JP4618063B2 - Wheelchair step device - Google Patents

Description

  The present invention relates to a step device for a wheelchair seated person to place his / her foot on. The step device according to the present invention can be particularly preferably applied to a wheelchair that can also be used as a seat in a vehicle interior.

As a technique related to a step device on which a person sitting in a wheelchair puts his / her foot, there is a technique disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-260087. This document describes an electric step device configured to move a step plate up and down to an arbitrary height by a set of lifting mechanisms having an electric motor and a screw shaft mechanism.
JP 2005-13497 Japanese Patent Laid-Open No. 2003-260087

However, according to the conventional electric step device, in addition to the lifting mechanism having the screw shaft rotated by the electric motor and the nut meshed with the screw shaft, the lifting base to which the step plate is attached is guided so as to be movable up and down. For this reason, a guide mechanism mainly composed of a guide shaft is provided. For this reason, the conventional step apparatus has a problem in that the configuration is complicated and the size is increased, and as a result, a large installation space is required at the feet of the seated person, and the cost is increased.
The present invention has been made in view of the above-described conventional problems, and since the structure is compact while having sufficient rigidity against a load applied by a seated person placing his / her foot on a step plate, the present invention has been made. It is an object of the present invention to provide a step device that does not require such a large installation space and can be reduced in cost.

For this reason, this invention set it as the step apparatus of the structure described in each claim of a claim.
According to the step device of the first aspect, the elevating base provided with the step plate is connected to the nut whose upper part moves up and down by the rotation of the screw shaft, and the back side is supported by the receiving roller below the nut. Therefore, the load applied by the seated person placing his / her foot on the step plate is firmly received by the nut and the receiving roller, and the lifting base and the step plate can be smoothly moved up and down by the movement of the nut. . In this way, the step plate can be moved up and down smoothly while receiving a load applied to the step plate without using a conventional guide mechanism having a guide shaft, so the configuration is more compact than before. Therefore, it can be installed in a smaller space, and its cost can be reduced.
Further , according to the step device of the first aspect, even if the lifting base is not accurately assembled in parallel to the screw shaft due to a processing error or an assembly error of the member, the lifting base is attached to the nut. On the other hand, since this error is absorbed by displacing back and forth, it is possible to eliminate the lifting and twisting of the receiving roller with respect to the lifting base and maintain a good receiving state of the lifting base by the receiving roller. The base can be smoothly lifted and secured with respect to the load.

Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an entire wheelchair 1 including a step device 50 according to the present embodiment. The wheelchair 1 is connected to a seat moving device 100 installed in the room of the vehicle M, and can be moved between the inside and outside of the vehicle interior by the operation of the seat moving device 100, and can be used as a vehicle seat in the vehicle interior. Outside the room, it can be used alone as a wheelchair capable of self-propelled by being separated from the seat moving device 100. FIG. 7 shows a state in which the wheelchair 1 of this example is moved to the driver seat of the vehicle M and functions as a driver seat.
First, the wheelchair 1 will be described. The wheelchair 1 includes a seat cushion 2 and a seat back 3. A headrest 4 is provided at the upper end of the seat back 3. In addition, armrests 5 and 5 are provided on the left and right sides of the seat back 3. A joystick type operation panel 6 is arranged at the front end of the armrest 5 on the right side when viewed from the seated person so that the seated person can run the wheelchair 1.
Front wheels 8 and 8 are supported on the front left and right sides of the seat frame 7 that supports the seat cushion 2, and rear wheels 9 and 9 are supported on the rear left and right. The front and rear wheels 8 and 9 are rotated upward by an electric storage mechanism (not shown) using an electric motor as a drive source, and are stored at positions along the side portions of the seat cushion 2. In FIG. 5, the front and rear wheels 8 and 9 taken out downward are indicated by solid lines, and the front and rear wheels 8 and 9 stored upward are indicated by dotted lines.
Further, the left and right rear wheels 9, 9 incorporate a wheel motor (not shown) that is driven by a battery 10 (supply voltage 24V) mounted on the back of the seat back 3 as a power source. The left and right rear wheels 9, 9 are actively rotated by a built-in wheel motor. The wheelchair 1 moves forward when the left and right rear wheels 9, 9 rotate forward, and moves backward when reversed. Switching between forward and reverse, that is, switching of the rotation direction of the wheel motor is performed by operating the operation panel 6 described above.

The wheelchair 1 of the present embodiment is characterized by a step device 50 provided on the front surface of the seat frame 7. Details of this step device 50 are shown in FIGS. The step device 50 includes a pair of left and right step plates 51, 51 and a pair of left and right lifting mechanisms 52, 52 arranged on the left and right corresponding to the step plates 51, 51, respectively. The seated person can place the left and right feet on the step plates 51, 51. The right step plate 51 is moved up and down by the right lifting mechanism 52, and the left step plate 51 is moved up and down by the left lifting mechanism 52. Since the left and right elevating mechanisms 52 and 52 have the same configuration, only one configuration will be described below.
The lifting mechanism 52 includes a fixed base 53 fixed to the front surface of the seat frame 7. The fixed base 53 is fixed in a state where the lower side thereof is slightly inclined in a direction in which it is displaced forward (left side in FIG. 3). An electric motor 54 and its speed reducer 54 a are attached to the upper portion of the fixed base 53.
The electric motor 54 is driven by using the battery 10 mounted on the back surface of the seat back 3 as a power source. The operation panel 6 is provided with a lift switch (not shown) of the step device 50. By operating this elevating switch, the electric motor 54 is activated and the rotation direction is switched, whereby the left and right elevating devices 52, 52 are operated, and the left and right step plates 51, 51 are moved up and down. Description of the drive circuit including the electric motor 54, the battery 10, and the lift switch is omitted.
The output of the electric motor 54 is decelerated by the speed reducer 54a. A screw shaft 55 is coaxially connected to the output shaft of the speed reducer 54a. The screw shaft 55 is supported by the fixed base 53 such that the upper and lower portions of the screw shaft 55 are rotatable around the shaft via a bearing (not shown). As shown in the figure, the screw shaft 55 is supported substantially parallel to the fixed base 53. For this reason, the screw shaft 55 is also provided in a slightly inclined state in such a direction that its lower side is displaced forward. When the electric motor 54 is activated, the screw shaft 55 rotates around the axis. In the present embodiment, a so-called trapezoidal screw having a screw thread having a trapezoidal cross section is used for the screw shaft 55.

A nut 56 is engaged with the screw shaft 55. When the screw shaft 55 is rotated about its axis by the electric motor 54, the nut 56 moves up and down along the screw shaft 55. The vertical movement direction of the nut 56 is slightly inclined with respect to the vertical direction. That is, the nut 56 moves up and down along a direction inclined so as to be displaced forward as it is displaced downward.
The upper part of the elevating base 57 is connected to the nut 56. FIG. 4 shows details of the support structure for the upper portion of the elevating base 57 with respect to the nut 56. As shown in FIG. 4, a flat rubber plate 58 is sandwiched between the upper portion of the elevating base 57 and the nut 56. The upper portion of the elevating base 57 is fixed to the nut 56 with fixing bolts 59 with the rubber plate 58 sandwiched therebetween. The fixing bolt 59 is fastened to the nut 56 via a washer 59a and a collar 59b.
As described above, the elevating base 57 is attached to the nut 56 with the rubber plate 58 interposed therebetween, so that the elevating base 57 has a floating structure that can be displaced in a predetermined range with respect to the nut 56 in the front-rear direction. It is connected to. The rubber plate 58 in the present embodiment corresponds to an example of an elastic member described in the claims. According to this floating structure, even when the wheel 7 is traveling, for example, even when the front wheel 8 rides on a step on the road and the frame 7 undergoes a slight deformation (deflection), this deformation is not affected by the rubber plate 58. Therefore, the displacement of the elevating base 57 and the step plate 51 due to the deformation can be suppressed, and thus the position (height) of the seated person's foot can be held at a constant position. Can improve the sitting comfort.
The elevating base 57 is received from the back side by a single receiving roller 60 provided below the fixed base 53 below the moving range of the nut 56. By receiving the back side by the receiving roller 60, the lifting base 57 is supported substantially in parallel with the screw shaft 55 and the fixed base 53. Further, the elevating base 57 moves up and down while maintaining the state in which the nut 56 is moved in parallel, that is, the screw shaft 55 and the fixed base 53 are always parallel.

As described above, the elevating base 57 is supported in a state of being inclined in a direction in which the lower side is displaced forward, and is mainly received from the lower side by the receiving roller 60 in a state where the lower side is placed on the receiving roller 60. Move up and down For this reason, for example, there is no need to use an expensive linear motion guide mechanism (for example, trade name LM guide) or the like, and an upper portion added to the elevating bases 57 and 57 without using a separate slide bar as in the prior art. Smooth elevating operation is ensured while ensuring the supporting rigidity of the elevating bases 57 and 57 with respect to the load (load applied by placing a foot on the step plate 51 by the seated person). .
A step plate 51 is supported on the lower part on the front side of the elevating base 57. A support bar 63 is supported on the lower part of the front side of the elevating base 57 via a support shaft 62 so as to be rotatable up and down. As shown by the solid line in FIG. 3, the support bar 63 rotates downward and protrudes forward at a position substantially orthogonal to the lifting base 57. On the other hand, as shown by a two-dot chain line in FIG. 3, when the support bar 63 is rotated upward, the support bar 63 is substantially along the lift base 57.
A step plate 51 is supported on the support bar 63 so as to be rotatable up and down. The step plate 51 is taken out to a use position that pivots downward and projects substantially horizontally. As shown in FIGS. 1 and 2, the left and right step plates 51, 51 are rotated to the side (inner side) approaching each other and taken out. If the left and right support bars 63, 63 are horizontally taken out and the step plate 51 is turned upward to stand, the feet of the seated person are opened. This state is not shown in the figure. Further, when the support bars 63, 63 are rotated upward with the left and right step plates 51, 51 being taken out horizontally as indicated by a two-dot chain line in FIG. Stored along. In this state, the seated person can use his / her feet more widely.

The front of the step device 50 excluding the left and right step plates 51, 51 is covered with a cover 65. The cover 65 prevents the seated person's feet from coming into contact with the electric motor 54 or the lifting base 57 or the like.
Further, as shown in FIG. 2, the left and right lifting bases 57, 57 are connected by a connecting bar 66. For this reason, the left and right lifting bases 57 and 57 are lifted and lowered integrally through the connecting bar 66, and therefore the left and right step plates 51 and 51 are lifted and lowered integrally.
As shown by a two-dot chain line in FIG. 3, the left and right step plates 51, 51 are lowered from the road surface L to a use height (use position) of about 50 mm. When the wheelchair 1 is self-propelled on the road surface L, both the step plates 51 and 51 are lowered to the use position so that the seated person puts both feet on the step plates 51 and 51 in an easy posture. I can leave.
On the other hand, when the electric motors 54 and 54 are reversed, both the step plates 51 and 51 rise. In the case of this embodiment, both the step plates 51 and 51 can be moved up to the storage position (storage height) by raising about 110 mm from the above-mentioned use position (use height). Both steps with respect to the rocker portion R that defines the lower portion of the door opening K when the wheelchair 1 is moved between the vehicle interior and the exterior by the seat moving device 100 described later by raising both the step plates 51, 51 to the storage position. Interference between the plates 51 and 51 can be avoided with a smaller lift amount.
The storage positions of the step plates 51 and 51 are detected by the sensor 64. The sensor 64 is attached to the upper part of the fixed base 53. When the elevating base 57 rises and the step plate 51 reaches the retracted position, the dog 67 attached to the nut 56 comes close to the sensor 64, whereby the sensor 64 is turned on and the left and right step plates 51, 51 reach the retracted position. Is detected.

Next, the wheelchair 1 provided with the above step device 50 can be moved between the vehicle interior and the exterior by the seat moving device 100 provided in the vehicle M. The sheet moving apparatus 100 has the same configuration as that disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-34325, and no particular change is required in the present embodiment, but will be briefly described below.
As shown in FIG. 6, a front / rear slide mechanism 110 is provided on the vehicle floor F at the driver's seat position of the vehicle M. The front / rear slide mechanism 110 has a configuration in which the front / rear slide base 112 is slid in a certain range along the vehicle front-rear direction (direction orthogonal to the paper surface in FIG. 6) using the electric motor 111 as a drive source.
The front and rear slide base 112 is provided with a turntable 120. The turntable 120 includes an outer ring 121 and an inner ring 122 that are assembled so as to be rotatable relative to each other. The outer ring 121 is fixed to the front / rear slide base 112. The inner ring 122 is positively rotated by a rotary motor 123 attached on the front / rear slide base 112. The inner ring 122 is fixed to the lower surface of the rotation base 130. When the rotation motor 123 is activated, the rotation base 130 is rotated, whereby the wheelchair 1 is rotated about 90 ° between a position facing the front of the vehicle and a position facing the door opening K side.

A lateral slide mechanism 102 is configured on the rotation base 130. The lateral slide mechanism 102 operates when the wheelchair 1 is moved mainly in the vehicle width direction (left-right direction in FIG. 6). A pair of left and right horizontal slide rails 131, 131 are mounted on the rotating base 130. A horizontal slide base 132 is slidably supported along the horizontal slide rails 131 and 131. The horizontal slide base 132 is slid by a slide motor and a screw shaft mechanism (not shown).
One end side of link arms 133a and 133b constituting the four-bar linkage mechanism 133 is connected to the left and right side portions of the horizontal slide base 132 so as to be rotatable up and down. An auxiliary slide mechanism 135 is provided between the distal ends of the pair of left and right four-bar linkage mechanisms 133 and 133. The auxiliary slide mechanism 135 is provided with a connection base 101 that can slide in the horizontal direction. As will be described later, the wheelchair 1 is connected to the seat moving device 100 via the connection base 101.
When the horizontal slide base 132 slides in the vehicle width direction, the left and right four-bar linkage mechanisms 133 and 133 tilt in the vertical direction while moving in the vehicle width direction, whereby the auxiliary slide mechanism 135 provided between the front ends thereof is The wheelchair 1 connected to the connection base 101 of the auxiliary slide mechanism 135 is moved up and down while moving between the outsides, and is moved between the outside and the inside of the vehicle while moving up and down between the height near the road surface L outside the vehicle and the floor F inside the vehicle Can be made. When the connection base 101 of the auxiliary slide mechanism 135 slides in the horizontal direction, the wheelchair 1 connected thereto horizontally moves between the descent start position on the door opening K side and the driver seat position on the vehicle interior side. Is done.

As shown in FIG. 5, the wheelchair 1 is moved backward to approach the connection base 101 while the connection base 101 is lowered to a height close to the road surface L outside the passenger compartment. The wheelchair 1 is further retracted as it is, and the connection base 101 enters the lower surface side of the seat cushion 2. In a state where the connection base 101 has entered the lower surface side of the seat cushion 2, the lateral slide mechanism 102 is lifted by the connection base 101 by the horizontal slide base 132 retracting toward the vehicle interior side and starting up to the ascending side. It is done. When the wheelchair 1 is raised and the front and rear wheels 8 and 9 are lifted from the road surface L, the front and rear wheels 8 and 9 are stored upward by an electric storage mechanism (not shown).
Further, as the front and rear wheels 8 and 9 are retracted, the electric motors 54 and 54 are activated and the left and right step plates 51 and 51 are raised to the retracted position. The storing operation of the front and rear wheels 8 and 9 and the storing operation of both the step plates 51 and 51 are automatically performed in conjunction with the operation of the sheet moving device 100. The storage positions of the front and rear wheels 8 and 9 and the storage positions of both step plates 51 and 51 are detected by sensors, respectively. The storage positions of both step plates 51, 51 are detected by the sensors 64, 64.
When the retracted positions of the front and rear wheels 8 and 9 and the retracted positions of the left and right step plates 51 and 51 are respectively detected by the sensors, the seat moving device 100 continues to operate toward the interior of the vehicle, thereby raising the wheelchair 1 and opening the door. The opening K is returned to the lowering start height. Thereafter, the connection base 101 of the auxiliary slide mechanism 135 slides toward the vehicle interior side, and the wheelchair 1 moves toward the vehicle interior side. The wheelchair 1 moved to the vehicle interior side is rotated to a position facing the front of the vehicle by the operation of the turntable 120 and the front / rear slide mechanism 110.

With the above operation, the seated person can move (ride) to the driver's seat position in the passenger compartment while sitting on the wheelchair 1 outside the passenger compartment. This state is shown in FIG. In FIG. 7, symbol H indicates a steering handle, and symbol B indicates a brake pedal. After the wheelchair 1 is moved to the driver's seat position, the elevating mechanism 52, 52 of the step device 50 is operated to the lowering side, and the left and right step plates 51, 51 are lowered to the use position, so that the seated person can easily The steering handle H can be gripped in the posture.
By operating the seat moving device 100 in reverse, the seated person can move (get off) outside the passenger compartment while sitting on the wheelchair 1 at the driver seat position in the passenger compartment. In this case, first, the electric motors 54, 54 of the step device 50 are reversed to return the left and right step plates 51, 51 to the storage position. Thereafter, the front / rear slide mechanism 110 and the turntable 120 of the seat moving device 100 are operated, and the wheelchair 1 is rotated about 90 ° from the position facing the front of the vehicle and directed toward the door opening K side. Next, the connection base 101 of the auxiliary slide mechanism 135 slides outside the vehicle compartment, and the wheelchair 1 in a state directed toward the door opening K side moves horizontally through the door opening K to the vehicle compartment outside. By the operation of the rear lateral slide mechanism 102, the wheelchair 1 moves to the outside of the passenger compartment while descending. In the middle of the wheelchair 1 moving down to the outside of the passenger compartment, the front / rear wheel retracting mechanism is operated and the front and rear wheels 8 and 9 are taken out downward, and the elevating mechanism 52 is operated and the left and right step plates 51 are operated. , 51 are lowered to the use position. Thereafter, the front and rear wheels 8 and 9 are brought into contact with the road surface L. After the wheelchair 1 is lowered onto the road surface L in this way, the seat moving device 100 is further moved downward so that the connecting base 101 is separated from the wheelchair 1 and then the wheelchair 1 is advanced. Thus, the wheelchair 1 is separated from the seat moving device 100. The separated wheelchair 1 can independently travel on the road surface L.
Thus, when the wheelchair 1 connected to the seat moving device 100 passes through the door opening K of the vehicle M, the left and right step plates 51 and 51 are stored in the upper storage position and are moved downward from the seat cushion 2. Since the overhang dimension of the door is small, it is easy to avoid the interference of the rocker portion R that defines the lower portion of the door opening K. As a result, the height of the wheelchair 1 when passing through the door opening K is correspondingly increased. Can be lowered. According to this, the slide amount or the like of the lateral slide mechanism 102 can be reduced, and as a result, the sheet moving apparatus 100 can be configured in a compact manner.

According to the step device 50 of the present embodiment configured as described above, the left and right step plates 51 and 51 are moved up and down by the lifting mechanism 52 using the electric motor 54 as a drive source. In the left and right elevating mechanisms 52, 52, the elevating base 57 provided with the step plate 51 is connected to the nut 56 at the upper part and is received from the back side by the receiving roller 60. Therefore, the load applied by the seated person placing his / her foot on the step plate 51 is firmly received by the nut 56 and the receiving roller 60, and the lifting / lowering base 57 and the step plate 51 are smoothly lifted / lowered by the movement of the nut 56. Can be moved. Therefore, the step plate 51 can be moved up and down smoothly while receiving a load applied to the step plate 51 without using a conventional guide mechanism having a guide shaft. It can be made compact, so that it can be installed in a smaller space, and its cost can be reduced.
Further, since the upper part of the lifting base 57 is supported by the nut 56 with the rubber plate 58 sandwiched therebetween, and the lower part is provided with a floating structure on which the receiving roller 60 is placed, Even when the front wheel 8 rides on a step on the road surface L and the frame 7 is slightly deformed (bent), the nut 56 is slightly displaced (inclined). 58, the displacement due to the deformation of the lifting base 57 and the step plate 51 can be suppressed, and the position (height) of the seated person's foot can be held at a fixed position. It can improve the comfort of wheelchair.
Further, since the left and right step plates 51 and 51 are moved up and down by the lifting mechanisms 52 and 52 using the electric motor 54 as a drive source, when the embodiment in which the wheelchair 1 is moved between the vehicle interior and the exterior by the seat moving device 100 is adopted. The operation of the seat moving device 100 can be controlled in association with the ascending / descending operation of the step device 50, and a user-friendly wheelchair can be provided in this respect.
Further, in the illustrated step device 50, a lifting base 57 that supports the step plate 51 is attached to a nut 56 that is moved by the rotation of a screw shaft (trapezoidal screw) 55, and is moved up and down by the vertical movement of the nut 56. Therefore, for example, the elevating base 57 can be raised and lowered without using an expensive linear motion mechanism called a trade name LM guide, and the cost of the wheelchair 1 can be reduced also in this respect.

Various modifications can be made to the embodiment described above. For example, although the wheelchair 1 in a form that can be used as a vehicle seat by moving the interior and exterior of the vehicle by the seat moving device 100 is illustrated, the invention can be similarly applied to a wheelchair that is used independently of the vehicle.
The left and right elevating bases 57 and 57 are illustrated as being received by a single receiving roller 60, but the elevating base is provided at two locations on the back side by two receiving rollers arranged at a certain interval in the width direction. It is good also as a structure received by.
Further, the configuration in which the upper portion of the lifting base 57 is floatingly supported by the nut 56 with the rubber plate 58 sandwiched therebetween is illustrated, but the rubber plate 58 (floating support structure) is omitted and the upper portion of the lifting base 57 is fixed to the nut. Thus, it is possible to adopt a configuration in which the lower side is received by the receiving roller while being fixed directly so that it cannot be displaced. Even in this configuration (non-floating structure), the receiving roller 60 does not float with respect to the lifting base 57, and an excessive force is not applied to the receiving roller 60 (squeezing). It is possible to maintain a good contact state of the receiving roller 60 with respect to.
Further, the rubber plate 58 is exemplified as an elastic member for floatingly supporting the lifting base with respect to the nut. However, instead of the rubber plate 58, for example, a compression spring is interposed between the upper portion of the lifting base and the nut. It is good.
Further, although the configuration in which the receiving roller 60 is provided on the fixed base 53 is illustrated, a load applied to the lifting base is generated by providing the receiving roller on the lifting base 57 side and rolling the receiving roller with respect to the fixed base. It is good also as a structure which supports the said raising / lowering base so that raising / lowering is possible, receiving with this receiving roller.

It is the whole wheelchair provided with the step device concerning the embodiment of the present invention. It is a front part of a wheelchair, Comprising: It is a perspective view of a step apparatus. It is a front part of a wheelchair, Comprising: It is a side view of a step apparatus. FIG. 4 is an enlarged view of part (4) of FIG. 3, and is a longitudinal sectional view showing a support structure for the upper part of the lifting base with respect to the nut. It is a side view which shows a mode just before a wheelchair is connected with a seat moving apparatus. It is a side view which shows a mode that a wheelchair is connected with a seat moving apparatus and moves to a vehicle interior. In FIG. 6, it is the figure which looked at the wheelchair from the arrow (6) direction, Comprising: It is the side view of the wheelchair which moved to the driver's seat position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheelchair 2 ... Seat cushion 3 ... Seat back 6 ... Control panel 7 ... Seat frame 8 ... Front wheel 9 ... Rear wheel 10 ... Battery 50 ... Step device 51 ... Step board 52 ... Lifting mechanism 53 ... Fixed base 54 ... Electric motor 55 ... Screw shaft 56 ... Nut 57 ... Elevating base 58 ... Rubber plate (elastic member)
60: Receiving roller 64: Sensor (for storing position detection)
65 ... cover 66 ... connecting bar 100 ... sheet moving device 101 ... connecting base 102 ... side slide mechanism 110 ... front / rear slide mechanism 120 ... rotating disc 130 ... rotating base 133 ... four-bar linkage mechanism M ... vehicle K ... door opening F ... Vehicle floor R ... Locker L ... Road surface

Claims (1)

A step device for a wheelchair equipped on the front surface of a seat frame of a wheelchair, comprising a step plate on which a seated person puts his / her foot, and an elevating mechanism for raising and lowering the step plate,
The elevating mechanism is an electric motor attached to an upper portion of a fixed base that is disposed and fixed in the vertical direction of the elevating direction on the front surface of the seat frame of the wheelchair ,
A screw shaft that is arranged in the vertical direction in the ascending / descending direction in parallel with the fixed base, is supported by the fixed base in a state in which an upper part and a lower part are rotatable about an axis, and is rotated about the axis by the electric motor;
A nut that meshes with the screw shaft and moves up and down along the screw shaft by rotation of the screw shaft;
An elevating base disposed in parallel with the screw shaft and the fixed base in an up-and-down direction, and having an upper portion coupled to the nut and movable integrally with the nut in the up-and-down direction of the elevating direction ;
A receiving roller provided at a lower part of the fixed base at a position lower than a moving range of the nut and receiving a back side of the elevating base;
The step plate is provided at the lower front side of the lifting base,
Between the lifting base and the nut, floating structure can be displaced in the longitudinal direction of the lift base with an elastic member is interposed the nut for absorbing the displacement of the nut and be Rutotomoni,
A wheelchair in which the lifting base of the lifting mechanism is also tilted in the same direction by fixing the lifting base of the lifting mechanism to the seat frame so that the lower side thereof is displaced forward. step device.

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