JP4687659B2 - Stacker crane - Google Patents

Description

  The present invention relates to a technique for suppressing a fork bending or a lowering of a tip due to rattling of a guide roller in a slide fork for article transfer attached to a lifting platform of a stacker crane, and vibration during a fork expansion / contraction operation or crane traveling. About.

  Three-dimensional automatic warehouses equipped with a large number of goods storage shelves (rack) that can store various kinds of goods in designated racks and carry goods in and out of these racks fully automatically are used in various fields. Has been. FIG. 9 is an example of a rack apparatus having a large number of racks employed in such a three-dimensional automatic warehouse. One rack 53 is constituted by a pair of front and rear support columns 51 and a pair of shelf receiving members 52 which are mounted so as to protrude from the left and right directions therebetween, and a plurality of racks 53 are connected and arranged in the horizontal and vertical directions. Thus, the rack apparatus 50 having a large number of racks is configured. A plurality of rack devices 50 are usually arranged in parallel at a predetermined interval, and between the rack devices 50, containers storing articles and pallets loaded with articles are fully loaded into and unloaded from the rack 53. The stacker crane 55 travels.

  As shown in FIG. 10, the stacker crane 55 extends along a traveling carriage 57 that travels along a guide rail 56 that is laid vertically along the rack device 50, and a pair of masts 58 that are erected on the traveling carriage 57. There is known one having a lifting platform 59 that moves up and down and a slide fork 60 attached to the lifting platform 59.

  An article W such as a container to be transported is placed on the slide fork 60 and transported. The slide fork 60 is fixed to a lifting platform 59 and is configured to extend and contract in a horizontal front-rear direction (a horizontal direction perpendicular to the traveling direction of the traveling carriage 57). When the article W is carried into the rack 53, the elevator 59 is first moved to the front of the designated rack 53. Next, the slide fork 60 on which the article W is placed is extended into the rack 53, and the lifting platform 59 is slightly lowered in this state. By this operation, the article W is moved onto the shelf receiving member 52 in the rack 53. When unloading from the rack 53, the reverse operation is performed.

  However, the transfer of the article W using the slide fork 60 has the following problems. That is, in order to increase the storage rate of the articles W in the rack device 50, it is desirable that the vertical interval of the shelf receiving members 52 be as narrow as possible. However, when the slide fork 60 is extended into the rack 53, the slide fork 60 is cantilevered by the lifting platform 59 as shown in FIG. For this reason, the slide fork 60 is bent by the load of the article W placed on the tip. As a result, the end of the extended slide fork 60 is lowered from the original horizontal position.

If there is bending due to such a load, it is necessary to determine the vertical distance of the shelf receiving member 52 with a margin as much as the maximum amount of tip descending due to the bending. If there is a margin, there arises a problem that the storage rate decreases by the margin. In addition, when the slide fork 60 is extended and contracted, there is a problem that the entire lifting platform 59 and the stacker crane 60 vibrate. As a prior art for solving such a problem, for example, there is a technique disclosed in Patent Document 1. However, in the case of this technique, even if the deflection due to the load of the article can be compensated, the effect of reducing the vibration during expansion and contraction of the slide fork cannot be expected.
Japanese Patent Laid-Open No. 06-199406

  The present invention has been made to solve these problems of the prior art, and the problem is that the fork in the slide fork for transferring articles attached to the lifting platform of the stacker crane is elongated by the guide roller rattling or the like. It is an object of the present invention to provide a technique for suppressing the lowering of the front end and vibration at the time of fork telescopic operation or crane traveling.

The invention according to claim 1 for solving the above-described problem is a traveling cart that travels along a rail, a pair of masts that are erected in the traveling direction on the traveling cart, and along the pair of masts. A stacker crane comprising a lifting platform that moves up and down, and a slide fork that is attached to the lifting platform and expands and contracts in a horizontal direction perpendicular to the traveling direction. The lifting platform includes upper and lower left and right portions along the traveling direction. Each guide roller has a pair of guide rollers that roll while sandwiching the mast from a direction perpendicular to the traveling direction, and each guide roller has a guide shaft having two parallel surfaces perpendicular to the support shaft. A guide roller that is inserted into and supported by two holes provided on two opposing surfaces of the member, and that is disposed on the opposite side of the extension side of the slide fork among a pair of guide rollers disposed on the upper left and right sides Support There holes to be inserted is movable parallel to the stretching direction of the slide fork the support shaft is formed in a long hole, the air spring mounted between the outer wall inner surface of the guide member the support shaft is opposite to it The stacker crane is biased toward the extension side of the slide fork, and the biasing force can be varied by changing the internal pressure of the air spring .

According to such a configuration, when an article is placed on the slide fork and extended , the internal pressure of the air spring is increased, thereby increasing the urging force to the support shaft of the guide roller disposed on the side opposite to the extended side. be able to. When the urging force increases, the support shaft moves in the extending direction of the slide fork, the rolling surface of the guide roller comes into contact with the mast, and the mast is pushed. Then, by the reaction force, the upper part of the lifting platform is tilted to the opposite side, and the distal end portion of the extended slide fork is lifted. As a result, the bending of the slide fork due to the load of the article and the lowering of the slide fork tip from the horizontal position due to the gap between the rolling surface of the guide roller holding the mast and the mast are corrected. Further, when the slide fork carrying the load is expanded and contracted, the urging force can be increased by increasing the internal pressure of the air spring, and the mast can be held with a strong force by the pair of guide rollers at the upper part of the lifting platform. By virtue of such clamping, vibration during expansion and contraction of the slide fork can be reduced.

The invention according to claim 2 is characterized in that, in the stacker crane according to claim 1, the internal pressure of the air spring is increased in a state where an article is placed and the slide fork is extended. It is a stacker crane.

By controlling the internal pressure of the air spring in this way, the upper part of the lifting platform can be slightly tilted to the opposite side, and the distal end portion of the extended slide fork can be lifted. Therefore, it is possible to correct the bending of the slide fork due to the load of the article and the lowering of the slide fork tip from the horizontal position due to the gap between the rolling surface of the guide roller holding the mast and the mast.

According to a third aspect of the present invention, in the stacker crane according to the first or second aspect, the internal pressure of the air spring is increased when the traveling carriage is traveling.

If the internal pressure of the air spring is controlled in this way, the pair of guide rollers at the upper part of the elevator platform sandwiches the mast with a strong force. Therefore, there is an effect of reducing the vibration of the elevator during traveling.

  Hereinafter, an embodiment of a stacker crane according to the present invention will be described with reference to the drawings. FIG. 1 is a front view of the stacker crane 1 and FIG. 2 is a side view. The stacker crane 1 according to the present invention is characterized by an attachment mechanism of an elevating guide roller 3 attached to an elevating platform 2. Other parts are the same as those of the conventional stacker crane 55 shown in FIG. Therefore, the front view of FIG. 1 and the side view of FIG. 2 are substantially the same as FIGS. 10 and 11 described in the section “Background Art”.

  The stacker crane 1 includes a traveling carriage 5, a pair of masts 6, and a lifting platform 2 as main parts. The traveling carriage 5 travels on the traveling rail 8 laid along the front width direction of the rack device 50 as shown in FIG. 9 by the wheels 10 driven by the traveling motor 9, and the entire stacker crane 1 is illustrated. Move left and right. On the traveling carriage 5, a pair of masts 6 are erected separately from the front part and the rear part in the traveling direction. The upper part is connected by the upper frame 12. A plurality of horizontally rotating guide rollers are mounted in the upper frame 12, and these guide rollers are squeezed and rolled on the upper guide rail 13 to prevent overturning.

  Between the pair of masts 6 is mounted a lifting platform 2 that is lifted and lowered by a lifting wire 14. The lifting wire 14 is wound around a winding drum 17 provided on one mast 6 via a driven pulley 16 attached to the upper frame 12. The winding drum 17 is driven forward and backward by an elevator motor 18 that is controlled by an inverter, winds and unwinds the lifting wire 14, and lifts the lifting platform 2. The height position of the lifting platform 2 is detected by counting signals from an encoder attached to the winding drum 17.

  A slide fork 20 for transferring the article W to and from the rack 53 of the rack device 50 is attached to the lift 2. As shown in FIG. 2, the slide fork 20 is configured to extend and contract in a horizontal front-rear direction (a horizontal direction perpendicular to the traveling direction of the traveling carriage 5). When carrying the article W into the rack 53, first, the elevator 2 is moved to the front of the designated rack 53. Next, the slide fork 20 on which the article W is placed is extended into the rack 53, and the lifting platform 2 is slightly lowered in this state. By this operation, the article W is moved onto the shelf receiving member 52 in the rack 53. When the article W is unloaded from the rack 53, the reverse operation is performed. At the time of conveyance, the article W is carried on the slide fork 20.

  As shown in FIG. 3, the lifting platform 2 includes a lifting base 22 that supports the slide fork 20, and guide members 23 that are erected and attached to both ends in the left-right direction (the traveling direction of the traveling carriage 5). Yes. A pair of guide rollers 3 is attached to the upper and lower portions on the outer surface side of each of the left and right guide members 23. Each pair of guide rollers 3 is mounted so as to roll while sandwiching the mast 6 from a direction (front-rear direction) perpendicular to the traveling direction of the traveling carriage 5. The pair of guide rollers 3 on the upper and lower sides sandwich the mast 6 so that the elevating base 22 is kept horizontal and moves up and down without swinging in the front-rear direction.

  The mast 6 is composed of a square pipe, and the width dimension in the front-rear direction has an error due to processing accuracy. Therefore, the gap between each pair of guide rollers 3 that rolls while holding the mast 6 in the front-rear direction is widened by a slight margin considering the dimensional error. That is, a slight gap exists between the rolling surface of the guide roller 3 and the square pipe surface of the mast 6. Such a lifting platform 2 is lifted and lowered by being suspended by the lifting wire 14 as described above.

  Next, consider a case where an article W such as a container is placed on the slide fork 20 under such a configuration and extended to the rack device side (front side). The center of gravity of the lifting platform 2 moves forward by the extension of the slide fork 20 and the movement of the article W thereby. Therefore, a rotating moment in the direction of the arrow 26 in FIG. Due to this rotational moment, the rolling surface of the upper rear guide roller 3UB comes into contact with the surface of the mast 6, and the gap becomes zero. The mast 6 receives a backward reaction force indicated by an arrow 27. A gap corresponding to the above-described margin is generated between the rolling surface of the upper front guide roller 3UF and the surface of the mast 6. With respect to the lower guide roller 3, the rolling surface of the lower front guide roller 3 LF contacts the surface of the mast 6 so that the gap becomes zero, and the mast 6 receives a forward reaction force indicated by an arrow 28. A gap is generated between the rolling surface of the lower rear guide roller 3LB and the surface of the mast 6 by the above-described margin.

  Since the gaps between the rolling surfaces of the four guide rollers 3UB, 3UF, 3LB, and 3LF and the surface of the mast 6 change in this way, the lifting platform 2 rotates slightly forward and forward. As a result, the elevating base 22 is slightly inclined forward and downward. When the elevating base 22 is tilted in this way, the tip of the extended slide fork 20 is lowered from the original horizontal position. The downward movement due to the bending of the slide fork 20 is further added to the downward movement due to such an inclination, and the tip of the slide fork 20 is further lowered from the original horizontal position.

  The stacker crane 1 of the present embodiment is devised for the attachment mechanism of each pair of guide rollers 3 disposed on the upper left and right sides of the lifting platform 2 in order to correct the lowering of the tip of the slide fork 20. Next, the attachment mechanism will be described. FIG. 5 is a cross-sectional view of the left guide member 23L as viewed from the section line AA in FIG. As shown in the drawing, an upper rear guide roller 3UB and an upper front guide roller 3UF are attached to the upper part of the left guide member 23L so as to roll while sandwiching the left mast 6L in the front-rear direction. Guide rollers 3UB and 3UF are rollers with built-in bearings, and are made of, for example, urethane resin.

  The guide roller 3UF attached to the front side (the extension side of the slide fork 20) is rotatably supported by a horizontal support shaft 30F. The support shaft 30F is fixed to the outer wall 32 of the left guide member 23L. On the other hand, a horizontal support shaft 30B that rotatably supports the guide roller 3UB attached to the rear side is fixed to a slide block 33B that is attached to the left guide member 23L so as to be slidable back and forth. FIG. 6 is a side view of the left guide member 23L along the line BB in FIG. As shown in FIG. 6, an elongated hole 34B for allowing the support shaft 30B to move horizontally in the front-rear direction is formed in a portion where the support shaft 30B penetrates the outer wall 32 of the left guide member 23L. That is, the rear guide roller 3UB is attached to the support shaft 30B and the sliding block 33B so as to move back and forth by a slight distance with respect to the left guide member 23L.

  An air spring 35B is attached as an actuator for moving the rear guide roller 3UB back and forth as described above. The air spring 35B is attached in a state of being sandwiched between the rear surface of the sliding block 33B and the inner surface of the rear outer wall 32B of the left guide member 23L. The air spring 35B is a spring device using the elastic force of compressed air, and has the property that when the internal air pressure or the amount of internal air changes, the spring constant changes and the elastic force (load bearing force) changes even if the amount of displacement is the same.

  Next, the operation of the air spring 35B attached in this way will be described. Note that the left and right guide members 23 are configured symmetrically, and the internal pressures of the left and right air springs 35B are the same. Therefore, the left guide member 23L will be described as an example. When the internal pressure of the air spring 35B is increased in the attached state as shown in FIG. 5, the spring constant increases and the elastic force increases, and the sliding block 33B is pushed forward. Then, the rear guide roller 3UB moves to the front side by the gap between the rolling surface and the mast 6, and the rolling surface comes into contact with the left guide member 23L. When the internal pressure of the air spring 35B is further increased, the rear guide roller 3UB strongly presses against the left mast 6L. If the sliding surface of the rear guide roller 3UB does not move forward in contact with the left guide member 23L, a reaction force equal to the pressing force acts on the rear outer wall 32B of the left guide member 23L that supports the air spring 35B.

  When the rear guide roller 3UB pushes the left mast 6L, a rotational moment in the direction opposite to the arrow 26 in FIG. 4 acts on the left guide member 23L. When the opposite rotational moment value becomes larger than the rotational moment indicated by the arrow 26 in FIG. 4 acting on the left guide member 23L, the rear guide roller 3UB further starts to move forward. When the front movement starts, the left guide member 23L is tilted to the left (the upper part is the rear side). When the upper portions of the left and right guide members 23 are both inclined rearward, the lifting base 22 supported thereby lifts the front side (the extension side of the slide fork 20). As a result, the extension end of the slide fork 20 is also lifted. When the rear guide roller 3UB continues to move further forward, the rolling surface of the front guide roller 3UF comes into contact with the mast 6L and the tilting operation stops.

  When the article W is not placed on the extended slide fork 20, the value of the rotational moment in the direction indicated by the arrow 26 in FIG. 4 is relatively small. In that case, the extension end of the slide fork 20 is lifted only by generating a small driving force in the air spring 35B. On the other hand, when the article W is placed, the extended end of the slide fork 20 cannot be lifted unless a large driving force is generated in the air spring 35B. In the stacker crane 1 of this embodiment, such a large driving force is generated by sufficiently increasing the internal pressure of the air spring 35B. As a result, the above-described gap between the rolling surface of each guide roller 3 and the surface of the mast 6, the elastic deformation of the guide roller 3, the bending of the slide fork 20, and the like are corrected. I have to.

  Note that the movable distance of the upper part of the left guide member 23L is the gap distance that is the difference between the distance between the rolling surfaces of the upper left and right guide rollers 3UB and 3UF and the front and rear width of the mast 6 when the internal pressure of the air spring 35B is zero. Further, a value obtained by adding a radius change due to elastic deformation of the guide rollers 3UB and 3UF. The value is a small value of about several mm. Since the movable distance is such a small value, the lift base 22 is slightly inclined, but the lifted end of the extended slide fork 20 is increased. Therefore, the amount of decrease due to bending or the like can be sufficiently corrected. The elongated hole 34B is formed so that the rear guide roller 3UB can move back and forth by about several mm.

  FIG. 7 is an example of a pneumatic circuit that switches the internal pressure of the air spring 35 attached to the left and right guide members 23. The internal pressure of the air spring 35B is zero when the solenoid of the solenoid valve 37 is not excited, and becomes a constant value controlled by the pressure controller 40 when excited. The hydraulic pump 38, the auxiliary tank 39, and the like are attached to the lower side of the elevating base 22.

  When the article W is delivered between the lifting platform 2 provided with the air spring 35 acting as described above and the rack device 50, the operation is performed as follows. When the article W on the lifting platform 2 is moved to the rack device 50, the slide fork 20 is extended with the internal pressure of the air spring 35B being high. Then, with the article W in the rack 53, the internal pressure of the air spring 35 </ b> B is reduced to zero, and the elevator 2 is slightly lowered to deposit the article W in the rack 53. On the contrary, when the article W is received from the rack device 50, the slide fork 20 is extended with the internal pressure of the air spring 35B being zero, the elevator 2 is slightly lifted to receive the article W on the slide fork 20, In this state, the internal pressure of the air spring 35B is increased, the slide fork 20 is moved back as it is, and the article W is moved to the center position of the lifting platform 2.

  By operating in this way, it is possible to correct the drop of the tip of the slide fork 20 when the article W is on the extended slide fork 20. Further, in the conventional apparatus, when the slide fork 20 on which the article W is loaded extends and retracts, vibration is easily generated in the lifting platform 2, but in this embodiment, the left and right upper rear guide rollers 3UB are masted by the air spring 35B. 6 is effective in reducing vibration. Further, when the stacker crane 1 is driven, the inner pressure of the air spring 35B is increased so that the mast 6 is held by the pair of upper guide rollers 3. By doing in this way, the vibration of the lifting platform 2 during traveling can also be reduced.

(Modified embodiment)
FIG. 8 is a modified embodiment of how to attach the pair of guide rollers 3UB and 3UF arranged on the upper part of the left guide member 23L shown in FIG. In this embodiment, the upper front guide roller 3UF is also supported by the air spring 35F so as to be movable back and forth in the same manner as the upper rear guide roller 3UB. This is an embodiment corresponding to a case in which a slide fork 20 that can be extended in both the front and rear directions is employed. The method for controlling the internal pressure of the air spring 35 is the same as in the above-described embodiment. The internal pressure of the air spring 35 on the side where the slide fork 20 extends is zero, and only the internal pressure of the air spring 35 on the opposite side is increased. By doing so, it is possible to correct the lowering of the tip during extension when the slide fork 20 is extended to either side.

  When the stacker crane 1 is driven, the inner pressure of both air springs 35 is increased and the mast 6 is held between the pair of upper guide rollers 3. By doing so, the vibration of the lifting platform 2 during traveling can also be reduced.

  Further, in the description of the embodiments so far, the example in which the air spring is used as the elastic member that can change the elastic coefficient has been described. Instead, a hydraulic damper that changes the elastic coefficient by controlling the hydraulic pressure and the oil amount is used. May be used. Moreover, you may make it change the load which responds with respect to the load added using the servomotor.

It is a front view of the stacker crane 1 concerning one embodiment of the present invention. It is a side view of the stacker crane 1 shown in FIG. It is a perspective view of the raising / lowering stand 2 of the stacker crane 1. FIG. It is a left side surface of the lifting platform 2. It is sectional drawing of the left guide member 23L seen from cut surface line AA in FIG. FIG. 6 is a side view of a left guide member 23L along the line BB in FIG. 5. 2 is an example of a pneumatic circuit that switches an internal pressure of an air spring 35. FIG. 6 is a modified embodiment of FIG. It is an example of the rack apparatus employ | adopted as a three-dimensional automatic warehouse. FIG. 2 is a view corresponding to FIG. FIG. 3 is a diagram corresponding to FIG.

Explanation of symbols

  In the drawings, 1 is a stacker crane, 2 is a lifting platform, 3 is a guide roller, 5 is a traveling carriage, 6 is a mast, 8 is a traveling rail, 13 is an upper guide rail, 20 is a slide fork, 23 is a guide member, 30B, Reference numeral 30F denotes a support shaft, and 35 denotes an air spring.

Claims (3)

A traveling carriage that travels along the rail, a pair of masts that are arranged upright in the traveling direction on the traveling carriage, an elevator that moves up and down along the pair of masts, and the traveling direction that is attached to the elevator A stacker crane equipped with a slide fork that expands and contracts in a horizontal direction perpendicular to
The lifting platform includes a pair of guide rollers that roll while sandwiching the mast from a direction perpendicular to the traveling direction at upper and lower left and right sides along the traveling direction,
Each guide roller is supported by being inserted into two holes provided in two opposing surfaces of a guide member having two parallel surfaces perpendicular to the support shaft, the support shaft inserted through the center of rotation of the guide roller.
Of the pair of guide rollers disposed on the left and right upper portions, a hole through which the support shaft of the guide roller disposed on the side opposite to the extending side of the slide fork is formed as an elongated hole. Can be translated in the direction of expansion and contraction of the slide fork,
The support shaft is urged toward the extending side of the slide fork by an air spring attached between the guide member and the inner surface of the outer wall facing the guide shaft, and the urging force can be varied by changing the internal pressure of the air spring. A stacker crane characterized by the above. The stacker crane according to claim 1, wherein an internal pressure of the air spring is increased in a state where an article is placed and the slide fork is extended. 3. The stacker crane according to claim 1, wherein an internal pressure of the air spring is increased when the traveling carriage travels. 4.