measured at the specified sampling period. Then, the maximum current value is sequentially updated from the measured current value, the maximum current value Imax is detected from the updated current value, and the maximum current value signal corresponding to the maximum current value is output.

  In the present embodiment, the time from when the command signal is supplied to when the first notification signal is supplied is set to 50 milliseconds, and the sampling period is set to 1 millisecond. The current value is measured 50 times, and the maximum current value is detected as the maximum current value Imax.

  The current value integration unit is connected to the timer unit 22 and the current detection unit 24, and is supplied from the current detection unit 24 until the second notification signal is output after the first notification signal is supplied from the timer unit 22. Based on the supplied current value signal, the current value supplied to the electric motor M is measured at a predetermined sampling period. Then, the measured current values are respectively integrated, and a current integrated value signal corresponding to the integrated current integrated value ΣI is output.

  In the present embodiment, the time from when the first notification signal is supplied until the second notification signal is supplied is set to 50 milliseconds, and the sampling period is set to 1 millisecond. Is 50. Then, the current value integrating unit 25 measures the current value 50 times, which is the number of integrations, and the 50 current values are integrated and detected as the current integrated value I.

  Based on FIG. 3, the maximum current value Imax and the integrated current value I will be described. In the figure, the vertical axis indicates the current value of the current supplied to the electric motor M based on the command signal from the command unit 21, and the horizontal axis indicates the number of times of sampling and the time.

  When a command signal is output from the command unit 21 at time T0, supply of current to the electric motor M is started, and the maximum current value detection unit 25 starts measuring current values and sequentially measures currents. Based on the value (Ii: i = 1 to 50), the current value that becomes the maximum sequentially is picked up and updated. In the figure, the current value measured at time Ta is measured as the maximum current value Imax, and a maximum current value signal corresponding to the maximum current value Imax is output.

  When the first notification signal is supplied to the current value integrating unit 26 at the time T1 when the first time ΔT1 has elapsed from the time T0, the current value integrating unit 26 starts measuring the current value, and starts from the time T1. The current values (Ii: i = 51 to 100) sequentially measured until time T2 when the time ΔT2 of 2 has elapsed are integrated. Then, a current integrated value signal corresponding to the integrated current integrated value ΣI is output. At time T2, when the second notification signal is output from the timer unit 22, the supply of current to the electric motor M is stopped.

The external force from the bed floor member 111 acts on the electric motor M linear actuator 122 that operates the linear actuator 122, and the external force changes depending on the presence or absence of the person H on the bed floor member 111. Generally, when the electric motor is driven in a high load state where a large torque acts on the rotating shaft, a current having a higher current value is supplied from the power source to the electric motor than when the electric motor is driven in a low load state. On the other hand, the current value of the inrush current, which is the current value immediately after the current is supplied to the electric motor, is substantially constant regardless of the magnitude of the torque acting on the rotating shaft.

  The bed leaving detection apparatus 1 utilizes the above properties. That is, the maximum current value immediately after the supply corresponding to the inrush current is detected by the maximum current detection unit 25, and the current integrated value that is the current amount of the current that varies depending on the presence or absence of the person H on the bed floor member 111 is represented by It is detected by the integrating unit 26. Then, using the values of the maximum current value and the integrated current value, it is determined whether the person is on the bed 100 where the person H is on the bed 100 or the person on the bed 100 who is not on the bed 100. To do.

  Hereinafter, the bed leaving determination unit 30 that is provided in the bed leaving detection device 1 and that determines the above bed state and bed leaving state will be described with reference to FIG. The presence / absence bed determination unit 30 includes a first memory 31, a determination reference value creation unit 32, and a first comparison unit 33, a maximum current value signal output from the maximum current value detection unit 25, and a current value integration unit 26. Is processed to determine whether a person is present on the electric lift bed 100 or whether a person is leaving the electric lift bed 100.

  A determination constant is stored in the first memory 31, and a determination constant signal corresponding to the determination constant is output from the first memory 31. The determination constant is a value obtained by multiplying a determination threshold less than 1 by the number of integrations that is the number of current values integrated by the current integration unit 26 (determination constant = determination threshold × number of integrations). In this embodiment, since the determination threshold is set to “0.64” and the integration constant is set to “50”, the determination constant obtained by multiplying them is “32 (= 0.64 × 50)”. Is set. The determination threshold may be less than 1 as described above, and desirably less than 0.7.

  The determination current value generation unit 32 is supplied with the maximum current value signal from the maximum current value detection unit 25, and is supplied with the determination constant signal from the first memory 31. Then, the determination current value generation unit 32 multiplies the maximum current value and the determination constant based on these signals to generate a determination current value (= maximum current value × determination constant), and the determination current value corresponding to the determination current value Output a signal.

  The first comparison unit 35 is supplied with the determination current value signal from the determination current value generation unit 32 and is supplied with the current integration value signal from the current value integration unit 26. The first comparison unit 35 compares the determination current value with the current integrated value based on these signals, and when it is determined that the current integrated value is equal to or greater than the determination current value, a person is placed on the bed 100. It is determined that the user is in the floor, and the floor signal is output. When it is determined that the integrated current value is less than the determination current value, it is determined that the person has left the bed 100 and a bed leaving signal is output.

  In the present embodiment, the bed or bed signal is set to be supplied to the nurse call device 130, and the bed or bed signal passes through the nurse call device 130 and is sent to a nursing center or a care facility of a hospital. It is transmitted to a monitoring device (not shown) where the center is installed. The nurse or caregiver can confirm whether the elderly person or the person requiring care is in the bed or in the bed leaving state based on the bed or bed leaving signal.

  Next, the signal processing in the bed leaving detection apparatus 1 of the present embodiment will be described based on FIG. When a command signal is output from the command unit 21 of the bed leaving unit 20, a series of processes is started. When the command signal is supplied to the motor drive circuit 12, supply of current from the AC-DC converter 11 to the electric motor M is started, and when the command signal is supplied to the timer unit 22, the timer unit 22 Measurement of the second time (ΔT1, ΔT2) is started (S1).

  The maximum current value of the current supplied to the electric motor M is detected by the maximum current detection unit 25 until the measurement time in the timer unit 22 reaches the first time ΔT1. Hereinafter, the processing will be described.

  When the supply of current to the electric motor M is started, the current detection unit 24 detects the current value of the current supplied to the electric motor M (S2), and the maximum current value detection unit 25 detects the current detection unit 24. The current value of the current supplied from is stored (S3). When it is determined that the time measured by the timer unit 22 does not become the first time ΔT1 (“no” in S4), the current value of the current supplied to the electric motor M is detected again. (S2) The maximum current value detection unit 25 compares the current value already stored with the current value of the current newly supplied from the current detection unit 24, and the current value of the newly supplied current is already stored. If the current value is larger than the current value, the current value of the newly supplied current is updated and stored as the maximum current value (S3).

  The above processes 2 and 3 are repeated until it is determined that the time measured by the timer unit 22 has reached the first time ΔT1 (“yes” in S4), and the maximum current detection unit 25 During this time ΔT1, the maximum current value of the current supplied to the electric motor M is stored.

  The current value of the current supplied to the electric motor M is integrated by the current value integration unit 26 until the time measured by the timer unit 22 exceeds the first time ΔT1 and reaches the second time ΔT2. Hereinafter, the processing will be described.

  The current detection unit 24 detects the current value of the current supplied to the electric motor M (S5), and the current value integration unit 26 stores the current value of the current supplied from the current detection unit 24 (S6). When it is determined that the time measured by the timer unit 22 does not become the first time ΔT2 (“no” in S7), the current value of the current supplied to the electric motor M is detected again. (S5) The current value integration unit 26 integrates the current value of the current newly supplied from the current detection unit 24 to the current value that has already been stored, and stores the integrated current value.

  The processes 5 and 6 are repeated until it is determined that the time measured by the timer unit 22 has reached the second time ΔT2 (“yes” in S7), and the current value integrating unit 26 The current value of the current supplied to the electric motor M is sequentially integrated until the time ΔT1 is exceeded and the second time ΔT2 is reached, and the integrated current integrated value is stored.

  When it is determined that the time measured by the timer unit 22 has reached the second time ΔT2 (“yes” in S7), the motor drive circuit 12 ends energization of the electric motor M, and the timer unit 22 Time measurement is terminated and reset (S8). Then, the presence / absence determination unit 30 determines whether the user is present or left. Hereinafter, the processing will be described.

  The determination current value generation unit 32 of the stay determination unit 30 generates a determination current value from the maximum current value signal supplied from the maximum current value detection unit 25 and the determination constant signal supplied from the first memory 31 ( S9). Then, the first comparison unit 33 compares the determination current value with the current integrated value (S10).

  As a result of the comparison in the first comparison unit 33, when it is determined that the current integrated value is smaller than the determination current value ("yes" in S10), the person H has left the bed 100. Is determined to output a bed leaving signal (S11). On the other hand, when it is determined that the integrated current value is equal to or greater than the determination current value (“no” in S10), it is determined that person H is present on bed 100 and the presence signal is output. (S12).

FIG. 5 shows a result of the experiment by the bed leaving detection apparatus 1. FIG. 4A shows a case where the load is not loaded on the bed floor member 111 (0 [kgf]), that is, when a person H is getting off the bed 100. 5 is a waveform of a current detected by the detection device 1. On the other hand, FIG. 5B shows a case where a load of 40 [kgf] is loaded on the bed floor member 111, that is, when a person H is present on the bed 100. It is a waveform of the electric current detected with the bed leaving apparatus.

  As shown in the figure, the maximum current value Imax is a substantially constant value in both the assumed bed leaving state and the assumed bed standing state. On the other hand, the current integrated value ■ I is larger than the assumed flooring state in the assumed bed leaving state, and in the assumed bed leaving state, the current integrated value ■ I is smaller than the judgment current value and becomes “0.89 times”. In the presence state, the integrated current value I is large with respect to the judgment current value and is “1.17 times”. As a result, the bed leaving detection device 1 determines that the current accumulated value ■ I is less than the judgment current value in the assumed bed leaving state, outputs a bed leaving signal, and in the assumed bed standing state, the current accumulated value ■ I is judged. It is determined that the current value is greater than or equal to the current value, and a bed signal is output.

  Next, the effect which the bed leaving detection apparatus 1 of this embodiment has is demonstrated. The presence / absence floor detection apparatus 1 is configured such that the person H is present on the bed 100 by the current value of the current supplied to the electric motor M that operates the linear actuator 122 that moves the bed floor member 111 of the bed 100 up and down. Or whether the person H is getting out of bed. Therefore, it is possible to detect the bed leaving state and the bed standing state without separately using a load measuring component such as a strain gauge.

  The bed leaving detection device 1 is a device that supplies a current to the electric motor M during the second time ΔT2 and detects the bed leaving state and the bed standing state based on the current value of the current. Since this second time ΔT2 is a very short time of 30 milliseconds to 150 milliseconds, the rotation angle of the rotating shaft provided in the electric motor M is very small. Therefore, the amount of operation of the linear actuator 122 that raises and lowers the bed floor member 111 is small, and even when the person H is present on the bed 100 when the presence / absence floor detection apparatus 1 is operating, the person H Does not feel that the bed floor member 111 is moving.

  Next, a bed leaving apparatus 200 according to a second embodiment of the present invention will be described. The bed leaving detection apparatus 200 of the second embodiment is different from the bed leaving detection apparatus 1 of the first embodiment only in the bed leaving determination unit 40, and the other parts are the same. Accordingly, only the configuration of the bed leaving determination unit 40 will be described based on FIG. 6, the process in the bed leaving determination unit 40 will be described based on FIG. 7, and description of other parts will be omitted.

  As shown in FIG. 6, the bed leaving determination unit 40 includes a second memory 41, a calculation unit 42, a third memory 43, and a second comparison unit 44. The second memory 41 stores “50”, which is the value of the number of integrations, and the second memory 41 outputs an integration number signal corresponding to the number of integrations. It should be noted that “50”, which is the value of the number of times of integration, is the same as the number of integrations set in the bed detection apparatus 1 of the first embodiment.

  The calculation unit 42 is supplied with the integration signal from the second memory 41, supplied with the maximum current value signal from the maximum current value detection unit 25, and supplied with the current integration value signal from the current value integration unit 26. Then, the calculation unit 42 calculates a determination value (= current integration value / (maximum current value) × number of integrations) obtained by dividing the current integration value by the maximum current value and the number of integrations. A determination value signal corresponding to the determination value is output.

  A determination threshold value is stored in the third memory 43, and a determination threshold signal corresponding to the determination threshold value is output from the third memory 43. Note that the determination threshold value of the present embodiment is “0.64”, which is the same as the determination threshold value set in the bed-separated bed detection device 1 of the first embodiment.

The second comparison unit 44 is supplied with a determination value signal from the calculation unit 42 and is supplied with a determination threshold signal from the third memory 43. Then, when it is determined that the determination value is less than the determination threshold based on the determination value signal and the determination threshold signal, it is determined that the person H has left the bed 100, and a bed leaving signal is output. On the other hand, if it is determined that the determination value is greater than or equal to the determination threshold, it is determined that the person H is present on the bed 100 and an in-bed signal is output.

  As shown in FIG. 7, the energization of the electric motor M is completed, and after the time measurement by the timer unit 22 is completed, the presence / absence determination processing by the presence determination unit 40 is performed (S101). To S104). First, the calculation unit 42 processes a determination value obtained by dividing the current integrated value by the maximum current value and the number of integrations (S101), and then the second comparison unit 44 sets the determination value and the determination threshold value. The size is determined (S102).

  When it is determined that the determination value is smaller than the determination threshold as a result of comparison by the second comparison unit 44 (“yes” in S102), it is determined that the person H is getting out of bed. A bed leaving signal is output (S11). On the other hand, if it is determined that the determination value is greater than or equal to the determination threshold (“no” in S10), it is determined that person H is present on bed 100 and an in-bed signal is output (S12). ).

DESCRIPTION OF SYMBOLS 1 Bed leaving detection apparatus 10 Motor drive part 11 AC-DC converter 12 Motor drive circuit 13 Current sensor 20 Bed leaving detection part 21 Command part 22 Timer part 23 Amplifier circuit 24 Current detection part 25 Maximum current value detection part 26 Current value integration part 30 bed leaving determination unit 31 first memory 32 determination current value creation unit 33 second comparison unit 40 bed leaving determination unit 41 second memory 42 calculation unit 43 third memory 44 second comparison unit 100 electric lift bed 110 Bed frame 111 Bed floor member 120 Lifting device 121 X-type link 122 Linear actuator 122a Linear motion device 123 Motor drive device 130 Nurse call device 200 Bed leaving detection device M Electric motor H Person P Power source

Claims (8)

Depending on the current value of the current supplied to the electric motor that operates the linear actuator that raises and lowers the electric lift bed, a person is present on the electric lift bed or the person leaves the electric lift bed. In the presence / absence floor discrimination device that judges whether
A current sensor for measuring a current value of a current supplied to the electric motor;
A command unit that outputs a command signal for commanding to start the supply of current to the electric motor;
When the command signal is output from the command unit, a first time and a second time longer than the first time are measured, and when the first and second times are measured, A timer unit for outputting the first and second notification signals;
When the command signal is output from the command unit, supply of current to the electric motor is started, and when the second notification signal is output from the timer unit, supply of current to the electric motor is stopped. A motor drive circuit;
The maximum current value of the current detected by the current sensor is detected from when the command signal is output from the command unit to when the first notification signal is output from the timer unit, and the maximum current value signal is output. A maximum current value detecting unit,
The current value of the current detected by the current sensor is integrated after the first notification signal is output from the timer unit until the second notification signal is output, and an integrated current integrated value signal is output. Current value integrating unit
Process the maximum current value signal output from the maximum current value detection unit and the current integration value signal output from the current value integration unit, whether a person is present on the electric lift bed, A bed leaving determination device comprising a bed leaving determination unit that determines whether a person is getting out of bed from the electric lift bed.   2. The bed leaving apparatus according to claim 1, wherein the second time measured by the timer unit is not less than 30 milliseconds and not more than 150 milliseconds.   The current value integration unit is detected by the current sensor at a predetermined number of integrations from when the first notification signal is output from the timer unit to when the second notification signal is output. The bed leaving detection apparatus according to claim 2, wherein current values of currents are integrated.   The bed leaving / separating unit compares a determination current value obtained by multiplying the maximum current value by the first integration number and a determination threshold value less than 1, and the current integration value, and the current integration value is the determination current value. If it is less than that, it is determined that a person is getting out of bed from above the electric lift bed, and if the current integrated value is equal to or greater than the determination current value, a person is present on the electric lift bed. It is judged that he / she is present. The presence / absence bed detection apparatus of Claim 3 characterized by the above-mentioned.   The bed leaving / separating unit compares the determination value obtained by dividing the current integrated value by the maximum current value and the number of integrations, and the determination threshold, and the determination value is less than the determination threshold. Determines that a person is getting out of bed from above the electric lift bed, and if the determination value is equal to or greater than the determination threshold, determines that a person is present on the electric lift bed. The away bed detecting apparatus according to claim 3.   6. The bed leaving position according to any one of claims 1 to 5, wherein the bed leaving determination section outputs a bed leaving signal when it is determined that a person has left the floor from the electric lift bed. Detection device. A bed leaving detection device according to claim 6, and a sending device that is supplied with the bed leaving signal output from the bed leaving detection device and transmits that a person is getting out of bed from the electric lift bed. An electric lift bed that is moved up and down by a linear actuator.   The electric lifting bed according to claim 7, wherein the transmission device is a nurse call device.

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