JP2016222160A - Caster switching transport carriage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of being difficult to directly transport on the inside-outside of a dustproof area, without reloading a loading object in a transport carriage.SOLUTION: A caster switching transport carriage comprises a first caster device 12 having the predetermined number of wheels provided in a lower part of a loading space 11, a second caster device 30 provided in a lower part of a caster board 31a vertically movably arranged in a lower part of the loading space and having the predetermined number of wheels descendable up to a lower part than the wheels of the first caster device and a lifting device 20 for lifting the second caster device to the loading space, and the lifting device is constituted of a driving member 21 rotatably provided in the loading space and a link mechanism 40 for raising or lowering the second caster device by rotational direction of the driving member provided between the loading space and the second caster device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a caster switching transport cart that includes two sets of caster devices under a loading platform, and switches caster devices to be used according to a traveling path.

When traveling between areas with different cleanliness using a transport cart, to prevent dust adhering to the transport cart caster from scattering within the dust-proof area, it can be replaced with a dedicated transport cart that can run in the dust-proof area. There are measures, but it took time to transship.
As a conventional technology that eliminates the hassle of transshipment, a two-stage caster is provided on the lower surface of the loading platform on which the object is loaded, and the piston of the gas cylinder is made to protrude by a high-pressure gas stored in a sealed manner in a mechanism that switches the caster up and down. There is a transport cart that employs a gas drive mechanism that maintains the exit state (see, for example, Patent Document 1).
On the other hand, in order to capture the dust adhering to the caster, there is one in which the dust attached to the side is captured by the dust receiving mechanism attached to the side (for example, the tip attached to the side of the caster is scraped with a sharp edged jig). Patent Document 2).

Japanese Patent Laid-Open No. 2004-26026 Japanese Utility Model Publication No. 5-44744

With a two-stage caster switching mechanism that employs a gas drive mechanism such as Patent Document 1, it is difficult to adjust the lifting speed at the time of switching. There was a problem that the risk of damaging things could not be eliminated.
On the other hand, in the technology for capturing caster deposits as in Patent Document 2, the dust capture range is local, and the dust fall that could not be scraped off with a spatula or adhered to other than the ground contact surface of the caster It was difficult to capture the fall of dust.
Even if the configuration of Patent Document 1 is combined with the configuration of Patent Document 1, it cannot supplement the fall of dust that could not be scraped off with a spatula, or the fall of dust attached to other than the ground contact surface of the wheel. There was a problem.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a caster switching transport cart that can suppress a shock at the time of caster switching and can safely transport a load such as precision parts.
Furthermore, it aims at obtaining the caster switching transport cart which can prevent the fall of the dust adhering to the vicinity of a wheel reliably.

A caster switching transport cart according to the present invention is provided at a lower portion of a first caster device having a predetermined number of wheels provided at a lower portion of a loading platform and a caster board disposed at the lower portion of the loading platform so as to be vertically movable. A second caster device having a predetermined number of wheels that can be lowered below the wheels of the first caster device; and a lifting device that raises and lowers the second caster device relative to the loading platform, The elevating device raises or lowers the second caster device according to the rotation direction of the drive member provided between the cargo bed and the second caster device. And a link mechanism for lowering.
Further, in the above-described caster switching transport carriage, a dust receiving member that is movably provided at a lower portion of the caster board and prevents the foreign matter adhering to the wheels of the first caster device from dropping onto the floor surface, and the dust receiver The member is retracted when the wheel of the first caster device is in contact with the floor surface, the wheel of the second caster device is grounded, and the wheel of the first caster device is lifted from the floor surface In this state, a dust receiving member moving device for moving the first caster device so as to advance to the lower part of the wheel is provided.

In the caster switching transport cart according to the present invention, the first caster device having a predetermined number of wheels provided in the lower part of the cargo bed and the lower part of the caster board disposed in the lower part of the cargo bed so as to be movable up and down. A second caster device having a predetermined number of wheels that can be lowered below the wheels of the first caster device, and an elevating device that raises and lowers the second caster device relative to the loading platform, The lifting device ascends the second caster device by a drive member provided rotatably on the cargo bed and a rotation direction of the drive member provided between the cargo bed and the second caster device. In addition, since it is configured with a link mechanism that lowers, the impact at the time of caster switching is suppressed, and a load such as a precision part can be transported safely.
Further, in the above-described caster switching transport carriage, a dust receiving member that is movably provided at a lower portion of the caster board and prevents the foreign matter adhering to the wheels of the first caster device from dropping onto the floor surface, and the dust receiver The member is retracted when the wheel of the first caster device is in contact with the floor surface, the wheel of the second caster device is grounded, and the wheel of the first caster device is lifted from the floor surface By providing the dust receiving member moving device that moves the first caster device so as to advance to the lower part of the wheel in the state, it is possible to reliably prevent the dust adhering to the vicinity of the wheel from falling. Therefore, it is possible to prevent the adhered dust from falling onto a floor surface such as a clean room.

It is a side view which shows notionally the principal part of the caster switching transport trolley | bogie which concerns on Embodiment 1 and 2 of this invention, and has shown the state at the time of driving | running | working in a dust-proof area. It is a side view which shows notionally the principal part of the caster switching conveyance trolley | bogie which concerns on Embodiment 1 and 2 of this invention, and has shown the state at the time of driving | running | working outside a dust-proof area. It is a figure which illustrates notionally operation | movement of the raising / lowering mechanism shown by FIG. It is a figure which shows notionally the principal part of the support mechanism of the rotating shaft shown in FIG. 1, and a traverse plate locking mechanism, (a) is a perspective view, (b) is a figure which shows the shape of a plate. It is a figure which illustrates notionally the caster dust receiving mechanism shown by FIG. 1 in the caster switching conveyance trolley | bogie which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
1 and 2 are side views conceptually showing the main part of a caster switching transport cart according to Embodiments 1 and 2 of the present invention. FIG. 1 shows a state during traveling in a dust-proof area, and FIG. The state during traveling outside the dustproof area is shown. FIG. 3 is a diagram conceptually illustrating the operation of the lifting mechanism shown in FIG. 4A and 4B are diagrams conceptually showing main parts of the rotating shaft support mechanism and the traverse plate lock mechanism shown in FIG. 1, wherein FIG. 4A is a perspective view and FIG. 4B is a diagram showing the shape of the plate. . In addition, the same code | symbol is attached | subjected to the same member and part.
In the figure, a caster switching transport cart includes a load carrier 11 on which a load is placed, and a first caster device 12 having a total of four wheels 12b provided at four corners of the lower portion of the load carrier 11 via caster shafts 12a, respectively. The four wheels on which the ground contact position of the wheels is lowered below the wheels 12b of the first caster device 12 with respect to the caster board 31a provided in the lower part of the loading platform 11 via the lifting device 20 so as to be movable up and down. And a second caster device 30 having 31b. A hand pushing member 13 made of a pipe material is erected on the rear surface of the upper surface of the loading platform 11 (right side in FIG. 1).

In addition, the basic function of the part containing the loading platform 11, the 1st caster apparatus 12, and the hand pushing member 13 installed in the upper surface back of the loading platform 11 is the same structure as a general conveyance cart. In addition, the first caster device 12 is used when used outside the dustproof area, and the second caster device 30 is used inside the dustproof area.
The elevating device 20 extends in the front-rear direction and is rotatably supported at the center in the left-right direction (the front-rear direction with respect to the paper surface of FIG. 1) on the lower surface of the loading platform 11, and the screw groove 21a (see FIG. And a rotary shaft 21 as a driving member provided so that the rear end thereof is exposed to the outside of the cargo bed, and a rotary shaft that is detachably connected from the outside of the cargo bed 11 to the rear end portion of the rotary shaft 21. 21 and a link mechanism 40 provided between the loading platform 11 and the second caster device 30 so as to raise or lower the second caster device 30 depending on the rotation direction of the handle 22. Has been.

As will be described in detail later, the rotary shaft 21 is restricted from moving in the axial direction during normal times including when the lifting device 20 is used, and is caster dust during traveling by the second caster device 30 described in the second embodiment. When operating the receiving mechanism 50, it is comprised so that it can move to an axial direction.
The link mechanism 40 is crossed in an X shape when viewed from the side, and a pair of connecting members 41A and 41B that are pivotally coupled to each other by a shaft 42 provided on the cross portion are connected to the left side of the loading platform 11. A pantograph-type expansion / contraction device provided symmetrically on the right side and the right side is used. On the front side (left end side in the drawing) of the pair of left and right connecting members 41, one end of the connecting member 41A located at the lower side is placed on either side by a shaft 43a provided at the front part of the caster board. The left and right sides of the connecting member 41B, which is pivotally supported, are pivotally supported by a shaft 43b provided at the front portion of the frame at the bottom of the loading platform.

  Then, on the rear side (right end side in the figure) of the pair of left and right connecting members 41, the other end of the connecting member 41A located on the upper side is provided on a common transverse plate 44 (shown in FIG. 3). Each of the transverse plates 44 is pivotally supported so as to be rotatable with respect to the omitted bearings, and the transverse plate 44 can be slid only in the front-rear direction along a guide rail (not shown) provided on the frame below the loading platform. Is engaged. The other end of the connecting member 41B located at the lower part is engaged with a roller 45 along a guide rail (not shown) provided at the frame rear part of the caster board 31a so as to be movable only in the front-rear direction. ing.

  As shown in FIG. 3, the traversing plate 44 that is slidably engaged with the loading platform 11 is provided with a meshing portion 44 a that can engage with a screw groove 21 a provided on the rotary shaft 21 at the center thereof. And is engaged with a screw groove 21a of a rotating shaft 21 installed in the lower part of the loading platform 11 in a rotationally movable region A, and a handle 22 connected to the rotating shaft 21 is rotated to rotate in the front-rear direction on the lower surface portion of the loading platform 11. The link mechanism 40 can be expanded and contracted in the vertical direction. A ring-shaped locking member 21c used for restricting movement in the axial direction is fixed to the outer peripheral surface of the rear end portion of the rotating shaft 21. A rotating shaft movement restricting portion 70 is provided at the insertion portion of the rotating shaft 21 at the rear end portion of the loading platform 11 so as to support a right side surface in the drawing of the locking member 21c and receive a load in the thrust direction. Yes.

The rotating shaft movement restricting portion 70 is provided on the right side of the insertion portion of the rotating shaft 21 at the rear end portion of the loading platform 11, supports the right direction of the locking member 21 c, and receives two thrust plates 71 having the same shape in the thrust direction. And a plate fixing guide 72 that is provided on the frame at the rear end of the loading platform 11 and holds the two plates 71 in a removable manner. As shown in FIG. 4B, the plate 71 is provided with a U-shaped notch 71a having an arc larger than the outer diameter of the rotating shaft 21 and smaller than the outer diameter of the locking member 21c. The locking member 21c is supported by inserting the two plates 71 into the plate fixing guide 72 from above, and the portion of the locking member 21c of the rotating shaft 21 can be pulled out rearward in the axial direction if it is removed. Yes. Incidentally, the thrust load in the left direction of the rotation shaft is held by supporting the locking member 21d fixed to the right side at the insertion portion of the front rotation shaft movement restriction plate 73 provided in front of the loading platform 11. .
In addition, the stopper 14 is provided in the caster shaft 12a of the four corners which couple | bonds the loading platform 11 and the wheel 12b of a caster, The maximum descent | fall area of the caster board 31a is restrict | limited.
The other members and parts shown in FIGS. 1, 2, and 4 will be described in the second embodiment.

  Next, the operation of the first embodiment configured as described above will be described. First, when traveling outside the dust-proof area, the first caster device 12 is used in the state shown in FIG. In the state of FIG. 2, the traversing plate 44 of the link mechanism 40 is at the rear end portion in the moving direction, and the connecting member 41 is contracted in the vertical direction. The wheel 31b is levitated from the floor F by being lifted to the lower part. Then, after traveling outside the dust-proof area by the wheels 12b of the first caster device 12, when entering the dust-proof area, the transport cart is stopped in an appropriate area provided at the boundary portion that divides the inside and outside of the dust-proof area. Then, the handle 22 is rotated rightward to rotate the rotating shaft 21 clockwise. A meshing portion 44a of the traversing plate 44 is engaged with the screw groove 21a of the rotating shaft 21, and when the rotating shaft 21 is rotated in the clockwise direction in FIG. 3, the driving is performed to move the traversing plate 44 leftward in the figure. Power works.

  Since the rotation shaft 21 is restricted from moving in the right direction of the drawing in the drawing in the axial direction by a rotation shaft movement restricting portion 70 provided at the rear end portion of the loading platform 11, the traversing plate 44 is in front of the loading platform 11 (see FIG. 3), the connecting member 41 (41A, 41B) extends in the vertical direction, and the caster board 31a is pushed down. When the lower surface of the caster board 31a is pushed down until it comes into contact with the stopper 14, the wheel 31b of the second caster device 30 is pushed downward from the ground contact surface of the wheel 12b of the first caster device 12, and as a result, FIG. As shown in FIG. 1, the loading platform 11 is lifted and the first caster device 12 is lifted from the floor surface F, so that the vehicle can travel by the wheels 31 b of the second caster device 30. The handle 22 is detachable with respect to the rotating shaft 21 and may be removed from the rotating shaft 21 and held in a receiving portion (not shown) provided in the lower part of the loading platform 11 when it becomes an obstacle during traveling. The handle 22 may be folded.

  Until the wheel 31b of the second caster device 30 is grounded, the load on the handle 22 is small due to the gravity acting on the second caster device 30 including the caster board 31a. Since it is necessary to raise the load in addition to the load of the loading platform 11 and the first caster device 12 after the ground contact with the floor F, the thrust load acting in the axial direction with respect to the rotating shaft 21 is supported. For this reason, the locking member 21c, the rotation shaft movement restricting portion 70, and the like that restrict the movement in the axial direction acting on the rotation shaft 21 are required to have a structure that can withstand a corresponding load.

  On the other hand, in order to switch the second caster device 30 from the first caster device 12 to the first caster device 12 in order to run the transport cart from the dustproof area to the outside of the dustproof area again, the handle 22 is rotated to the left and the link mechanism 40 is moved. 2 on the opposite side, the caster board 31a is lifted, and the wheel 31b attached to the caster board 31a is lifted above the position of the wheel 12b of the first caster device 12, and in the state shown in FIG. The traveling by the wheel 12b of one caster device 12 becomes possible.

  The caster switching transport cart according to the first embodiment of the present invention includes the first caster device 12 having the four wheels 12b provided at the lower four corners of the loading platform 11 as described above, and the lifting device 20 with respect to the loading platform 11. And a second caster device 30 having four wheels 31b whose wheels can be lowered to a position lower than the first caster device, and the lifting device 20 is turnable on the loading platform 11. A rotary shaft 21 having a screw groove 21a as a provided drive member, a detachable handle 22 for rotating the rotary shaft, and the second caster device 30 is raised or lowered depending on the rotation direction of the handle. The link mechanism 40 is provided between the loading platform 11 and the second caster device 30.

  According to the first embodiment configured as described above, the second caster device 30 is provided with the first caster device 12 via the lifting device 20 including the link mechanism 40 using a pantograph type expansion and contraction device. The first caster device 12 and the second caster device 30 are connected to the loading platform 11 and switched between the first caster device 12 and the second caster device 30 by manually rotating the rotary shaft 21 provided with the screw groove 21a with the detachable handle 22. Therefore, the impact at the time of caster switching is suppressed, and for example, an effect that a load such as a precision part can be safely transported can be obtained. In addition, since the configuration can be simplified, an effect that it can be manufactured at low cost is also obtained.

Embodiment 2. FIG.
FIG. 5 is a view for conceptually explaining the caster dust receiving mechanism shown in FIG. 1 in the caster switching transport cart according to the second embodiment of the present invention, where (a) is a perspective view and (b) is a pinion. The figure explaining the engagement relation of the gear of this, (c) is the perspective view which looked at the engagement slit provided in the gear shaft from the front side. Hereinafter, a description will be given with reference to FIGS. In the figure, the caster dust receiving mechanism 50 is provided at the lower part of the caster board 31a, can be moved horizontally in the left and right directions of the cargo bed indicated by the arrow B1 direction and the arrow B2 direction, and the wheels of the first caster device 12 A plate-shaped dust receiving member 51 (51A, 51B) formed to be divided in two so as to prevent the foreign matter such as dust adhering to 12b from dropping onto the floor surface F, and the dust receiving member 51 are When the wheel 12b of the caster device is in contact with the floor F, it is retracted in the direction opposite to the arrows B1 and B2, the wheel 31b of the second caster device 30 is grounded, and the wheel 12b of the first caster device 12 is grounded. The dust receiving member is moved in the directions of arrows B1 and B2 so as to advance to the lower part of the wheel 12b of the first caster device 12 when the vehicle is lifted from the floor F by a predetermined distance. It has a location 60.

  As shown in FIG. 5 in the second embodiment, the dust receiving member 51 has a central cutout portion 51c in which a central portion of one side portion of a rectangular plate material is cut out in a rectangular shape, and a predetermined corner on the other side portion. A first member 51A having a corner cut portion 51d with the portion cut into a rectangular shape, and disposed on the other side with respect to the first member, and similar to the central cut portion 51c. It consists of a second member 51B having a corner cutout 51d. The first member 51A and the second member 51B are combined so that the corner non-cut portion 51e, which is the remaining portion of the other corner cut portion, enters the one corner cut portion 51d, and the four corners when combined are combined. A dust receiver 52 is provided. The dust receiving part 52 is formed in an area that can sufficiently receive the fall of foreign matters such as dust regardless of the rolling direction of the wheels 12b of the casters. And the dust receiving member 51 is being fixed to the lower part of the caster board 31a by the dust receiving support member 53 so that it can move to arrow B1 and B2 direction smoothly.

  Racks 61 (61A, 61B) are fixed to both edge portions of the portion where the first member 51A and the second member 51B face each other in the front-rear direction of the caster switching transport cart. A gear 62A, which is a pinion meshing with the rack 61A, and a gear 62B, which is a pinion meshing with the rack 61B, are provided on the upper portion of the rack 61 (61A, 61B) with their rotational axes shifted from each other. The sub-gear 621A coaxially fixed to 62A and the sub-gear 621B coaxially fixed to the gear 62B are engaged with each other so that they rotate in opposite directions. The slave gear 621A and the slave gear 621B are provided between the gear 62A and the gear 62B.

  A sprocket (not shown) is provided on the rotating shaft of the gear 62A so as to be adjacent to the left side of the gear 62A, and is engaged with the rotating shaft 21 at a predetermined time by a dust receiving mechanism contact / separation portion 66 described later. A sprocket 64 fixed to a cylindrical gear shaft 63 rotatably provided on the outer peripheral surface of the rotary shaft 21 so as to be driven by the rotary shaft 21 is connected via a chain 65. Note that the rotation shafts of the gears 62A and 62B are pivotally supported with respect to the caster board 31a so as to move up and down together with the dust receiving member 51 and the rack 61 in accordance with the vertical movement of the caster board 31a. On the other hand, since the gear shaft 63 fixing the sprocket 64 is supported by the loading platform 11, the chain 65 is loosened when the second caster device 30 is raised, and becomes tensioned when processed. .

  Here, the slide moving portion of the traversing plate 44 in the lower part of the loading platform 11 is for restricting the movement of the traversing plate 44 in the front-rear direction (left-right direction in the figure) when the second caster device 30 shown in FIG. 1 is used. The transverse plate locking device 80 is provided. As shown in FIG. 4, the transverse plate locking device 80 has a total of two lock insertion ports 44b, one on each of the left and right sides penetrating the upper surface of the transverse plate 44 from a predetermined upper surface portion of the loading platform 11 (not shown in FIG. 4). Further, by inserting the plate 71A shown in FIG. 4B, the horizontal movement of the traversing plate 44 in the figure is restricted.

As shown in FIGS. 4 and 5, the front portion of the rotating shaft 21 is provided with a pin-like engaging member 21 e that penetrates the rotating shaft 21 in the diametrical direction and protrudes from the outer peripheral surface to both sides in the diametrical direction. The joint member 21e is engaged with a notch-shaped engagement slit 631 provided at the left end portion of the gear shaft 63 as shown in FIG. 5C, so that the rotary shaft 21 and the gear shaft 63 are connected. At the time of connection, while rotating the rotary shaft 21 while moving it in the right direction (rear of the carriage), the engaging member 21e and the engaging guide 631a of the engaging slit 631 come into contact with each other to adjust the fitting position. to support.
Further, when releasing the engagement, the rotation shaft 21 is rotated counterclockwise while the engagement member 21e is in contact with the wall surface 631c of the engagement slit 631 by rotating the rotation shaft 21 counterclockwise. Then, the engaging member 21e comes into contact with the wall surface 631b, and the rotating shaft 21 and the gear shaft 63 are separated by pushing the rotating shaft 21 forward of the carriage again. A dust receiving mechanism contacting / separating portion 66 is configured by the pin-shaped engaging member 21e and the engaging slit 631. The gear shaft 63 may be restricted from moving in the axial direction independently of the rotating shaft 21 so that the gear shaft 63 does not move with the rotating shaft 21 even if the rotating shaft 21 moves in the axial direction.
Other configurations are the same as those of the first embodiment.

  Next, the operation of the second embodiment configured as described above will be described. When the wheel 31b of the second caster device 30 is in contact with the floor surface F and the wheel 12b of the first caster device 12 is lifted from the floor surface F, the meshing portion 44a of the traversing plate 44 shown in FIG. When the shaft 65 reaches the left end of the rotationally movable area A of the shaft 21 and the chain 65 becomes in tension as shown in FIG. 5 and the gear shaft 63 is rotated, the chain 65 and the gear 62 meshed with the sprocket 64 and the rack The dust receiving member 51 can be smoothly moved through 61. When connecting the dust receiving mechanism contact / separation part 66 in this state, first, the plate 71A is inserted into the traverse plate lock insertion port 44b from the upper surface of the loading platform 11 and locked to restrict the movement of the traverse plate 44 in the front-rear direction. . Thereafter, the plate 71 that restricts the movement of the rotary shaft 21 to the rear side in the axial direction provided at the rear end of the loading platform is pulled out from the plate fixing guide 72 to release the restriction of the rotary shaft 21 to the rear side in the axial direction. . In this state, when the rotary shaft 21 is rotated clockwise by the handle 22, the handle 22 and the rotary shaft 21 are pulled out to the rear of the loading platform 11, and the screw groove 21 a of the rotary shaft 21 extends from the meshing portion 44 a of the transverse plate 44. It disengages and moves to the idling portion 21b.

As a result, the rotating shaft 21 can move in the rearward direction. Therefore, the engaging member 21e constituting the dust receiving mechanism contacting / separating portion 66 provided on the distal end side of the rotating shaft 21 is cylindrically pulled out rearward. Is engaged with an engagement slit 631 provided at the tip end portion (left end portion in FIG. 5) of the ring-shaped gear shaft 63, mechanically connecting the rotary shaft 21 and the gear shaft 63, and the sprocket 64 is connected to the handle 22. To be rotated by. At this time, the distal end side of the rotating shaft 21 with respect to the locking member 21d passes through an insertion hole (not shown) of the front rotating shaft movement restricting plate 73 and is pivotally supported by the front rotating shaft movement restricting plate 73. The maintained state is maintained.
When the handle 22 is rotated rightward in this state, the rotational power of the sprocket 64 is transmitted to the gear 62A through the chain 65 and also to the gear 62B, and the rotational power of the gear 62A and the gear 62B is transmitted to the dust receiving member 51. (51A, 51B) is transmitted to the racks 61 (61A, 61B), respectively, so that the pair of dust receiving members 51 (51A, 51B) are moved in the horizontal direction as indicated by arrows B1, B2, respectively. The caster dust receiving portion 52 reaches the lower surface of the wheel 12b of the caster device 12, and foreign matter such as dust falling from the wheel 12b of the first caster device 12 can be captured.

On the other hand, in order to store the dust receiving member 51 when traveling outside the dust-proof area from inside the dust-proof area, first, the handle 22 is rotated to the left and the dust receiving member 51 is opposite to the arrow shown in FIG. Move in the direction and evacuate.
Next, in a state where the rotating shaft 21 is rotated counterclockwise by the handle 22 and the engaging member 21e is brought into contact with the wall surface 631c of the engaging slit 631, the rotating shaft 21 is pushed forward and then rotated to the right. The engaging member 21e is brought into contact with 631b and the rotating shaft 21 is pushed forward again to separate the rotating shaft 21 and the gear shaft 63 by the dust receiving mechanism contacting / separating portion 66. Thereafter, the handle 22 is further pushed in the forward direction of the loading platform 11 and the handle 22 is rotated counterclockwise so that the rotationally movable region of the rotating shaft 21 is screwed into the meshing portion 44 a of the traversing plate 44. Next, after the plate 71 is mounted on the plate fixing guide 72 in order to restrict the axial movement of the rotary shaft 21, the plate 71 </ b> A that locks the transverse plate 44 is removed from the lock insertion port 44 b to remove the plate 71. unlock.
Thereafter, by rotating the handle 22 counterclockwise, the caster board 31a is raised, and by raising the caster board 31a to a predetermined position, the wheel 12b of the first caster device 12 is grounded to the floor surface F, and the state of FIG. Thus, the vehicle can travel outside the dust-proof area.

  As described above, according to the second embodiment, the dust receiving member 51 that prevents the foreign matter such as dust adhering to the wheel 12b of the first caster device 12 from dropping on the floor surface F, and the dust receiving member are provided. When the wheel 12b of the first caster device is in contact with the floor surface F, the wheel 31b of the second caster device 30 is grounded, and the wheel 12b of the first caster device floats from the floor surface F. By providing the dust receiving member moving device 60 that moves so as to advance to the lower portion of the wheel of the first caster device in the state of being in the state, it is possible to reliably prevent the dust attached to the vicinity of the wheel from falling. . Therefore, it is possible to prevent the attached dust from falling on the floor surface F such as a clean room. Further, when traveling between inside and outside the dust-proof area having different cleanliness, the transport cart traveling outside the dust-proof area can be directly brought in without changing the transport cart. In addition, since there is no risk of dropping a transported object that is a concern at the time of replacement, an effect can be obtained in terms of both work efficiency and safety.

It should be noted that within the scope of the present invention, a part or all of each embodiment can be freely combined, or each embodiment can be appropriately modified or omitted.
For example, instead of using the rotating shaft 21 provided with the screw groove 21a as a drive member of the lifting device 20, instead of rotating a rod-shaped lever to transmit power to the link mechanism, or using a pantograph type expansion / contraction device, for example, Rotating motion using a chain that can be separated by meshing, which is called a “zip chain”, which consists of two flexible chains engaged by rotation of a chain gear and guide of a zipper roller to form a single hard rod chain May be moved up and down by an actuator that converts linear motion into linear motion. Further, the caster whose rolling direction is freely changed may be only the front wheel. Further, the drive source of the lifting device 20 and the drive source of the dust receiving member moving device 60 may be separated. Further, the dust receiving member moving device 60 is configured using the rack 61 and the pinion gear 62, the sprocket 64 and the chain 65, etc., but is not limited thereto, and is configured by, for example, a lever-like link mechanism. You may do it. The drive source may be an electric system using a rechargeable battery. Further, as the traverse plate locking device, the plate 71A is inserted through the lock insertion port 44b penetrating the upper surface of the traverse plate 44 from the upper surface predetermined portion of the loading platform 11, but the present invention is not limited to this. A lock member such as a pin may be inserted from the side of the frame to interfere with the movement path of the traversing plate 44. It goes without saying that various modifications and changes are possible within the scope of the present invention.

11 loading platform, 12 first caster device, 12a caster shaft, 12b wheel,
13 hand pushing member, 14 stopper, 20 lifting device, 21 rotating shaft (drive member),
21a screw groove, 21b idling part, 21c locking member, 21d locking member,
21e engagement member, 22 handle, 30 second caster device,
31a caster board, 31b wheel, 40 link mechanism,
41 (41A, 41B) connecting member, 42 shaft, 43a, 43b shaft, 44 traversing plate,
44a engaging portion, 44b lock insertion port, 45 rollers,
50 caster dust receiving mechanism, 51 dust receiving member, 51A first member, 51B second member,
51c Central excision part, 51d Corner excision part, 51e Corner non-excision part, 52 Dust receiving part,
53 dust receiving support member, 60 dust receiving member moving device, 61 (61A, 61B) rack,
62 (62A, 62B) gear, 621A slave gear, 621B slave gear, 63 gear shaft,
631 engagement slit, 631a engagement guide, 631b, 631c wall surface,
64 sprocket, 65 chain, 66 dust receiving mechanism contact / separation part,
70 Rotation axis movement restricting part, 71, 71A Plate, 72 Plate fixing guide,
73 Front rotation axis movement restricting plate, 80 transverse plate locking device, A rotation movable region, F floor surface.

Claims (4)

  A first caster device having a predetermined number of wheels provided at a lower portion of the loading platform, and a wheel of the first caster device provided at a lower portion of a caster board disposed at the lower portion of the loading platform so as to be movable up and down. A second caster device having a predetermined number of wheels that can be lowered downward; and a lifting device that lifts and lowers the second caster device relative to the loading platform, wherein the lifting device is rotatable with respect to the loading platform. And a link mechanism that raises or lowers the second caster device according to the rotation direction of the drive member provided between the cargo bed and the second caster device. A caster-switching transport cart characterized by   The link mechanism is crossed in an X shape when viewed from the side, and a pair of rod-like connecting members that are pivotally coupled to each other at the cross portion are symmetrically arranged on one side and the other side of the cargo bed. 2. The caster switching transport cart according to claim 1, wherein a pair of pantograph type expansion and contraction devices are used.   A dust receiving member that is movably provided at a lower portion of the caster board and prevents the foreign matter adhering to the wheels of the first caster device from dropping onto the floor surface, and the dust receiving member is connected to the first caster device. When the wheels are in contact with the floor surface, they are retracted, and when the wheels of the second caster device are grounded and the wheels of the first caster device are floating from the floor surface, the first casters The caster switching transport cart according to claim 1, further comprising a dust receiving member moving device that moves to move to a lower portion of a wheel of the device.   The caster switching transport cart according to claim 3, wherein the dust receiving member moving device uses the driving member as a driving source for moving the dust receiving member.

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