JP2014024375A - Step lifting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a step lifting apparatus capable of ascending and descending a step.SOLUTION: A step lifting apparatus 1 includes a pair of right and left screw wheels 20. The pair of right and left screw wheels 20 are respectively rotated in synchronization with each other in opposite directions by a travel motor 10. The step lifting apparatus 1 rotates the screw wheels 20 in a state in which rotation axes 13 of the screw wheels 20 intersect with each other in an extending direction of a step nose of a stair-shaped step. Consequently, the step lifting apparatus 1 ascends and descents the step with the screw wheels 20 engaged with the step nose of the step.

Description

  The present invention relates to a step elevation device that can raise and lower a step.

  A wheelchair, a loading platform, and the like travel on a transport path when transporting a person or a load. When there is a step in the transport path, it is necessary to raise and lower the step. As a wheelchair for raising and lowering a step, for example, Patent Document 1 discloses a wheelchair equipped with a caterpillar. A wheelchair that runs on a step such as a staircase by a caterpillar is unstable because the caterpillar is slippery with respect to the step. Therefore, in the wheelchair of Patent Document 1, a deployment plate is provided on the caterpillar, and the deployment plate is brought into close contact with the stepped surface of the step to prevent the caterpillar from slipping.

JP 2000-14711 A

  In the wheelchair of Patent Document 1, the weight of the vehicle body is added to the caterpillar when moving up and down the step. At this time, if the weight of the vehicle body is increased, the contact area between the caterpillar and the step is small, and there is a risk of sliding off. Further, although the projection is provided on the caterpillar, a large local force is applied to the projection, so that the projection may be damaged.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a step lifting device that can lift and lower a step.

  In order to solve the above-mentioned problems, a step lifting device of the present invention is provided at least in a pair on the left and right sides of a vehicle body part and the vehicle body part, and is supported by the vehicle body part so as to be rotatable and immovable in the rotation axis direction. A spiral member; and a rotational drive means for rotating the spiral member, wherein the rotational drive means causes the rotational axis of the pair of left and right spiral members to intersect with the extending direction of the step nose of the conveyance path. The pair of spiral members are rotated in opposite directions, and the vehicle body part moves up and down the step when the spiral member rotates and meshes with the step. Thereby, the level | step difference raising / lowering apparatus which can raise / lower a level | step difference can be provided.

  In addition, the present invention is characterized by including a pitch variable mechanism that changes a helical pitch of the spiral member. The spiral member of the present invention is provided in four in the vehicle body, and the rotation driving means can independently rotate the four spiral members, and the four spiral members in the vehicle body. It is characterized by comprising steering means for turning each independently.

  Further, the vehicle body portion of the present invention is provided with a guide member on the front side in the traveling direction of the vehicle body portion, and the guide member abuts on the step and urges the vehicle body portion to the raised posture of the step. It is characterized by that. Further, the guide member of the present invention is a tapered spiral member, and the rotation axis of the tapered spiral member is inclined upward with respect to the traveling direction of the vehicle body.

  The present invention can provide a step elevation device that can raise and lower a step.

The side view which shows the level | step difference raising / lowering apparatus which concerns on embodiment of this invention. The front view of the level | step difference raising / lowering apparatus of FIG. The AA sectional view of Drawing 1 showing the screw wheel of a level difference raising and lowering device. The side view which shows the effect | action of a level | step difference raising / lowering apparatus. The side view which shows the effect | action of a level | step difference raising / lowering apparatus. The side view which shows the effect | action of a level | step difference raising / lowering apparatus. The side view which shows the effect | action of a level | step difference raising / lowering apparatus. The side view which shows the level | step difference raising / lowering apparatus which concerns on the example 1 of a change of this invention. The side view which shows the level | step difference raising / lowering apparatus which concerns on the modification 2 of this invention. The side view which shows the level | step difference raising / lowering apparatus which concerns on the modification 2 of this invention. The side view which shows the level | step difference raising / lowering apparatus which concerns on the modification 2 of this invention. The side view which shows the level | step difference raising / lowering apparatus which concerns on the modification 3 of this invention. The side view which shows the level | step difference raising / lowering apparatus which concerns on the modification 4 of this invention. The fragmentary sectional view which shows the screw wheel which concerns on the modification 5 of this invention. The fragmentary sectional view which shows the screw wheel which concerns on the modification 6 of this invention.

Hereinafter, a step lifting device according to an embodiment will be described with reference to the drawings.
The vehicle body portion of the step lifting device 1 shown in FIG. 1 includes an upper frame 3, a lower frame 4, a front frame 5 and a rear frame 6. The upper frame 3 and the lower frame 4 are rectangular flat plates having the same size. The upper frame 3 and the lower frame 4 are connected by a front frame 5 and a rear frame 6 so as to maintain a predetermined interval in parallel. The front frame 5 and the rear frame 6 are prisms. Two front frames 5 and six rear frames 6 are used in this embodiment. As shown in FIGS. 1 and 2, the two front frames 5 connect the upper frame 3 and the lower frame 4 at the left and right ends of the front ends of the upper frame 3 and the lower frame 4. The two rear frames 6 connect the upper frame 3 and the lower frame 4 at both left and right ends of the rear ends of the upper frame 3 and the lower frame 4.

  Between the upper frame 3 and the lower frame 4, a battery 8 is disposed in the approximate center of the vehicle body. Further, a traveling motor 10 is disposed between the upper frame 3 and the lower frame 4. The traveling motor 10 is a drive source that supplies power for traveling of the step lifting device 1. The travel motor 10 is disposed behind the battery 8. The travel motor 10 is provided with an output shaft 11. A drive belt 12 is wound around the output shaft 11 so that the output of the travel motor 10 can be transmitted. The drive belt 12 is suspended below the lower frame 4 through an opening (not shown) provided in the lower frame 4. The drive belt 12 is wound around the rotary shaft 13. The rotating shaft 13 is a rotating shaft extending in the front-rear direction of the step lifting device 1. The front end of the rotating shaft 13 is rotatably supported by a front support portion 15 provided so as to protrude downward from the front end of the lower frame 4. The rear end of the rotating shaft 13 is rotatably supported by a rear support portion 16 that protrudes downward from the rear end of the lower frame 4.

  A movable plate 17 is provided on the front support portion 15 side of the rotary shaft 13. The movable plate 17 has a stepped disk shape. The movable plate 17 is movable in the longitudinal direction of the rotating shaft 13. A fixed plate 18 is provided in front of the drive belt 12 on the rear support 16 side of the rotary shaft 13. The fixed plate 18 has a thin disk shape. The front and rear positions of the fixed plate 18 are fixed so as not to move in the longitudinal direction of the rotary shaft 13. A screw wheel 20 is disposed as a spiral member on the rotating shaft 13 between the movable plate 17 and the fixed plate 18. Both front and rear ends of the screw wheel 20 are provided in contact with the movable plate 17 and the fixed plate 18, respectively. The screw wheel 20 is always positioned in contact with the fixed plate 18 and cannot move in the direction of the rotation axis of the rotation shaft 13. The screw wheel 20 has a spiral shape like the coil spring. The screw wheel 20 is made of metal. As shown in FIG. 3, the rotating shaft 13 is disposed at the same position as the central axis of the screw wheel 20. A spoke 20 </ b> A that extends toward the rotation shaft 13 is provided on the inner peripheral surface of the screw wheel 20. The spoke 20A is formed of a stretchable metal. The screw wheel 20 is connected and supported to the rotary shaft 13 by spokes 20A. The rotation of the rotary shaft 13 is such that the same amount of rotation is transmitted to the screw wheel 20 by the spoke 20A.

  A pressing portion 22 is disposed on the front support portion 15 side of the movable plate 17. The pressing portion 22 has a substantially spherical shape. The pressing portion 22 biases the movable plate 17 from the front support portion 15 side to the fixed plate 18 side. The pressing portion 22 is for urging and moving the movable plate 17 in the longitudinal direction of the rotary shaft 13. A pitch changing rod 23 is connected to the pressing portion 22. The pitch changing rod 23 is a rod-like member connected so as to extend upward from the pressing portion 22. The pitch changing rod 23 passes through an opening (not shown) of the lower frame 4 and an opening (not shown) of the upper frame 3 so as to protrude upward from the upper frame 3. A pivot pin 24 is connected to a position slightly above the lower frame 4 of the pitch changing rod 23. The pivot pin 24 is a pin fixed to the lower frame 4. The longitudinal direction of the pivot pin 24 extends parallel to the lower frame 4. The pivot pin 24 is arranged in a direction orthogonal to the longitudinal direction of the pitch changing rod 23. The pitch changing rod 23 is rotatably connected to the shaft support pin 24. Therefore, the pitch changing rod 23 can be rotated back and forth around the pivot pin 24.

  As shown in FIG. 2, the travel motor 10, the output shaft 11, the drive belt 12, the rotating shaft 13, the front support portion 15, the rear support portion 16, the movable plate 17, the fixed plate 18, the screw wheel 20, the spoke 20A, The pressing portion 22, the pitch changing rod 23, and the pivot pin 24 are provided in a pair of left and right on the step lifting device 1. The pair of left and right screw wheels 20 are arranged symmetrically so that the spiral direction is opposite. Note that the travel motor 10, the output shaft 11, the drive belt 12, and the rotation shaft 13 of the present embodiment constitute a rotation drive unit that rotates the screw wheel 20. The movable plate 17, the fixed plate 18, the pressing portion 22, the pitch changing rod 23, and the pivot pin 24 constitute a pitch variable mechanism that changes the pitch of the screw wheel 20.

  Further, the step lifting device 1 is provided with a guide member on the front side in the traveling direction of the vehicle body. The guide member includes a guide motor 25, an output shaft 25A, a rotation transmission belt 25B, a protruding rod 26, a rotation shaft 26A, and a guide roller 27. The guide motor 25 is disposed on the right side of the front center between the upper frame 3 and the lower frame 4. A rotation transmission belt 25B is wound around the output shaft 25A of the guide motor 25. The rotation transmission belt 25 </ b> B extends to the front ends of the upper frame 3 and the lower frame 4. The rotation transmission belt 25 </ b> B is wound around the rotation shaft 26 </ b> A at the base end of the protruding rod 26. The rotation transmission belt 25B transmits the output of the guide motor 25 to the rotation shaft 26A as rotation. The rotation shaft 26 </ b> A is connected to the protruding rod 26. The protruding rod 26 is a member that tilts up and down in front of the vehicle body with the rotation shaft 26A as a central axis. A pair of guide rollers 27 is rotatably connected to the tip of the protruding rod 26. As shown in FIG. 2, the guide roller 27 is disposed at the center of the left and right of the step lifting device 1. The guide roller 27 is movable up and down by the protruding rod 26. That is, the guide roller 27 moves up and down by driving the guide motor 25. The guide roller 27 is maintained without changing the vertical position in a state where the guide motor 25 is stopped.

Next, traveling of the step lifting device 1 of this embodiment will be described.
An operator who operates the step lifting device 1 drives a pair of left and right traveling motors 10 of the step lifting device 1. At this time, the pair of left and right traveling motors 10 are rotated in opposite directions. Then, the driving force of the travel motor 10 rotates the rotating shaft 13 from the output shaft 11 via the driving belt 12. The pair of left and right rotating shafts 13 are rotated in opposite directions. When the rotating shaft 13 is rotated, the screw wheel 20 is also rotated through the spoke 20A. Then, the pair of left and right screw wheels 20 are rotated in opposite directions. Then, the rotational force of the pair of left and right screw wheels 20 acts to advance or reverse the step lifting device 1 as an archimedian screw. Further, if the rotation amounts of the left and right traveling motors 10 are different, the rotation amounts of the pair of left and right screw wheels 20 differ. Therefore, the step lifting device 1 can change the course to the left and right instead of going straight in the front-rear direction. And an operator runs the level | step difference raising / lowering apparatus 1 in a desired direction on a conveyance path.

  Next, the raising / lowering of the level | step difference by the level | step difference raising / lowering apparatus 1 is demonstrated. Here, a conveyance path provided with a staircase composed of six steps S1 to S6 shown in FIG. 4 will be described as an example. When ascending the stairs with the step lifting device 1, the operator first moves the step lifting device 1 to a position orthogonal to the stair nosing as shown in FIG. In FIG. 4, the axial direction of the rotary shaft 13, that is, the front-rear direction of the step lifting device 1, intersects with the extending direction of the step nose of each step S <b> 1 to S <b> 6 of the staircase. Here, an operator adjusts the pitch of the spiral of the screw wheel 20 of the step lifting device 1 according to the distance of the nose of each step S1 to S6 of the staircase. Specifically, the operator tilts the pitch changing rod 23 in the front-rear direction. The pitch changing rod 23 rotates back and forth around the pivot pin 24. Then, the pressing portion 22 at the lower end of the pitch changing rod 23 moves in the longitudinal direction of the rotating shaft 13. When the pressing portion 22 moves, the movable plate 17 also moves in the longitudinal direction of the rotating shaft 13. Thereby, the space | interval of the movable plate 17 and the fixed plate 18 changes. When the distance between the movable plate 17 and the fixed plate 18 changes, the screw wheel 20 expands and contracts in the front-rear direction, and the helical pitch changes. And it adjusts so that the integral multiple of the pitch of a spiral may become equal to the distance between the noses of a staircase. In the present embodiment, in the initial state shown in FIG. 4, twice the spiral pitch is substantially equal to the distance between the stair nosings (see FIG. 7), so the adjustment work is omitted.

  Next, an operator runs the level | step difference raising / lowering apparatus 1 so that it may approach a staircase. Then, the guide roller 27 is brought into contact with the stairs as shown in FIG. In the present embodiment, the guide roller 27 contacts the nose of step S3. Then, the operator further moves the step lifting device 1 forward. Then, as shown in FIG. 5, when the guide roller 27 rides on step S <b> 3, the step lifting device 1 slightly rises in front of the vehicle body and assumes a rising posture. Here, the operator drives the guide motor 25. Then, the output shaft 25A of the guide motor 25 rotates, and the rotation shaft 26A rotates through the rotation transmission belt 25B. Then, the protrusion rod 26 rotates toward the lower side of the step lifting device 1 around the rotation shaft 26A. When the protruding rod 26 rotates downward, the guide roller 27 is supported in step S3, so that the step lifting device 1 is further raised as shown in FIG. Then, the operator drives the traveling motor 10 to advance the step lifting device 1. The step lifting device 1 advances while rotating in a state where the pair of left and right screw wheels 20 are rotated in reverse from each other and sequentially engaged from step S1 of the staircase. Then, as shown in FIG. 7, the vehicle travels while being raised by the screw wheel 20 from step S1 to step S6.

  The step lifting device 1 travels on a step (stairs) as described above. Further, when descending the step (stairs), the stairs are descended in the reverse procedure to the above-described step (step). That is, the operator first causes the step lifting device 1 to travel (retract) so that the step lifting device 1 faces the step S6 of the staircase. At this time, an operator arrange | positions the level | step difference raising / lowering apparatus 1 in the direction where the rotating shaft 13 of the screw wheel 20 cross | intersects the nose of step S6. Then, the operator drives the traveling motor 10 in a reverse rotation to that at the time of ascent, and lowers the stairs so that the screw wheel 20 meshes with the steps S6 to S1 of the stairs as shown in FIG. When descending the stairs, the step (stair) may be lowered with the guide roller 27 of the step lifting device 1 in front.

This embodiment has the following effects.
(1) The level difference raising / lowering device 1 is provided with a pair of left and right screw wheels 20 on the vehicle body and is driven in the reverse direction by the traveling motor 10. As a result, the step lifting device 1 can move up and down the step (step) by rotating the pair of left and right screw wheels 20 in the opposite directions and moving forward and backward while the screw wheel 20 is engaged with the step. it can.
(2) The step lifting device 1 is provided with a variable pitch mechanism. Thereby, the pitch of the spiral of the screw wheel 20 can be changed even on the stairs where the distance between the noses is different, and the screw wheel 20 can be moved up and down.
(3) The step lifting device 1 is provided with a guide roller 27 that is movable up and down. The step-lifting device 1 can be brought into the rising posture by bringing the guide roller 27 into contact with the step (step). Therefore, it is easy to go up the step (stairs) with the step lifting device 1.

(4) The screw wheel 20 is disposed long in the front-rear direction of the step lifting device 1. The screw wheel 20 of the present embodiment has a spiral shape of approximately 10 turns. Therefore, even on stairs that are a plurality of steps, the screw wheel 20 straddles two or more stair nosings, so that it can travel stably.

The present invention is not limited to the above embodiment. Examples of modifications are described below.
O Although the level | step difference raising / lowering apparatus 1 of embodiment provided the left-right paired screw wheel 20, you may increase the number of the screw wheels 20 further. For example, as a modified example 1 as shown in a step lifting device 30 shown in FIG. In this case, the output shaft 11 of the travel motor 10 is disposed on the center side of the vehicle body. Then, the rotating shaft 13 is rotated by the drive belt 12 below the lower frame 4. The rotating shaft 13 is supported by two brackets 31 provided to hang downward from the lower frame 4. The rotating shaft 13 is supported by the front support portion 15 and the rear support portion 16. Then, the movable plate 17 is disposed between the front support portion 15 and the front bracket 31. Further, the movable plate 17 is disposed between the rear support portion 16 and the rear bracket 31. The front screw wheel 120 is disposed between the front support portion 15 and the front movable plate 17 so as to come into contact therewith. The rear screw wheel 120 is disposed between the rear support portion 16 and the rear movable plate 17 so as to come into contact therewith. The front and rear screw wheels 120 may be provided with a variable pitch mechanism as in the embodiment.

The four screw wheels 120 of Modification 1 may be configured to be independently rotatable. As a configuration in which the four screw wheels 120 are independently driven and steered, for example, in the step lifting device 40 of the modified example 2 shown in FIG. A shaft 11 and a drive belt 12 are provided. Each screw wheel 220 is provided to be steerable by the steering belt 41. The steering belt 41 is disposed on the lower surface of the upper frame 3. The steering belt 41 is connected to and driven by the output shaft 43 of the steering motor 42. The steering motor 42 is supported by a bracket 44 that hangs down from the lower surface of the upper frame 3 and a bracket 45 that connects the lower end of the bracket 44. The steering belt 41 turns the front screw wheel 220 including the front frame 5. Then, the steering belt 41 turns the rear screw wheel 220 including the rear frame 6 as shown in FIG. Since the four screw wheels 220 can rotate independently with respect to the upper frame 3 that is the vehicle body, the degree of freedom of travel of the step lifting device 40 can be improved. That is, the step lifting device 40 can be turned on the spot or moved in the lateral direction. In the step elevation device 40 of the second modification, the steering belt 41, the steering motor 42, and the output shaft 43 constitute steering means for independently turning the screw wheel 220. Further, as shown in FIG. 11, the step lifting device 40 rotates the front and rear screw wheels 220 in the same direction so that the screw wheel 220 can travel the step lifting device 40 like a tire such as an automobile. For example, in FIG. 11, when the front and rear screw wheels 220 are rotated counterclockwise in the drawing, the step lifting device 40 travels toward the front side. Thereby, compared with the case where the screw wheel 220 is driven as an Archimedian screw, the traveling capability of the step lifting device 40 can be greatly improved.

The guide member is not limited to the configuration of the guide roller 27 of the embodiment. For example, a screw wheel may be used as the guide member. 12 is provided with a guide frame 51 on the front side in the traveling direction of the vehicle body. The guide frame 51 is provided on the upper frame 3 so as to extend obliquely upward in the front direction. The guide frame 51 is provided with support portions 52 and 53 at the front and rear. The support portions 52 and 53 are orthogonal to the guide frame 51 and extend toward the floor. The support parts 52 and 53 are parallel to each other. A rotating shaft 55 is rotatably connected to the support portions 52 and 53. The rotation shaft 55 is parallel to the guide frame 51 and is inclined upward with respect to the traveling direction of the vehicle body. The rotation shaft 55 passes through the support portion 53 and is connected to the output shaft 25 </ b> A of the guide motor 25. The output shaft 25A can transmit the output (rotation) of the guide motor 25 to the rotation shaft 55. The rotating shaft 55 is provided with a tapered screw wheel 56. The tapered screw wheel 56 is rotatable together with the rotating shaft 55. The tapered screw wheel 56 is parallel to the guide frame 51. The spiral diameter of the tapered screw wheel 56 is set so as to decrease from the support portion 53 toward the support portion 52. When raising and lowering the stairs, the step lifting device 50 first meshes the tapered screw wheel 56 with, for example, steps S5 and S6 of the stairs. Then, the guide motor 25 is driven to rotate the tapered screw wheel 56. Then, the taper screw wheel 56 raises step S5 and step S6. And the level | step difference raising / lowering apparatus 50 raises the front of a vehicle body part by the taper screw wheel 56, and becomes a raise attitude | position. By using the taper screw wheel 56, the step lifting device 50 can be lifted, so that the step lifting device 50 can easily climb the stairs. The tapered screw wheels 56 are preferably provided in a pair on the left and right sides and synchronized so as to rotate in opposite directions.

The tapered screw wheel 56 as a guide member may be provided at the same height as the lower frame 4. For example, a step lifting device 60 shown in FIG. 13 as a fourth modification connects the guide frame 51 in front of the upper frame 3 and the lower frame 4. Further, the rotation shaft 55 is connected to the rotation shaft 13 provided through the front support portion 15 so as to be able to transmit the rotation. In this configuration, the tapered screw wheel 56 can first mesh with the steps S1-S4, which are lower in steps. Therefore, the front of the step lifting device 60 can be further raised, and the step lifting device 60 can be easily set in the rising posture. The rotating shaft 55 and the tapered screw wheel 56 are connected to the rotating shaft 13. Therefore, the taper screw wheel 56 can be rotated by the traveling motor 10, and the guide motor 25 can be abolished.

-The screw wheel 20 is not limited to the structure of embodiment and a modification. A caster may be provided on the outer peripheral surface of the screw wheel. For example, in the fifth modification shown in FIG. 14, the caster roller 71 and the caster wheel 72 are provided on the outer peripheral surface of the screw wheel 20. The caster wheel 72 protrudes from the outer peripheral surface of the screw wheel 20. The caster wheel 72 supports the caster roller 71 so as to be rotatable about the radial shaft from the rotary shaft 13. By providing the caster roller 71 on the outer peripheral surface of the screw wheel 20, the step lifting device 1 can reduce the frictional resistance with the stairs when the stairs are raised and lowered.
In addition, a ball caster may be configured by embedding a ball in the screw wheel 20 in a freely rotatable manner. For example, in the sixth modification shown in FIG. 15, the outer peripheral surface of the screw wheel 320 also receives a plurality of the recessed portions 81. The recessed portion 81 has an opening on the outer peripheral surface of the screw wheel 320. Then, the ball 82 is rotatably inserted into the recess 81 as a caster. Thereby, the screw wheel 320 can reduce friction with respect to steps such as stairs, and the step lifting device can easily move up and down stairs (steps). In addition, the number of the recessed parts 81 and the balls 82 is not limited to the example of FIG.

The screw wheel 20 may be covered with a cover. Instead of providing casters as in Modification 5 and Modification 6, by covering the screw wheel 20 with a cover, an increase in the number of parts can be suppressed, and wear can be reduced with a simple structure. The cover should be a cloth-like material. Then, oil may be applied to the cover.
O Guide members may be provided on both sides before and after the step lifting device. By providing the guide roller 27 of the step lifting device 1 of the embodiment also on the rear side, the step lifting device 1 can move up the stairs (step) without changing the direction, regardless of whether it travels forward or backward. Further, when the stairs (steps) are lowered, the stairs (steps) can be stably lowered by the guide rollers on both the front and rear sides.

○ The step lifting device may be used as a cargo bed. You may form the bed part for fixing the load conveyed on a vehicle body part. Further, the step lifting device may be provided integrally with the wheelchair. By providing a step lifting device at the lower part of the wheelchair, normal traveling can be performed with the wheelchair wheel. And when raising / lowering a level | step difference or a staircase, while using the level | step difference raising / lowering apparatus, while moving the action range of a wheelchair, it can move easily irrespective of a road surface shape.

1, 30, 40, 50, 60 Step lifting device 3 Upper frame 4 Lower frame 5 Front frame 6 Rear frame 8 Battery 10 Traveling motor 11, 25A, 43 Output shaft 12 Driving belt 13, 26A, 55 Rotating shaft 15 Front support 16 Rear support portion 17 Movable plate 18 Fixed plate 20, 56, 120, 220, 320 Screw wheel 20A Spoke 22 Pressing portion 23 Pitch change rod 24 Pivot support pin 25 Guide motor 25B Rotation transmission belt 26 Projection rod 27 Guide roller 31, 44, 45 Bracket 41 Steering belt 42 Steering motor 51 Guide frame 52, 53 Support part 71 Caster roller 72 Caster wheel 81 Recessed part 82 Ball

Claims (5)

The body part,
A spiral member that is provided at least in a pair on the left and right sides of the vehicle body, is supported by the vehicle body so as to be rotatable and immovable in the direction of the rotation axis;
Rotation driving means for rotating the helical member,
With the rotation axis of the pair of left and right spiral members intersecting the extending direction of the step nose of the conveyance path, the pair of left and right spiral members are rotated in opposite directions by the rotation driving means, and the spiral member is rotated. However, the step lifting device is characterized in that when the vehicle body moves forward and backward with respect to the step while being engaged with the step, the vehicle body portion moves up and down the step.   The step lifting device according to claim 1, further comprising a pitch variable mechanism that changes a pitch of the spiral of the spiral member. Four spiral members are provided on the vehicle body,
The rotation driving means is capable of independently rotating the four spiral members,
The step-lifting device according to claim 1, further comprising: a steering unit that independently turns the four spiral members with respect to the vehicle body portion. The vehicle body portion is provided with a guide member on the front side in the traveling direction of the vehicle body portion,
The step lifting device according to any one of claims 1 to 3, wherein the guide member abuts on a step to urge the vehicle body portion to a rising posture of the step. The guide member is a tapered spiral member;
The step-lifting device according to claim 4, wherein a rotating shaft of the tapered spiral member is inclined upward with respect to a traveling direction of the vehicle body portion.

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