JP2008049029A - Step device of wheelchair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a step device allowing a seated person in a wheelchair equipped with the electric lift type step device to comfortably operate the device to descend without such a trouble that the seated person may feel uneasy when the external force in the direction of rearward inclination is applied to the wheelchair by the reactive force from the road surface generated if the descending motion of a step board is restrained when the step board runs on an obstacle such as difference in level on the road surface on the way of descending. <P>SOLUTION: If the external force of at least a certain level is applied to a screw shaft 55 when the step board runs on the obstacle such as the difference in level on the road surface on the way of descending, a driving side member 81 and a driven side member 82 of a joint 80 for connecting the screw shaft to an electric motor 54 are slid to each other in the direction of rotation to block the motor power. <P>COPYRIGHT: (C)2008,JPO&INPIT

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 compartment.

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. 2003-199796. The step device disclosed in this document is an electric step device that raises and lowers a step plate using a set of screw shaft mechanisms using an electric motor as a drive source, and a seated person operates a step elevating switch. It is equipped with a position adjustment function that makes it possible to adjust the position of the step plate to an arbitrary height position, and a sensor for detecting the rising and falling end positions of the step plate, and the step plate is at the rising end position or the falling end position. When it reaches, it has an automatic stop function that automatically stops the electric motor by the operation of the sensor.
JP 2003-199796

However, according to the above-described conventional electric step device, the step plate continues to rise or fall while the occupant operates the step lift switch between the rising end position and the lower end position of the step plate. Therefore, for example, when the step board descends on the stepped part of the road surface or the floor of the building when the step board descends, if the seated person continues to operate the step up / down switch to the down side, the step board The reaction force generated by being pressed against the step portion acts in the direction of tilting the wheelchair backward, and as a result, the seated person becomes unstable and feels uneasy.
In addition, for example, when this type of electric step device is installed in a wheelchair (vehicle seat) that is used as a seat in a vehicle interior and is used alone as a wheelchair outside the vehicle interior, the front and rear of the wheelchair in the vehicle interior When the step plate is lowered while the wheel is folded upward, it comes into contact with the vehicle floor before reaching the lower end, and in this case, the same problem as described above occurs.
Therefore, according to the present invention, when the resistance to the lowering operation is added to the step plate just before the step plate reaches the lowering end, the seated person or the like remains operating the step up / down switch to the lower side. It is another object of the present invention to provide a step device that can prevent a reaction force in a tilting direction from acting on a wheelchair, and that allows a seated person to operate with confidence.

For this reason, this invention set it as the step apparatus of the structure described in each claim of a claim.
According to the first aspect of the present invention, when the step plate interferes with an obstacle during the lowering operation of the step plate and the lowering operation is restricted, a rotational resistance is added to the screw shaft. The drive side member is separated in the rotation direction with respect to the driven side member on the shaft side, and the power of the electric motor is cut off. As described above, when the lowering operation of the step plate is restricted by the obstacle, the power of the electric motor is cut off and the power in the lowering direction is not transmitted to the step plate. Since the reaction force in the backward tilt direction does not act, and therefore the seated person does not feel uneasy, the step device can be operated in a downward direction with peace of mind.
Obstacles in which the step board during the lowering operation is restricted from the lowering operation include various other articles such as a vehicle floor, a step on the road surface, and a step (stairs) on the floor of the building.

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 first 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. 11 shows a state in which the wheelchair 1 of this example is moved to the driver seat position of the vehicle M and used 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. 9, 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 two-dot chain 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 positively rotated by a built-in wheel motor, whereby the wheelchair 1 can be self-propelled. 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 first 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. Details of one lifting mechanism 52 are shown in FIG.
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 an output speed reduction gear head 54 a are attached to the upper portion of the fixed base 53 via a motor bracket 70. In FIG. 2, the motor bracket 70 is not shown.
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 step lift switch (not shown) of the step device 50. By operating the step elevating switch, the electric motor 54 is activated and the rotation direction is switched, whereby the left and right elevating devices 52 and 52 are operated to move the left and right step plates 51 and 51 up and down. Description of the drive circuit including the electric motor 54, the battery 10, and the step up / down switch is omitted.

The output shaft 54b of the electric motor 54 (the output shaft of the gear head 54a) is formed as a rectangular axis having a rectangular cross section. A screw shaft 55 is coaxially connected to the output shaft 54 b via a joint 80. The joint 80 has a power cutoff function that does not transmit the rotational power of the electric motor 54 to the screw shaft 55 side under a certain condition during the step-down operation. Details of this joint 80 are shown in FIG.
The joint 80 is divided into a drive side member 81 on the electric motor 54 side and a driven side member 82 on the screw shaft 55 side in the power transmission direction. The drive side member 81 has a substantially cylindrical shape, and a rectangular connection hole 81a is formed on the upper surface thereof. The output shaft 54b of the electric motor 54 is inserted into the connecting hole 81a so as to be relatively displaceable in the axial direction and not to be relatively rotatable. The connecting hole 81a is a bottomed hole having a certain depth, and a compression spring 83 is interposed between the bottom of the connecting hole 81a and the tip end surface of the output shaft 54b. By this compression spring 83, the drive side member 81 is urged axially downward (the driven side member 82 side) with respect to the output shaft 54b. A support shaft portion 81 b is integrally provided at the center of the lower surface of the drive side member 81. Around the support shaft portion 81b, a plurality of engagement protrusions 81c to 81c are formed at equal intervals along the circumferential direction. Each engagement protrusion 81c includes an engagement surface 81ca orthogonal to the rotation direction and an inclined surface 81cb.
On the other hand, the driven member 82 has a substantially cylindrical shape, and a support hole 82a into which the support shaft portion 81b is rotatably inserted without rattling is formed on the upper surface thereof. Around the support hole 82a, a plurality of receiving projections 82c to 82c are formed at equal intervals along the circumferential direction, and the engagement projections 81c to 81c of the drive side member 81 are engaged in the circumferential direction. Yes. Each receiving protrusion 82c includes a receiving surface 82ca that is orthogonal to the rotational direction and an inclined surface 82cb that is inclined. The engaging protrusions 81c of the driving member 81 are engaged with the receiving protrusions 82c on the driven member 82 side in the rotation direction, so that both the members 81 and 82 are integrated with respect to the rotation. The rotation output of the electric motor 54 is transmitted to the screw shaft 55 side.
Further, a connecting hole 82b is provided on the lower surface of the driven member 82 coaxially with the support hole 82a. This connection hole 82b is subjected to so-called serration processing. The drive shaft portion 55c of the screw shaft 55 is inserted into the connection hole 82b. This drive shaft 55c is also serrated. Therefore, the drive shaft portion 55c is meshed with the connecting hole 82b in the rotational direction and connected integrally. However, the driven member 82 is connected to the drive shaft 55c so as not to be displaced in the axial direction by a retaining ring (not shown).

As shown in FIG. 6, at the stage where the electric motor 54 rotates to the step-up side, the engagement surface 81 ca of each engagement projection 81 c of the drive side member 81 and the reception surface of each reception projection 82 c of the driven side member 82. 82ca always contacts and meshes with each other, whereby both members 81 and 82 are integrally rotated to the step-up side.
In addition, as shown in FIG. 7, the electric motor 54 is rotated to the step downward side, and the left and right step plates 51 and 51 are lowered without receiving any resistance. Is not added, the inclined surface 81 cb of each engaging protrusion 81 c of the driving side member 81 and the inclined surface 82 cb of each receiving protrusion 82 c of the driven side member 82 are pressed in the axial direction by the urging force of the compression spring 83. Due to the engagement (friction) of the two inclined surfaces 81cb and 82cb, the two members 81 and 82 are integrally rotated in the step lowering direction, so that the screw shaft 55 is rotated in the step lowering direction and the left and right step plates 51 and 51 are moved. Descend.
On the other hand, as shown in FIG. 8, the electric motor 54 is rotated to the step downward side, and the lowering operation is regulated by the step plates 51, 51 riding on the road surface step D or the like during the downward movement. As a result, when a large rotational resistance is applied to the screw shaft 55, the drive side member 81 is compressed by the sliding contact between the inclined surface 81cb of the engaging protrusion 81c and the inclined surface 82cb of the receiving protrusion 82c. The two members 81 and 82 are rotated relative to each other while being displaced upward against 83, so that the rotational power of the electric motor 54 is cut off and the rotation of the screw shaft 55 is stopped. Thereafter, the electric motor 54 idles.
Support shaft portions 55 a and 55 b are coaxially provided at both ends of the screw shaft 55. The upper support shaft portion 55 a is rotatably supported by the motor bracket 70 via a bearing 71. A lower support shaft portion 55 b of the screw shaft 55 is rotatably supported by the screw shaft bracket 73 via a bearing 72. The screw shaft bracket 73 is fixed to the lower portion of the fixed base 53. Thus, the screw shaft 55 is supported by the fixed base 53 so as to be rotatable between the motor bracket 70 and the screw shaft bracket 73 around the axis. As shown in the figure, the screw shaft 55 is supported in 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.
The drive shaft portion 55c is coaxially and integrally provided on the distal end side of the support shaft portion 55a on the upper side of the screw shaft 55.

Next, as shown in FIGS. 3 and 4, 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.
A lift base 57 is attached to the nut 56. An upper portion 57 a of the elevating base 57 extends upward from the nut 56. As shown in the drawing, the upper end 57a of the elevating base 57 is abutted against the lower surface of the motor bracket 70, whereby the rising end of the elevating base 57 is restricted. Therefore, the motor bracket 70 has a function as a stopper that regulates the lift base 57 and thus the rising ends of the step plates 51 and 51. Therefore, the rising end position of the nut 56 is regulated by the upper portion 57a of the lifting base 57 abutting against the lower surface of the motor bracket 70. On the other hand, the lower end of the nut 56 is regulated by contacting the screw shaft bracket 73.
The lower part of the elevating base 57 is received from the back side by one 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 a state in which the nut 56 is always parallel to the moving direction of the nut 56, that is, the screw base 55 and the fixed base 53.
The elevating base 57 is supported in a state of being inclined in a direction in which the lower side is displaced forward, and the lower side is mainly placed on the receiving roller 60 and received from below by the receiving roller 60. Move up and down. According to this, the support rigidity of the elevating bases 57 and 57 with respect to the load from the upper side applied to the elevating bases 57 and 57 (the load applied when the seated person puts his / her foot on the step plate 51). The smooth raising / lowering operation is ensured while ensuring.

A step plate 51 is supported on the lower part of the front side (left side in FIG. 3) of the lifting 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 clothes from contacting 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.
Both step plates 51 and 51 are moved up and down between a rising end position indicated by a solid line and a falling end position indicated by a two-dot chain line in FIG. When the elevating base 57 rises and the upper end of the elevating base 57 hits the lower surface of the motor bracket 70, the left and right step plates 51, 51 reach the raised end position. 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 ascending end position, both the lock plates R defining the lower portion of the door opening K are separated from each other. Interference between the step plates 51 and 51 can be avoided with a smaller lift amount.
On the other hand, when the nuts 56 and 56 are lowered and come into contact with the screw shaft base 73, the left and right step plates 51 and 51 reach the lowered end position. When the wheelchair 1 is self-propelled on the road surface L, both the step plates 51 and 51 are lowered to the lower end position, so that the seated person puts both feet on the step plates 51 and 51 in an easy posture. I can keep it.

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. 10, 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. 10) 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 has a function of moving the wheelchair 1 mainly in the vehicle width direction (left-right direction in FIG. 10). 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 inside and outside of the vehicle interior while moving up and down between the height near the road surface L outside the vehicle interior and the floor F inside the vehicle interior. 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. 9, in a state where the connection base 101 is lowered to a height close to the road surface L outside the passenger compartment, the wheelchair 1 is moved backward to approach the connection base 101. 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). The retracting operation of the front and rear wheels 8 and 9 is automatically performed in conjunction with the operation of the seat moving device 100.
In addition to the retracting operation of the front and rear wheels 8 and 9, the seated person operates the step lift switch at hand to raise the electric motors 54 and 54 to raise the left and right step plates 51 and 51 to the raised end position. Let The raising operation of both the step plates 51 and 51 is completed when the upper end of each lifting base 57 is abutted against the lower surface of the motor bracket 70.
After the storing operation of the front and rear wheels 8 and 9 and the raising operation of the left and right step plates 51 and 51 are completed, the seat moving device 100 continues to operate toward the interior of the vehicle interior. Is returned to the descending 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. 11, 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 seated person operates the step lift switch at hand to the lowering side to operate the lifting mechanisms 52, 52 of the step device 50 to the lowering side, and the left and right step plates 51 , 51 are lowered until they contact the vehicle floor F.
At this time, the left and right step plates 51, 51 abut against the vehicle floor F before reaching the lowered end position. When the left and right step plates 51 and 51 come into contact with the vehicle floor F while the occupant operates the step up / down switch to the lower side, the lowering is prevented. Ascending reaction force acts. The reaction force on the rising side with respect to both step plates 51, 51 is added as a rotational resistance with respect to the screw shaft 55.
As described above, when a rotational resistance is applied to the screw shaft 55 during the operation of the electric motors 54, 54 on the step downward side, the drive side member 81 of the joint 80 moves up against the compression spring 83 to follow the driven side. The rotational engagement with the member 82 is disengaged, whereby the power transmission of the electric motor 54 via the joint 80 is cut off, and the rotation of the screw shaft 55 is stopped.
For this reason, immediately after the left and right step plates 51, 51 contact the vehicle floor F, the driving force in the downward direction with respect to both the step plates 51, 51 is cut off. It stops at the position where it abuts. The stop of the step plate 51 at this stage is performed while the seated person has operated the step lift switch to the lower side. Thereafter, when the seated person stops the operation of the step lift switch, the electric motors 54 and 54 are stopped.
As described above, after the wheelchair 1 is moved to the driver seat position in the passenger compartment, the step lift switch is operated to the lower side to lower the left and right step plates 51, 51. Immediately after coming into contact with F, a rotational resistance is applied to the screw shaft 55, whereby the drive side member 81 of the joint 80 rotates relative to the driven side member 82, thereby interrupting the rotational power of the electric motor 54. Therefore, even if the left and right step plates 51, 51 come into contact with the vehicle floor F, a large reaction force from the vehicle floor F does not substantially occur, and therefore no external force in the tilting direction acts on the wheelchair 1. Therefore, the seated person does not feel uneasy.
Thus, by lowering the left and right step plates 51 and 51 to a position where they abut against the vehicle floor F as shown by the two-dot chain line in FIG. 11, the seated person can grip the steering handle H in an easy posture. In addition, the brake pedal can be operated.

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, the seated person first moves the left and right step plates 51 and 51 to the ascending end position by operating the step elevating switch at hand to the ascending side. 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. At this time, the interference with the rocker R is avoided because the step plates 51 and 51 are raised to the rising end position.
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 and rear wheel storage mechanism is operated to take out the front and rear wheels 8 and 9, and then the front and rear wheels 8 and 9 are grounded to 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.

In addition, after separating the wheelchair 1 from the seat moving device 100, the seated person operates the step lift switch at hand to lower the left and right step plates 51, 51 to the lower end position. In this case, assuming that there is a step D on the road surface L below the step plates 51 and 51 as shown in FIG. 3, the step plates 51 and 51 are in contact with the step D in the middle of lowering to the lower end position. Touch. When one or both of the step plates 51 and 51 come into contact with the step D when the seated person operates the step lift switch to the lower side to apply the lower side power to the left and right step plates 51 and 51, As in the case of contact with the vehicle floor F, the lowering of both the step plates 51 and 51 is restricted, so that a large rotational resistance is added to the screw shaft 55, and thereby each drive side member 81 of the joints 80 and 80. And the driven-side member 82 are in a state where the rotational power of the electric motor 54 is cut off and is not transmitted to the screw shaft 55.
As described above, when the left and right step plates 51, 51 ride on the step D, the power to the screw shafts 55, 55 is interrupted immediately after that, so that the reaction force from the step D acts on the wheelchair 1. Therefore, the seated person does not feel uneasy.
Further, when the left and right step plates 51, 51 reach the descending end position and the nuts 56, 56 contact the screw shaft base 73, the lowering of the nuts 56, 56 is restricted. A rotation resistance is added, and also in this case, the driving side member 81 of the joint 80 slides in the rotation direction with respect to the driven side member 82 to cut off the power of the electric motors 54 and 54.
Further, when the seat occupant releases the on / off operation of the step lift switch, the step plates 51 and 51 can be stopped at the rising end position and the falling end position, and any position between the rising end position and the falling end position can be set. It can be stopped at the height position.

According to the step device 50 of the present embodiment configured as described above, when the left and right step plates 51, 51 are lowered, the step plates 51, 51 hit the vehicle floor F just before reaching the lower end height. When it comes into contact or abuts against the road surface step D, the power of the electric motors 54 and 54 is cut off and the rotation of the screw shafts 55 and 55 is stopped. Thus, no reaction force is received from the vehicle floor F or the road surface step D, and therefore no reaction force in the backward tilt direction acts on the wheelchair 1, so that the seated person does not feel uneasy.
Further, immediately after the step plates 51 and 51 abut against the vehicle floor F and abut against the road surface step D or the like, the driving force of the electric motors 54 and 54 is cut off and the vehicle floor F of the step plates 51 and 51 is cut off. Since the pressing force against the same is removed, these scratches can be prevented.
Further, when the left and right step plates 51, 51 reach the descending end and the nuts 56, 56 abut against the screw shaft base 73, respectively, and their lowering is restricted, this also causes a large rotational resistance against the screw shafts 55, 55. Therefore, the driving side member 81 of the joint 80 moves against the compression spring 83 and slides with respect to the driven side member 82, whereby the power of the electric motors 54 and 54 is cut off.
As described above, when the step plates 51 and 51 come into contact with the vehicle floor or the like in the middle of the lowering, or reach the lowering end, even if the seated person keeps operating the step up / down switch to the lowering side, Accordingly, the power of the electric motors 54 and 54 is cut off and does not act on the step plates 51 and 51, so that the motor lock state of the electric motors 54 and 54 can be reduced.
In addition, when a seated person cancels | releases ON operation of a step raising / lowering switch, step board 51,51 can be stopped in a raise end position and a fall end position, and arbitrary between a rise end position and a fall end position is also possible. It can be stopped at the height position.
Further, in the illustrated step device 50, the power of the elevating mechanism is cut off when the lowering operation of the step plates 51, 51 is restricted, and an obstacle interferes with part of the lower surface of the step plates 51, 51. Even so, the structure can be operated reliably. On the other hand, for example, when a pressure sensor or a micro switch is attached to the lower surface (back surface) of the step plate, and these operations are configured to detect interference with obstacles at the step position, these sensors are activated. When an obstacle interferes with a position that is not allowed to move, the operation of the lifting mechanism cannot be interrupted. Therefore, in this case, another mechanism is required for reliably operating this type of sensor not only when the obstacle is interfered with, but also with the entire step plate. The illustrated step device 50 has a configuration in which the lifting mechanism is stopped by the rotational resistance to the screw shaft that is generated when the step plates 51 and 51 are in the descending movement restricted state. Therefore, the step plate is not required separately. When the lowering operation of 51, 51 stops, the power transmission of the elevating mechanism can be reliably interrupted.

Various modifications can be made to the embodiment described above. For example, the driving side member 81 and the driven side member 82 are configured to transmit power by meshing between the engaging projection 81c and the receiving projection 82c and cut off power by disengaging each other. Instead of the protrusion 81c and the receiving protrusion 82c, a plurality of steel balls spring-biased on the driven member side are arranged around the rotation axis, and a hemispherical engagement hole is provided in the drive side member to engage each steel ball. When the rotational resistance of a certain level or more is applied to the screw shaft, each steel ball is separated from the engagement hole against the spring biasing force to rotate the driving side member relative to the driven side member to It is good also as a structure which interrupts | blocks. In this case, as illustrated above, it is not necessary to support the drive side member so as to be axially displaceable with respect to the output shaft of the electric motor.
Moreover, although the wheelchair 1 of the form which can be moved between the vehicle interior and exterior by the seat moving apparatus 100 and can also be used as a vehicle seat is illustrated, it can be similarly applied to a wheelchair used independently of the vehicle.
On the contrary, the wheelchair 1 in the form that can be separated from the seat moving device 100 and used alone on the road surface L is illustrated, but when the wheelchair is not separated from the seat moving device 100 and is used exclusively for a vehicle seat. Can be applied similarly.
Moreover, although the vehicle floor F and the level | step difference D of the road surface L were illustrated as an obstruction which controls the descent | fall operation | movement of the step boards 51 and 51, For example, the same effect | action also about other obstructions, such as a level | step difference (stairs) of a building floor surface, for example. An effect can be obtained.

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 the step apparatus of embodiment. It is a front part of a wheelchair, Comprising: It is a side view of the step device of an embodiment. It is a side view of the raising / lowering mechanism of the step apparatus which concerns on embodiment of this invention. It is a step device concerning an embodiment of the present invention, and is an exploded perspective view of a screw shaft upper part and its circumference. It is a side view which shows the engagement state of the drive side member of a joint, and a driven side member. This figure shows the time of power transmission on the step-up side. It is a side view which shows the engagement state of the drive side member of a joint, and a driven side member. This figure shows the time of power transmission on the step descending side. It is a side view which shows the state where the rotational resistance was added to the screw shaft and the drive side member and the driven side member of the joint slipped in the rotation direction. It is a side view which shows the connection procedure with respect to the seat movement apparatus of a wheelchair. It is a side view which shows the state which moves the wheelchair connected with the seat moving apparatus between vehicle interior and exterior. This figure has shown the state which looked at the driver's seat from the vehicle front. FIG. 11 is a view taken in the direction of the arrow (11) in FIG. 10 and shows a state in which the wheelchair is moved to the driver seat position as viewed from the passenger seat side (the vehicle left side).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheelchair 7 ... Seat frame, 7a ... Engagement recessed part, 7b, 7c ... Side surface 50 ... Step apparatus 51 ... Step board 52 ... Elevating mechanism 53 ... Fixed base 54 ... Electric motor 55 ... Screw shaft, 55c ... Drive shaft part 56 ... Nut 57 ... Elevating base 70 ... Motor bracket 80 ... Joint 81 ... Drive side member 81c ... engagement projection, 81ca ... engagement surface, 81cb ... tilt surface 82 ... driven side member 82c ... receiving projection, 82ca ... engagement Surface, 82cb ... inclined surface 83 ... compression spring 100 ... seat movement device 101 ... connection base M ... vehicle L ... road surface D ... step

Claims (1)

A step device provided at a front portion of a wheelchair and provided with a step plate on which a seated person sitting on the wheelchair puts his / her foot, and an elevating mechanism for raising and lowering the step plate,
The elevating mechanism has an electric motor as a drive source, a screw shaft rotated by the electric motor, and a nut meshed with the screw shaft, and supports the step plate to the nut and rotates the screw shaft. The step plate is moved up and down by the vertical movement of the nut by
The screw shaft is connected to the output shaft of the electric motor via a joint, and the joint includes a driving side member and a driven side member divided into two in the power transmission direction,
During the operation of lowering the step plate, when the step plate interferes with an obstacle and the lowering operation is restricted, the screw side causes the rotational resistance received by the screw shaft to drive the drive side member. A stepping device configured to cut off the power of the electric motor by separating them in the rotation direction.

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