JP7505692B2 - Electric bed - Google Patents

Description

The present invention relates to an electric bed equipped with an actuator.

Conventionally, there are known electric beds that can change the height of the bottom supporting the user's body by using the driving force of an actuator, or change the angle of the bottom to raise the back or legs. There are also known electric beds that prevent the human body or foreign objects from becoming caught between the bottom and the frame when the bottom is lowered (see, for example, Patent Document 1).

The electric bed described in Patent Document 1 is equipped with a microcontroller that detects the presence or absence of entrapment by reading from a memory unit the basic motion profile data corresponding to the current motion profile data at a predetermined movement position of the bed movable part calculated by a calculation unit and comparing it with a predetermined inclination.

JP 2009-247426 A

However, the electric bed described in Patent Document 1 requires an ammeter that detects the current flowing through the actuator, a memory unit that stores basic motion profile data that is determined in advance from the current flowing through the actuator in an unloaded state, and a microcontroller that calculates the current motion profile data at a predetermined moving position of the bed movable part. Therefore, there is a need to simplify the configuration for preventing entrapment.

The object of the present invention is to provide an electric bed that can easily reduce the risk of problems caused by entrapment.

The electric bed of the present invention comprises a bottom, an actuator that changes the posture or height of the bottom, a receiving member that receives a downward load of the bottom at the lower limit position of the movable range of the bottom, an operation unit that receives operation instructions from a user, a control unit that controls the operation of the actuator in accordance with the operation instructions received by the operation unit, and a prohibition mechanism that prohibits a downward movement of the actuator to change the posture or height of the bottom downward when the load applied to the actuator does not meet a predetermined standard load , the actuator comprises a motor, an extendable telescopic rod connected to the bottom, and a gear mechanism that extends and retracts the telescopic rod by the rotational driving force of the motor, the downward movement occurs when the telescopic rod contracts, and the upward movement occurs to change the posture or lift the bottom upward, the prohibition mechanism is a ratchet mechanism that prohibits the downward movement by rotating the gear mechanism when the load in the direction of contracting the telescopic rod does not meet the standard load.

According to this configuration, since the actuator changes the attitude or height of the bottom, the load of the bottom is normally applied to the actuator. However, if pinching occurs in the bottom during the process of moving the bottom downward, the load is applied to the pinched human body or object, and the load applied to the actuator decreases. Then, when the load applied to the actuator falls below the reference load, the prohibition mechanism prohibits the bottom from moving downward, reducing the risk that the driving force of the actuator will act as a pinching force. Therefore, it is easy to reduce the risk of problems caused by pinching. Also, since the ratchet mechanism functions as a prohibition mechanism, it is easy to configure the prohibition mechanism.

Furthermore, it is preferable that, during a descent period in which an operation instruction for the downward movement is accepted by the operation unit, if the downward movement of the actuator is prohibited and the bottom is located above the lower limit position, the control unit causes the actuator to perform an upward movement to change the position or raise the bottom upward, and, during the descent period, if the downward movement of the actuator is prohibited and the bottom is located at the lower limit position, the control unit does not cause the actuator to perform the upward movement.

When downward movement of the actuator is prohibited and the bottom is located above the lowest position, it is believed that pinching may have occurred. In this case, the bottom can be changed in position or raised upward to release the pinching, improving safety. On the other hand, when the bottom is located at the lowest position, the load of the bottom is received by the receiving member, and when the load applied to the actuator falls below the reference load, downward movement of the actuator is prohibited even though pinching has not occurred. In this case, if the bottom is changed in position or raised upward, the bottom cannot be maintained at the lowest position. Therefore, when downward movement of the actuator is prohibited and the bottom is located at the lowest position, the bottom can be maintained at the lowest position by not causing the actuator to perform upward movement.

An electric bed with this configuration makes it easy to reduce the risk of problems caused by entrapment.

1 is a perspective view showing a configuration of an electric bed according to an embodiment of the present invention; 2 is a perspective view showing a state in which the lifting frame of the electric bed shown in FIG. 1 has been raised and the bottom, headboard, and footboard have been removed. FIG. FIG. 3 is a front view of the electric bed shown in FIG. 2 . FIG. 2 is a front view of the electric bed shown in FIG. 2 is a block diagram showing an example of an electrical configuration of the electric bed shown in FIG. 1 . FIG. 2 is an external view showing an example of a hand switch. 2 is a flowchart showing an example of the operation of the electric bed shown in FIG.

The following describes an embodiment of the present invention with reference to the drawings. Components with the same reference numerals in each drawing are the same, and their description will be omitted. In this specification, the direction of the electric bed 1 is indicated by the arrows in each drawing. Figure 1 is a perspective view showing the configuration of an electric bed 1 according to one embodiment of the present invention.

As shown in FIG. 1, the electric bed 1 is formed in a generally rectangular shape with the longitudinal direction in the front-to-rear direction in a plan view. The electric bed 1 mainly comprises a base unit 2 placed on the floor, a lift frame 3 connected to the base unit 2 so that it can be raised and lowered, a bottom 4 attached to the upper surface of the lift frame 3, a headboard 51 attached to the front end of the lift frame 3, and a footboard 52 attached to the rear end of the lift frame 3.

The bottom 4 includes a head bottom 41, a back bottom 42, a seat bottom 43, a knee bottom 44, and a leg bottom 45. The head bottom 41 is positioned to support the user's head, the back bottom 42 is positioned to support the user's back, the seat bottom 43 is positioned to support the user's waist, the knee bottom 44 is positioned to support the user's knees, and the leg bottom 45 is positioned to support the user's legs.

A user of the electric bed 1 uses the electric bed 1 by placing a mattress (not shown) on the top surface of the bottom 4 and lying on the mattress with the head at the front and the feet at the back.

Figure 2 is a perspective view showing the state in which the lifting frame 3 of the electric bed 1 shown in Figure 1 has been raised and the bottom 4, headboard 51, and footboard 52 have been removed. The electric bed 1 is equipped with actuators A1, A2, A3, and A4, and a control box C that controls the driving of these actuators. The actuators A1, A2, A3, and A4 are equipped with an extension rod R and a drive unit M that includes a motor and gear mechanism for extending and retracting the extension rod R.

The base unit 2 is a base that directly or indirectly supports all the components of the electric bed 1, and is formed in a rectangular shape with its longitudinal direction in the front-to-rear direction in a plan view. As shown in Figure 2, the base unit 2 has support frames 21, 21 on the left and right, each of which has an axial direction in the front-to-rear direction.

A leg base 22 that is placed on the floor surface is attached to both the front and rear ends of each of the support frames 21, 21. A support pillar 23 is placed at the front between the support frames 21, 21, and a support pillar 24 is placed at the rear in the left-right direction. This connects the support frames 21, 21, and the support frames 21, 21 and the support pillars 23, 24 form the base unit 2 as a sturdy frame.

In addition, a support pillar 25 that can slide in the front-rear direction is stretched between the support frames 21, 21 in the left-right direction in the area between support pillar 23 and support pillar 24. Rollers (not shown) are attached to both ends of the support pillar 25. The rollers on both ends of the support pillar 25 are guided by guide members 211 provided on the inside of the support frames 21, 21, allowing the support pillar 25 to slide in the front-rear direction.

The lifting frame 3 is roughly a rectangular frame body with a longitudinal direction in a front-to-rear direction in a plan view. The lifting frame 3 is connected to the base unit 2 so that it can be raised and lowered by a pair of left and right X-shaped link mechanisms 6. The X-shaped link mechanism 6 is configured by links 61 and 62 of the same length that are connected to each other so that they can rotate around an axis 63 that extends left and right at approximately the center.

The lower ends of the pair of links 61 are connected to the support column 23 so as to be swingable around an axis extending in the left-right direction. Rollers (not shown) are attached to the upper ends of the pair of links 61. The rollers of the pair of links 61 are guided by guide members 31, 31 attached to the lifting frame 3, so that the upper ends of the pair of links 61 are connected to the lifting frame 3 so as to be slidable in the front-rear direction.

The lower ends of the pair of links 62 are connected to the support columns 25. The upper ends of the pair of links 62 are connected to the lifting frame 3 so as to be swingable about an axis extending in the left-right direction. A connecting rod 64 is suspended between the pair of links 61 at a position above the axis 63.

A connecting rod 27 is stretched between the support frames 21, 21. The drive unit M of the actuator A1 is swingably connected to the approximate center of the connecting rod 27. A bracket 65 extending in the radial direction is attached to the approximate center of the connecting rod 64. The tip of the telescopic rod R of the actuator A1 is swingably connected to the tip of the bracket 65 around an axis extending in the left-right direction.

As a result, when the telescopic rod R of the actuator A1 extends, the X-shaped link mechanism 6 extends in the vertical direction and the lifting frame 3 rises, and when the telescopic rod R of the actuator A1 contracts, the X-shaped link mechanism 6 contracts in the vertical direction and the lifting frame 3 descends.

Figure 3 is a front view of the electric bed 1 shown in Figure 2. Figure 3 shows the state in which the bottom 4 is attached. A receiving member 66 is attached to the underside of the links 61, 62 of the X-shaped link mechanism 6, above the shaft 63. The receiving member 66 protrudes in the left-right direction, and when the X-shaped link mechanism 6 contracts, the receiving member 66 of the link 61 interferes with the link 62, and the receiving member 66 of the link 62 interferes with the link 61. The receiving member 66 is made of an elastic member such as rubber.

Figure 4 is a front view of the electric bed 1 shown in Figure 1. When the X-shaped link mechanism 6 contracts vertically and the lifting frame 3 descends, the receiving member 66 is pinched between the links 61 and 62, preventing the X-shaped link mechanism 6 from contracting any further and preventing the lifting frame 3 from descending. The position of the bottom 4 at this time is the lower limit of the movable range of the bottom 4 height. At this time, the load of the bottom 4 is supported by the receiving member 66.

Connected to the lifting frame 3 are a movable frame 411 that supports the head bottom 41, a movable frame 421 that supports the back bottom 42, a movable frame 441 that supports the knee bottom 44, and a movable frame 451 that supports the leg bottom 45. Between the movable frame 421 and the movable frame 441, the seat bottom 43 is fixedly attached to the lifting frame 3.

The movable frame 421 is connected to the lift frame 3 so as to be swingable about an axis extending in the left-right direction with its rear end as a fulcrum. The drive unit M of the actuator A2 is connected to the lift frame 3 so as to be swingable about an axis extending in the left-right direction. The tip of the telescopic rod R of the actuator A2 is connected to the movable frame 421 via a link mechanism 422.

The front end of the movable frame 421 and the rear end of the movable frame 411 are connected by a hinge 412 so as to be swingable about an axis extending in the left-right direction. The drive unit M of the actuator A3 is connected to the movable frame 421 so as to be swingable about an axis extending in the left-right direction. The tip of the telescopic rod R of the actuator A3 is connected to the movable frame 411 via a bracket 413.

As a result, when the telescopic rod R of actuator A2 extends, the movable frame 421 rotates to stand up and changes its position upward, and the movable frame 411 and actuator A3 move upward in conjunction with the change in position of the movable frame 421. When the telescopic rod R of actuator A2 contracts, the movable frame 421 rotates to fall down and changes its position downward, and the movable frame 411 and actuator A3 move downward in conjunction with the change in position of the movable frame 421.

The back bottom 42 is attached to the movable frame 421, and the head bottom 41 is attached to the movable frame 411. When the telescopic rod R of the actuator A2 extends, the head bottom 41 and the back bottom 42 rise upward in unison, and when the telescopic rod R of the actuator A2 contracts, the head bottom 41 and the back bottom 42 fall downward in unison.

When the back bottom 42 changes its position downward and becomes horizontal, the front end of the movable frame 421 or the link mechanism 422, etc. interferes with the lifting frame 3, and the back bottom 42 cannot change its position downward any further. The position of the back bottom 42 at this time is the lower limit of the movable range of the position of the back bottom 42. At this time, the load of the back bottom 42 and head bottom 41 is received by the lifting frame 3. The lifting frame 3 corresponds to an example of a support member for the back bottom 42.

When the telescopic rod R of the actuator A3 extends, the movable frame 411 changes its position upward, and the head bottom 41 rises. When the telescopic rod R of the actuator A3 contracts, the movable frame 411 changes its position downward, and the head bottom 41 becomes closer to being flat against the back bottom 42.

The movable range of the hinge 412 is limited to the position where the movable frame 411 and the movable frame 421 are flat, i.e., the flat position where the head bottom 41 and the back bottom 42 are flat. The hinge 412 bends in a direction where the bottom angle formed by the head bottom 41 and the back bottom 42 on the upper side becomes smaller than the flat position, but the hinge 412 is locked so that it cannot bend in a direction where the bottom angle becomes larger than the flat position.

When the head bottom 41 and back bottom 42 are in a flat position and the hinge 412 is locked, the position of the head bottom 41 at this time becomes the lower limit position of the movable range of the position of the head bottom 41. At this time, the load of the head bottom 41 is received by the hinge 412. The hinge 412 corresponds to an example of a receiving member for the head bottom 41.

The movable frame 441 is connected to the lifting frame 3 so as to be swingable around an axis extending in the left-right direction with its front end as a fulcrum. The rear end of the movable frame 441 is connected to the front end of the movable frame 451 by a hinge 442 so as to be swingable around an axis extending in the left-right direction. The drive unit M of the actuator A4 is connected to the lifting frame 3 so as to be swingable around an axis extending in the left-right direction. The tip of the telescopic rod R of the actuator A4 is connected to the movable frame 441 via a link mechanism 443.

As a result, when the telescopic rod R of actuator A4 extends, the movable frame 441 rotates to stand up and changes its position upward, and the front end of the movable frame 451 rises in conjunction with the change in position of the movable frame 441. On the other hand, when the telescopic rod R of actuator A4 contracts, the movable frame 441 rotates to approach horizontal and changes its position downward, and the front end of the movable frame 451 descends in conjunction with the change in position of the movable frame 441.

The knee bottom 44 is attached to the movable frame 441, and the leg bottom 45 is attached to the movable frame 451. When the telescopic rod R of the actuator A4 extends, the knee bottom 44 and the leg bottom 45 rise up in a mountain shape with the hinge 442 at the top, and when the telescopic rod R of the actuator A4 contracts, the hinge 442 descends, and the knee bottom 44 and the leg bottom 45 approach horizontal.

When the hinge 442 descends and the knee bottom 44 and leg bottom 45 change position downward to become horizontal, the rear end of the movable frame 441, the front end of the movable frame 451, or the hinge 442 interferes with the lifting frame 3, and the knee bottom 44 and leg bottom 45 cannot change position downward any further. The position of the knee bottom 44 and leg bottom 45 at this time is the lower limit position of the movable range of the position of the knee bottom 44 and leg bottom 45. At this time, the load of the knee bottom 44 and leg bottom 45 is received by the lifting frame 3. The lifting frame 3 corresponds to an example of a support member for the knee bottom 44 and leg bottom 45.

Hereinafter, the operation of raising the bottom 4 by the actuator A1 and the operation of changing the position of the head bottom 41, back bottom 42, knee bottom 44, and leg bottom 45 upward by the actuators A2, A3, and A4 will be collectively referred to as the upward operation, and the operation of lowering the bottom 4 by the actuator A1 and the operation of changing the position of the head bottom 41, back bottom 42, knee bottom 44, and leg bottom 45 downward by the actuators A2, A3, and A4 will be collectively referred to as the downward operation.

Figure 5 is a block diagram showing an example of the electrical configuration of the electric bed 1 shown in Figure 1. As shown in Figure 5, the electric bed 1 is equipped with actuators A1, A2, A3, A4, control modules A1C, A2C, A3C, A4C, a hand switch 8, and a control unit 7. Hereinafter, the actuators A1, A2, A3, A4 will be collectively referred to as actuator A, and the control modules A1C, A2C, A3C, A4C will be collectively referred to as control module AC.

Actuators A1, A2, A3, and A4 are connected to the control unit 7 via control modules A1C, A2C, A3C, and A4C. Control module AC expands and contracts actuator A in response to a control signal from the control unit 7.

The telescopic rod R of the actuator A is, for example, a spline shaft. The gear mechanism (not shown) of the actuator A rotates the telescopic rod R around its axis using the rotational driving force of the motor, thereby telescopically extending the telescopic rod R.

The actuator A is equipped with a ratchet mechanism (ratchet wheel) that inhibits downward movement by causing the above-mentioned gear mechanism to spin freely when the load in the direction of contracting the telescopic rod R does not meet a predetermined reference load. Such a ratchet mechanism is an example of a prohibition mechanism.

Although an example has been shown in which actuator A has a built-in ratchet mechanism, the ratchet mechanism (prohibition mechanism) may be provided outside actuator A.

The actuator A also includes a rotation detection sensor (not shown) that detects the rotation of the telescopic rod R. When the rotation detection sensor detects the rotation of the telescopic rod R, it outputs a signal indicating the rotation to the control module AC. A Hall element, for example, can be used as the rotation detection sensor. For example, the rotation of the telescopic rod R can be detected by attaching a magnet to a predetermined position on the outer periphery of the telescopic rod R and detecting the magnetic force of the magnet using the Hall element.

The control module AC calculates the extension length of the telescopic rod R, i.e., the stroke position, based on the signal indicating the rotation of the telescopic rod R output from the actuator A, and outputs a signal indicating the stroke position to the control unit 7. The control module AC also detects that the gear mechanism is spinning freely due to the ratchet mechanism and downward movement is prohibited, and outputs a signal indicating that downward movement is prohibited to the control unit 7.

For example, if actuator A no longer outputs a signal indicating rotation of telescopic rod R during a period in which control signal for downward movement to retract telescopic rod R is being output from control module AC to actuator A, control module AC can determine that downward movement is prohibited.

As an actuator A having the above-mentioned functions, for example, a linear actuator LA40 manufactured by LINAK can be used, and as a control module AC having the above-mentioned functions, for example, a control box C061 manufactured by LINAK can be used.

The actuator A only needs to be equipped with a prohibition mechanism that prohibits downward movement when the load in the direction of contracting the telescopic rod R does not meet a predetermined reference load, and the actuator A is not limited to a LINAK linear actuator, and the prohibition mechanism is not limited to a ratchet mechanism.

In addition, the control module AC is not limited to a LINAK control box, and the function of the control module AC may be provided by the actuator A or the control unit 7.

Figure 6 is an external view showing an example of the hand switch 8. The hand switch 8 includes a height lowering button 80D, a height raising button 80U, a head lowering button 81D, a head raising button 81U, a back lowering button 82D, a back raising button 82U, a foot lowering button 83D, a foot raising button 83U, a power switch 86, and a display unit 87.

The display unit 87 is, for example, a liquid crystal display, and displays the height and position of each bottom 4. The hand switch 8 is an operation unit that accepts operation instructions from the user. The hand switch 8 outputs a signal indicating the accepted instruction to the control unit 7.

The height lowering button 80D accepts an instruction to move the entire bottom 4 downward, and the height raising button 80U accepts an instruction to move the entire bottom 4 upward. The head lowering button 81D and back lowering button 82D accept an instruction to move the head bottom 41 and back bottom 42 downward, respectively. The head raising button 81U and back raising button 82U accept an instruction to move the head bottom 41 and back bottom 42 upward, respectively. The foot lowering button 83D accepts an instruction to move the knee bottom 44 and leg bottom 45 downward. The foot raising button 83U accepts an instruction to move the knee bottom 44 and leg bottom 45 upward.

The control unit 7 is housed in a control box C. The control unit 7 is configured with, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a RAM (Random Access Memory) that temporarily stores data, a non-volatile storage unit that stores predetermined control programs, etc., and peripheral circuits thereof.

The control unit 7 controls the operation of the actuator A in response to the operation instructions received by the hand switch 8.

In addition, during the descent period during which the operation instruction for the downward movement is accepted by the hand switch 8, when the bottom 4 is located above the lower limit position and the downward movement of the actuator A is prohibited, the control unit 7 causes the actuator A to perform the upward movement.

In addition, during the descent period during which the operation instruction for the downward movement is being accepted by the hand switch 8, if the bottom 4 is located at the lowest position and the downward movement of the actuator A is prohibited, the control unit 7 continues to instruct the actuator A to perform the downward movement.

Next, the operation of the motorized bed 1 configured as described above will be described. FIG. 7 is a flow chart showing an example of the operation of the motorized bed 1 shown in FIG. 1. Below, an example of the operation of lowering the bottom 4 from a state in which the lifting frame 3 has been raised and the bottom 4 is in a high position as shown in FIG. 3 will be described.

First, when the user presses the height reduction button 80D, the hand switch 8 receives an instruction to move the entire bottom 4 downward (step S1), and the hand switch 8 outputs an instruction to move the entire bottom 4 downward to the control unit 7. The following description will be given assuming that the height reduction button 80D is kept pressed.

Next, the control unit 7 instructs the actuator A1, which corresponds to the overall height of the bottom 4, to move downward via the control module A1C, thereby contracting the extendable rod R (step S2). Note that the control unit 7 stops the operation of the actuator A when the button is no longer pressed.

When the telescopic rod R contracts and the X-shaped link mechanism 6 contracts, the bottom 4 descends together with the lifting frame 3, and the downward movement is performed. While the downward movement is being performed, the control unit 7 monitors a signal from the control module A1C indicating that the downward movement is prohibited (step S3), and if the downward movement is not prohibited (NO in step S3), the downward movement by the actuator A1 continues (steps S2, S3).

On the other hand, when the ratchet mechanism causes the gear mechanism of actuator A1 to spin freely and the downward movement of actuator A1 is prohibited, the control module A1C detects that the downward movement is prohibited, and outputs a signal indicating that the downward movement is prohibited to the control unit 7 (YES in step S3).

Then, the control unit 7 checks whether the bottom 4 is above the lower limit position by referring to the signal indicating the stroke position of the telescopic rod R of the actuator A1 from the control module A1C (step S4). If the bottom 4 is above the lower limit position (YES in step S4), there is a possibility that a human body or a foreign object may have been caught under the lifting frame 3 during the descent process.

If a human body or foreign object becomes trapped under the lifting frame 3 during the descent process, the weight of the lifting frame 3 etc. is applied to the trapped human body or foreign object. When the weight of the lifting frame 3 etc. is applied to the trapped human body or foreign object, the load on the telescopic rod R of the actuator A1 decreases. Then, when the load on the telescopic rod R falls below the reference load, the ratchet mechanism causes the gear mechanism of the actuator A1 to spin freely, prohibiting the actuator A1 from moving downward.

This reduces the risk of the driving force of the actuator A1 being applied to a human body or foreign object trapped under the lifting frame 3, improving safety. Therefore, with the electric bed 1, it is easy to reduce the risk of problems caused by entrapment.

At this time, when the downward movement of actuator A1 is prohibited by the ratchet mechanism, the control module A1C detects that the downward movement is prohibited, and a signal indicating that the downward movement is prohibited is output from the control module A1C to the control unit 7 (YES in step S3). Therefore, if the downward movement is prohibited (YES in step S3) and the bottom 4 is above the lower limit position (YES in step S4), there is a possibility that a human body or a foreign object may have been caught under the lifting frame 3 during the descent process.

Therefore, if the bottom 4 is above the lower limit position (YES in step S4), the control unit 7 causes the actuator A1 to perform an upward movement and raise the lifting frame 3 (step S5).

As a result, even if a human body or foreign object becomes trapped under the lifting frame 3, the trapped human body or foreign object is released, further improving safety.

On the other hand, if the bottom 4 is located at the lowest position in step S4 (NO in step S4), the control unit 7 repeats steps S2 to S4. At this time, the ratchet mechanism causes the gear mechanism of actuator A1 to rotate freely, prohibiting the downward movement of actuator A1, and maintaining the bottom 4 at the lowest position.

Specifically, as shown in FIG. 4, when the height of the bottom 4 reaches the lower limit of the movable range, the receiving members 66 of the links 61, 62 interfere with the links 62, 61, and the load of the bottom 4 and the lifting frame 3, etc. is received by the receiving members 66. This reduces the load on the telescopic rod R of the actuator A1. When the load on the telescopic rod R falls below the reference load, the ratchet mechanism causes the gear mechanism of the actuator A1 to spin freely, prohibiting the actuator A1 from moving downward, and the bottom 4 is maintained at the lower limit position.

If downward movement is prohibited (YES in step S3), and step S5 is executed without executing step S4, when the height of the bottom 4 reaches the lower limit of the movable range, the lift frame 3 is raised by the upward movement of actuator A1 (step S5), and the bottom 4 cannot be maintained at the lower limit position.

However, even if downward movement is prohibited (YES in step S3), if the bottom 4 is not above the lower limit position (NO in step S4), the electric bed 1 will not raise the lifting frame 3, making it possible to maintain the bottom 4 at the lower limit position.

The linkage mechanism between the telescopic rod R of the actuator A1 and the lifting frame 3 via the bracket 65 and the X-shaped link mechanism 6 has some play. Therefore, the bottom 4 reaches the lowest position before the telescopic rod R is fully retracted.

The flowchart in FIG. 7 has been explained using an example of a downward movement in which the height of the bottom 4 is lowered by actuator A1 when the height lowering button 80D is pressed. However, even in the case of a downward movement in which the head lowering button 81D, back lowering button 82D, and foot lowering button 83D are pressed and the head bottom 41, back bottom 42, knee bottom 44, and leg bottom 45 are changed in position by actuators A2, A3, and A4, the same effect can be obtained by executing the operations in the flowchart shown in FIG. 7.

The electric bed 1 does not necessarily need to execute steps S3 to S5, and does not need to move the bottom 4 upward when the downward movement of the actuator A is prohibited.

1 Electric bed 2 Base unit 3 Lifting frame (receiving member)
4 Bottom 6 X-shaped link mechanism 7 Control unit 8 Hand switch (operation unit)
21, 21 Support frame 22 Leg base 23, 24, 25 Support column 27 Connecting rod 31, 31 Guide member 41 Head bottom 42 Back bottom 43 Seat bottom 44 Knee bottom 45 Leg bottom 51 Headboard 52 Footboard 61, 62 Link 63 Axis 64 Connecting rod 65 Bracket 66 Receiving member 80D Height lowering button 80U Height raising button 81D Head lowering button 81U Head raising button 82D Back lowering button 82U Back raising button 83D Foot lowering button 83U Foot raising button 86 Power switch 87 Display unit 211 Guide members 411, 421, 441, 451 Movable frame 412 Hinge (receiving member)
442 hinge 422, 443 link mechanism A, A1, A2, A3, A4 actuator AC, A1C, A2C, A3C, A4C control module C control box M drive unit R telescopic rod

Claims (2)

Bottom and
An actuator for changing the attitude or height of the bottom;
a receiving member that receives a downward load of the bottom at a lower limit position in a movable range of the bottom;
an operation unit that receives operation instructions from a user;
a control unit that controls an operation of the actuator in response to an operation instruction received by the operation unit;
a prohibition mechanism that prohibits a downward movement of the actuator that changes the attitude or height of the bottom downward when a load applied to the actuator is less than a predetermined reference load,
The actuator comprises:
A motor;
A telescopic rod connected to the bottom;
a gear mechanism that extends and retracts the telescopic rod by a rotational driving force of the motor,
When the telescopic rod is contracted, the downward movement occurs.
When the telescopic rod is extended, the bottom moves upward to change its position or to raise it.
In an electric bed , the prohibiting mechanism is a ratchet mechanism that prohibits the downward movement by causing the gear mechanism to spin freely when the load in the direction of contracting the telescopic rod is less than the reference load. The control unit is
during a descending period in which an operation instruction for the downward movement is accepted by the operation unit, when the downward movement of the actuator is prohibited and the bottom is located above the lower limit position, executing an upward movement by the actuator to change the position or raise the bottom upward;
The electric bed according to claim 1 , wherein, during the lowering period, when the downward movement of the actuator is prohibited and the bottom is located at the lower limit position, the actuator is not caused to perform the upward movement.

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