Transport device

Abstract

The present invention provides an elevated transfer device that can tilt and transport items appropriately without relying on lifting distance. In the elevated transfer type transport device (elevated transfer vehicle) 1 of the present invention, the lifting device 8 includes: first and second transmission belt members 12 and 14 of the suspension and holding device 10, and a drive device including lifting rollers 26 and 30 and drive shaft 34 for winding and unwinding the transmission belt members; the holding device 10 and the trolley body 2 have abutting members / abutted members 44 and 46 that abut against each other at the reference rising position; the first transmission belt member 12 is suspended from the holding device 10 at the first position A, the second transmission belt member 14 is suspended from the holding device 10 at the second position B, and is provided with a spring 52; the spring 52 allows the holding device 10 to tilt α1 and α2 with the abutting parts 46a and 44a of the abutting member 46 and the abutted member 44 as fulcrum when the first and second transmission belt members 12 and 14 are wound to the same length at the reference rising position.

Description

Transfer device The present invention relates to a transfer device, and more particularly to an overhead transfer device that travels on an overhead track and transfers articles. In Patent Document 1, an overhead transfer device that tilts and transfers a cassette is disclosed. The overhead transfer device holds the cassette with grippers mounted at the front ends of two conveyor belts, and winds the respective conveyor belts using rollers of different diameters, whereby the winding amounts of the two conveyor belts are made different from each other. Thereby, the grippers in the horizontal posture at the lower limit position gradually tilt as they rise, and become the target tilt posture at the upper limit position. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 8-188375 (Problems to be Solved by the Invention) However, in the overhead transfer device of Patent Document 1 described above, in order to tilt the cassette at a target fixed tilt angle, it is necessary to adjust the length of the conveyor belt or the roller diameter according to the lifting distance (that is, the distance between the lower limit position and the upper limit position of the cassette). Therefore, in order to obtain the optimum tilt angle of the cassette, it is necessary to adjust the length of the conveyor belt or the roller diameter according to the specifications such as the height to the overhead track or the loading port for each object where such a transfer device is installed, and thus there is a problem that the corresponding adjustment becomes complicated and the cost increases. Therefore, the present invention has been completed to solve the above problems, and an object thereof is to provide an overhead transfer device that can tilt and transfer an article appropriately without depending on the lifting distance. (Technical Means for Solving the Problem) To achieve the above object, the present invention is an overhead transfer device that travels on an overhead track and transfers an article, characterized in that it includes: a carriage main body portion, a holding device for holding an article, and a lifting device for lifting the holding device relative to the carriage main body portion; the lifting device includes: a first suspension member and a second suspension member for suspending the holding device, and a driving device for winding and unwinding the first suspension member and the second suspension member; the holding device includes: an abutting member that abuts against the carriage main body portion at a predetermined rising position where the holding device rises relative to the carriage main body portion; the carriage main body portion includes an abutted member against which the abutting member of the holding device abuts; the first suspension member suspends the holding device at a first position of the holding device, and the second suspension member suspends the holding device at a second position of the holding device; the driving device winds or unwinds the first suspension member and the second suspension member by the same length; it further includes: a tolerance portion; when the abutting member of the holding device abuts against the abutted member of the carriage main body portion at a predetermined rising position and the first suspension member and the second suspension member are wound by the same length, the tolerance portion allows the holding device to tilt with the abutting portion between the abutting member and the abutted member as a fulcrum. According to the invention of this configuration, since it is provided with a lifting device that winds up the first suspension member and the second suspension member by the same length, and when the first suspension member and the second suspension member are wound up by the same length at a predetermined rising position where the abutting member of the holding device abuts against the abutting member of the carriage main body, there is a permitting portion that permits the inclination of the holding device with the abutting portion between the abutting member and the abutting member as a fulcrum, thus, regardless of the lifting distance (the winding amount of the suspension member), it can achieve a fixed inclination angle required for the inclination of the holding device. Also, in the present invention, preferably, when the abutting member of the holding device is observed from the horizontal direction, it is disposed between a first position and a second position; the permitting portion is such that when the first suspension member and the second suspension member are wound up by the same length at a predetermined rising position, with the abutting portion between the abutting member and the abutting member as a fulcrum, the first position is displaced upward and the second position is displaced downward to permit the inclination of the holding device. According to the invention of this configuration, it can more effectively achieve the fixed inclination angle required for the inclination of the holding device. Also, in the present invention, preferably, the permitting portion is provided with an elastic member, and when the first suspension member and the second suspension member are wound up by the same length at a predetermined rising position, by elastic deformation, it permits the inclination of the holding device with the abutting portion between the abutting member and the abutting member as a fulcrum. According to the invention of this configuration, it can more effectively permit the inclination of the holding device. Also, in the present invention, preferably, in a state where the holding device does not hold an article, the elastic member is contracted relative to its natural length. According to the invention of this configuration, the elastic member is contracted relative to its natural length, and accordingly, the resulting boosting pressure is imparted to the holding device, whereby when the holding device holding an article (for example, from a loading port) is lifted, it can suppress the inclination of the holding device. Also, in the present invention, preferably, the abutting member of the holding device and the abutting member of the carriage main body define the horizontal position and the rising position of the holding device at a predetermined rising position. According to the invention of this configuration, the abutting member of the holding device and the abutting member of the carriage main body, in addition to serving as a fulcrum when the holding device inclines, also serve to position the holding device when it rises. Also, in the present invention, preferably, at the first position of the holding device, a first connecting member for connecting the first suspension member to the base member of the holding device is provided; at the second position of the holding device, a second connecting member for connecting the second suspension member to the base member of the holding device is provided; the first connecting member is fixed to the base member; the second connecting member is mounted on the base member so as to be relatively displaceable in the vertical direction with respect to the base member; the tolerance portion includes an elastic member provided between the base member and the second connecting member and allowing relative displacement between the base member and the second connecting member. According to the present invention having such a configuration, the elastic member is bent by the force from the base member of the holding device and the second connecting member connected to the second suspension member, whereby it can effectively allow the inclination of the holding device. Also, in the present invention, preferably, the abutting member is a pin member protruding upward; the abutted member is a guiding member that is open downward and receives and supports the pin member. According to the present invention having such a configuration, it can more effectively set the inclination angle of the fixing required for inclining the holding device. (Effect compared with the prior art) According to the present invention, it can appropriately incline and convey an article regardless of the lifting distance. Next, with reference to the accompanying drawings, an overhead traveling type conveying device according to an embodiment of the present invention will be described. First, with reference to FIG. 1, the overall configuration of the overhead traveling type conveying device (overhead carrier) according to an embodiment of the present invention will be described. FIG. 1 is a side view showing a schematic configuration of the entire overhead traveling type conveying device according to an embodiment of the present invention. Further, in the present embodiment described below, the present invention is applied to a conveying device that accommodates and conveys semiconductor wafers in a clean room of a semiconductor manufacturing factory. First, as shown in FIG. 1, reference numeral 1 denotes the overhead traveling type conveying device (overhead carrier) of the present embodiment (hereinafter referred to as the "conveying device"). The conveying device 1 includes a conveyance cart body (hereinafter referred to as the "cart body") 2. The cart body 2 is suspended from a track guide 4 installed on the ceiling in a building such as a clean room, and is moved by a traveling mechanism 6 that operates with respect to the track guide 4, and can be moved to a target position. Further, in the following description and each drawing, the so-called "front" and "rear" refer to the front and rear of the conveying device 1 observed from a direction orthogonal to the traveling direction of the conveying device 1 and in the horizontal direction; the so-called "side" refers to the side with respect to the front and rear of the conveying device 1. Also, the so-called "front" refers to the front of the conveying device 1 observed from the direction of the surface where the open cassette 18 forms the opening 24. Next, the transfer device 1 includes a lifting device (elevator) 8 and a holding device (hand unit having a tilting mechanism) 10. The lifting device 8 is a device that lifts the holding device 10 by means of lifting drive belts 12 and 14 that function as so-called cranes, and is located below the traveling mechanism 6 and is mounted on the carriage body 2. The holding device 10 is used to hold (retain) the open cassette 18 placed on the loading port 16 of the semiconductor manufacturing device provided in the building by means of the chuck 20 and is configured to be able to transfer the wafers (transfer objects) 22 in the open cassette 18. The open cassette 18 has an opening 24 formed on one surface of its front side, and the wafers 22 on the loading port 16 are horizontally transferred into the open cassette 18 from the opening 24 (the wafers 22 can be taken out and put in). Furthermore, for ease of understanding, in the diagrams including the side view of FIG. 1, although the state in which the wafers 22 protrude from the opening 24 of the open cassette 18 is illustrated, in reality, the wafers 22 are entirely accommodated in the open cassette 18. Here, the open cassette 18 is not provided with a structure for holding the position of the wafers 22. During transfer, although generally no large force in the horizontal direction is applied, and thus the wafers 22 do not move even if a configuration such as closing the opening 24 is not formed, when traveling, there is a possibility that the wafers 22 may move due to centrifugal force in a bend or traveling vibration, etc. Therefore, in the present embodiment, as described below, when traveling at high altitude, the holding device 10 is tilted to effectively transfer the wafers 22. Next, the basic structure of the lifting device 8 will be described with reference to FIGS. 1 to 3. FIG. 2 is a left side view of the schematic configuration of the lifting device of the transfer device showing an embodiment of the present invention observed from the left side, and FIG. 3 is a top view of the schematic configuration of the lifting device of the transfer device showing an embodiment of the present invention observed from above. As shown in FIGS. 1 to 3, the lifting device 8 includes a first lifting drive belt (first suspension member) 12 composed of a pair of drive belts, a pair of lifting rollers 26, and a pair of idler wheels 28. The starting end of the first lifting drive belt 12 is mounted on the lifting roller 26, and by rotationally driving the lifting roller 26 and via the idler wheels 28, the first lifting drive belt 12 is wound up or released. Also, the lifting device 8 includes a second lifting drive belt (second suspension member) 14 composed of a single drive belt, a lifting roller 30 for the second lifting drive belt, and two idler wheels 32. The starting end of the second lifting drive belt 14 is mounted on the lifting roller 30, and by rotationally driving the lifting roller 30 and via the two idler wheels 32, the second lifting drive belt 14 can be wound up or released. Here, a total of three lifting rollers 26 and 30 are driven by a common drive shaft 34 connected to a motor (not shown), so that they are all driven at the same rotational speed and the same amount of rotation. Also, the three lifting rollers 26 and 30 all have the same diameter. Therefore, in this embodiment, with this configuration, when the lifting rollers 26 and 30 rotate, the first lifting belt 12 and the second lifting belt 14 are wound up or released by the same length. Next, as shown in FIG. 1, the lower end of the first lifting belt 12 is mounted on the holding device 10 at the first position A on the opening 24 side (front side) via the first connecting member (first connecting bracket) 36, and the lower end of the second lifting belt 14 is mounted on the holding device 10 at the second position B on the back side via the second connecting member (second connecting bracket) 40. That is, the first lifting belt 12 suspends the holding device 10 at the first position A on the opening 24 side of the open cassette 18 of the holding device 10, and the second lifting belt suspends the holding device 10 at the second position B on the back side of the holding device 10. Also, in this embodiment, a pair of positioning guide members (hereinafter referred to as "guide members") 44 opening downward are installed on the lifting device 8 of the cart body 2. As shown in FIG. 3, the pair of guide members 44 are respectively arranged at the left and right edge portions of the lifting device 8, and as described below, they come into contact with a pair of positioning pin members (hereinafter referred to as "pin members") 46 provided on the holding device 10. More specifically, concave portions (contact portions) 44a having a semi-circular cross-section are respectively formed on the pair of guide members 44, and the cylindrical portions (contact portions) 46a of the pair of pin members 46 having semi-circular outer surfaces respectively come into contact with the concave portions 44a. Next, the basic structure of the holding device 10 will be described with reference to FIGS. 4 to 6. FIG. 4 is a front view of the device showing the schematic configuration of the holding device according to the embodiment of the present invention, FIG. 5 is a left side view of the device showing the schematic configuration of the holding device according to the embodiment of the present invention, and FIG. 6 is a rear view of the device showing the schematic configuration of the holding device according to the embodiment of the present invention. First, as shown in FIGS. 4 to 6, the holding device 10 has a bottom plate 50 on which various components are installed. Furthermore, in FIGS. 4 to 6, the open cassette 18 is held by the chuck 20 provided on the holding device 10. On the bottom plate 50, at its first position A (symbol A is marked in the side views of FIGS. 1 and 5), a pair of first lifting belts 12 are installed via a pair of first connecting members 36. The first connecting members 36 are constituted by, for example, U-shaped brackets that are open upward. Further, although the first position A where the first lifting belts 12 are installed is a pair of two positions in the front view (FIG. 4) and the rear view (FIG. 6), it can be regarded as one position in the side view (FIGS. 1 and 5). In the present embodiment, the following description is made on the premise that the first position A refers to the one first position A observed in the side view. Further, although the description of the detailed installation structure is omitted, at the first position A, the first connecting members 36 are fixed to the bottom plate 50 so that the first connecting members 36 and the first lifting belts 12 do not relatively displace in the vertical direction with respect to the bottom plate 50. Also, on the bottom plate 50, at its second position B (symbol B is shown in the side views of FIGS. 1 and 5), a second lifting belt 14 is installed via a second connecting member 40. Further, although the description of the detailed installation structure is omitted, at the second position B, the second connecting member 40 is installed relative to the bottom plate 50 so as to be relatively displaceable in the vertical direction. Thereby, as described below, when the bottom plate 50 is tilted, the bottom plate 50 can relatively displace with respect to the second connecting member 40 and the second lifting belt 14. Here, in FIGS. 4 to 6, reference numeral 12a is the lower end portion of the first lifting belt 12, which serves as the mounting portion toward the first connecting member 36. Also, reference numeral 36a is a fixing member for mounting its lower end portion 12a to the first connecting member 36. Also, reference numeral 14a is the lower end portion of the second lifting belt 14, which serves as the mounting portion toward the second connecting member 40. Also, reference numeral 40a is a fixing member for mounting its lower end portion 14a to the second connecting member 40. Next, at the second position B, a compression spring 52 is installed between the lower end portion (the bottom part of the U-shaped bracket) of the second connecting member 40 and the lower surface portion of the bottom plate 50. In the present embodiment, the compression spring 52 mainly has two functions. First, the compression spring 52 is assembled between the second connecting member 40 and the bottom plate 50 in a state where it is compressed by a predetermined amount. Thereby, it has the following function: it can generate a "pressure increase" of a predetermined amount, and by this pressure increase, when the holding device 10 lifts the open cassette 18 on the loading port 16, it can counteract the weight and suppress the inclination of the holding device 10 and the open cassette 18. The second connecting member 40 is configured such that, due to the pressure increase generated by the compression spring 52, it can be restricted from displacing downward from a predetermined position. Second, as described with reference to FIGS. 7 to 10, after the pin member 46 abuts against the guide member 44, when the first lifting belt 12 and the second lifting belt 14 are further wound up, the second connecting member 40 is displaced relative to the bottom plate 50, and the compression spring 52 is compressed (tightened). This allows the bottom plate 50 to tilt, and further allows the holding device 10 to tilt. In other words, the conveying device 1 of the present embodiment mainly includes the bottom plate 50, the second connecting member 40 that can be displaced relative to the bottom plate 50 in the vertical direction, and the compression spring 52 to form a tilting allowance portion that allows the holding device 10 to tilt. Further, the compression spring 52, as an elastic material that can exhibit the functions described above, may be rubber, for example. Next, as shown in FIGS. 4 to 6, a pair of pin members 46 extending upward are installed at the left and right edge portions of the holding device 10. At the upper ends of these pair of pin members 46, a cylindrical portion (abutting portion) 46a having a semi-circular outer surface with the same size and shape as the concave portion 44a of the above-mentioned guide member 44 is formed. As shown in FIG. 5, these pair of pin members 46 are arranged such that when viewed from the side and observed from the horizontal direction, they are located between the first position A suspended by the first lifting belt 12 and the second position B suspended by the second lifting belt 14. A pair of guide members 44 of the lifting device 8 are also respectively provided directly above the pair of pin members 46 positioned as such. Furthermore, as a modification, a member having the same function as the pin member 46 may be provided on the side of the cart body 2 (for example, the lifting device 8), and on the other hand, a member having the same function as the guide member 44 may be provided on the side of the holding device 10. Further, for example, in this modification, based on the technique of mutual abutment, the guide member 44 or a member having the same function may be regarded as an "abutting member", and the pin member 46 or a member having the same function may be regarded as a "member to be abutted". In this modification, it can also function as a "fulcrum" described below, and the holding device 10 can be tilted. Also, as a modification, for example, in the side view as shown in FIG. 5, the pin member 46 may be arranged at a position overlapping the second position B. Also, as a modification, the pin member 46 may be arranged on the outer side of the second position B. When viewed from the side and observed from the horizontal direction, they are arranged in the order of the first position A, the second position B, and the pin member 46. In such modifications, it can also function as a "fulcrum" described below, and the holding device 10 can be tilted. Further, in the present embodiment, although the pin member 46 and the guide member 44 are attached to the respective devices 8 and 10, as a modification, a contact portion or a contacted portion having the same function as the pin member 46 or the guide member 44 may be integrally formed on the carriage body 2, the lifting device 8, or the holding device 10. Further, as a modification, the pin member 46 and the guide member 44 may not be a pair but may be single members respectively. Furthermore, by making them a pair, the function as the following "fulcrum" can be obtained more effectively. Next, with reference to FIGS. 7 to 10, the operation mode of the transfer device 1 of the present embodiment will be described. FIG. 7 is a schematic diagram showing the operation mode of the transfer device of the present embodiment. FIG. 7(A) is a view for explaining the operation of the holding device approaching the transfer object on the loading port at the transfer position. FIG. 7(B) is a view for explaining the operation of lifting the holding device by the lifting conveyor belt during the upward movement. FIG. 7(C) is a view for explaining the operation when the holding device is lifted to the reference upward position. FIG. 7(D) is a view for explaining the operation of the holding device during the further winding of the lifting conveyor belt. FIG. 7(E) is a view for explaining the operation of the holding device when the winding of the lifting conveyor belt is completed. FIG. 8 is a partial enlarged view of FIG. 7(C) for explaining in more detail the operation of the holding device at the reference upward position. FIG. 9 is a partial enlarged view of FIG. 7(D) for explaining in more detail the tilting operation of the holding device. FIG. 10 is a partial enlarged view of FIG. 7(E) for explaining in more detail the tilting operation of the holding device. Further, in FIGS. 7 to 10, the above-mentioned guide member 44 is simplified, and the concave portion (contacted portion) 44a opening downward toward it is shown as a triangular concave portion. First, as shown in FIG. 7(A), on the loading port 16, the wafer 22 is transferred to the open cassette 18 held in a horizontal state by the holding device 10 by a hand or the like of a processing device (not shown). Next, as shown in FIG. 7(B), by the rotational drive of the lifting rollers 26 and 30, the first and second lifting conveyor belts 12 and 14 are wound by the same amount, and the holding device 10 holding the open cassette 18 containing the wafer 22 is lifted. When it is lifted, the holding device 10 is maintained in a horizontal posture by the pressurization of the above-mentioned compression spring 52. Next, as shown in FIG. 7(C), at a predetermined rising position, the cylindrical portion 46a of the pin member 46 abuts against the concave portion 44a of the guide member 44. In the present embodiment, this predetermined rising position refers to the uppermost position where the holding device 10 holds a horizontal posture (horizontal position), and hereinafter it will be referred to as the "reference rising position". Next, after reaching the reference rising position shown in FIG. 7(C), the lifting rollers 26 and 30 are further rotationally driven to wind the first and second lifting belts 12 and 14 by the same amount. Then, as shown in FIG. 7(D), it becomes a state where the holding device 10 has an inclination angle α1 (for example, α1 = 3°). Further, as shown in FIG. 7(E), until the inclination of the holding device 10 reaches the final target angle α2 (for example, α2 = 6°), the first and second lifting belts 12 and 14 are wound by the same amount, and the winding is ended at this position. As described above, in the present embodiment, during the "rising period (lifting period)" (the period shown in FIGS. 7(A) to 7(C)) when the holding device 10 that holds the horizontal posture is lifted by winding the first and second lifting belts 12 and 14, although the first and second lifting belts 12 and 14 are wound, the holding device 10 is not lifted above it, and there may be a "tilting period" (the period shown in FIGS. 7(C) to 7(E)) in which the holding device 10 changes from the horizontal posture to the inclined posture. Hereinafter, with reference to FIGS. 8 to 10, the operation of the holding device 10 at the end time point of the "rising period" shown in FIG. 7(C) and the operation of the holding device 10 during the "tilting period" shown in FIGS. 7(D) and 7(E) will be described in more detail. First, as shown in FIG. 8, at the above-mentioned reference rising position, the holding device 10 rises, and the cylindrical portion 46a of the pin member 46 abuts against the concave portion 44a of the guide member 44. At this time, when the holding device 10 is viewed in side view (observed from the horizontal direction), as shown by the posture of the bottom plate 50 indicated by a chain line Lp0 (a line connecting the first position A and the second position B), it is in a horizontal posture. That is, the horizontal position / horizontal posture of the holding device 10 at the reference rising position is defined by the abutment of the pin member 46 and the guide member 44. More specifically, the uppermost rising position that maintains this horizontal posture of the holding device 10 is defined by the abutment of the pin member 46 and the guide member 44. Also, as described above, since the winding amounts of the first and second lifting belts 12 and 14 are the same, a chain line Lb0 connecting the lower end positions of the respective lifting belts 12 and 14 becomes horizontal. Also, at this time, the height S0 of the compression spring 52 is the same as the height when it was initially assembled or when the holding device 10 is in a horizontal posture. Next, as shown in FIG. 9, if the first and second lifting drive belts 12 and 14 (with the same winding amount for each) are further wound from the state of the reference rising position shown in FIG. 8, although a dotted line Lb1 connecting the lower end positions of the respective lifting drive belts 12 and 14 remains horizontal, relative to a dotted line Lb0 (the lower end position of the drive belt at the "reference rising position"), it is displaced upward by a distance D1 corresponding to its winding amount. Moreover, in this state, a line connecting the first position A and the second position B, that is, a dotted line Lp1, is inclined in a side view relative to the dotted line Lp0 at the above-mentioned reference rising position. Hereinafter, this mechanism will be described. First, as described above, by winding the first lifting drive belt 12, the first connecting member 36 fixed to the bottom plate 50 rises by an amount equal to its winding amount. At this time, the pin member 46 abuts against the concave portion 44a of the guiding member 44, and since the pin member 46 is fixed to the bottom plate 50, the bottom plate 50 (holding device 10) takes an inclined posture of rising toward the first position A as shown by a dotted line Lpl with the contact portion between the cylindrical portion 46a of the pin member 46 and the concave portion 44a of the guiding member 44 as the "fulcrum". On the other hand, since the winding amount of the second lifting drive belt 14 is the same as that of the first lifting drive belt 12, the second connecting member 40 rises by the same amount as the first connecting member 36. Here, in the present embodiment, the second connecting member 40 is displaceably mounted in the vertical direction on the bottom plate 50, and a compression spring 52 is assembled between the bottom plate 50 and the second connecting member 40. Therefore, as the second connecting member 40 rises, the compression spring 52 is compressed from the height S0 shown in FIG. 8 to the height S1 shown in FIG. 9, whereby its inclination (dotted line Lp1) of the bottom plate 50 is allowed. By the inclination allowing action of this compression spring 52, the holding device 10 takes an inclined posture of rising toward the first position A and descending toward the second position B. Furthermore, as in the above-described modification, when the pin member 46 is disposed at a position overlapping the second position B in a side view, in the side view, when observed from the horizontal direction, the fulcrum of the inclination of the bottom plate 50 coincides with the contact portion of the pin member 46 facing the guiding member 44. Therefore, in the case of this modification, the holding device 10 takes an inclined posture of rising at the first position A and staying at the second position B. Further, as in the above-described modification, when arranged in the order of the first position A, the second position B, and the pin member 46 in a side view, in the side view, when observed from the horizontal direction, the fulcrum of the inclination of the bottom plate 50 is located on the outer side relative to the second position B. Therefore, in the case of this modification, the holding device 10 takes an inclined posture of rising at the first position A and also rising at the second position B. Moreover, in this case, the rising amount of the second position B is smaller than the rising amount of the first position A. Next, as shown in FIG. 10, the first and second lifting belts 12 and 14 are further wound up by the same amount until the target tilt angle α2 is reached. At this time, although the dotted line Lb2 connecting the lower end positions of the respective lifting belts 12 and 14 remains horizontal, relative to the position at the "reference raised position" indicated by the dotted line Lb0, it is displaced upward by a distance D2 corresponding to the total winding amount from the reference raised position. Moreover, in this state, the posture of the holding device 10 represented by the dotted line Lp2 connecting the first position A and the second position B becomes an inclined posture relative to the horizontal posture of the dotted line Lp0 at the reference raised position in a side view by the mechanism described in FIG. 9. At this time, the compression spring 52 is further compressed to a height S2 (less than S1), whereby the inclination of the holding device 10 is allowed to be maintained. Further, when unloading, by simply feeding out the respective lifting belts 12 and 14 by an equal amount, the holding device 10 and the conveyed object, i.e., the wafer 22 (open cassette 18), become horizontal. Thereby, with a simple structure and using the same control method as the normal control of the lifting rollers 26 and 30, it is possible to incline the conveyed object only when the carriage moves. Next, the operation and effect of the overhead traveling type conveying device in the embodiment of the present invention will be described. First, the overhead traveling type conveying device 1 in the present embodiment and the modified example is an overhead traveling type conveying device 1 that travels on the overhead track 4 and conveys the article 22, and it includes: a carriage body (carriage body part) 2, a holding device 10 for holding the article, and a lifting device 8 for lifting the holding device 10 relative to the carriage body 2; the lifting device 8 includes: a first belt member (first suspension member) 12 and a second belt member (second suspension member) 14 for suspending the holding device 10, and drive devices 26, 30, 34 for winding and unwinding the first belt member and the second belt member; the holding device 10 includes: an abutting member (46) for the holding device 10 to abut against the carriage body 2 at a predetermined rising position (reference rising position) when rising relative to the carriage body 2; the carriage body 2 includes: an abutting member (44) for the abutting member 46 of the holding device 10 to abut against; the first belt member 12 suspends the holding device 10 at the first position A on the holding device; the second belt member 14 suspends the holding device 10 at the second position B on the holding device; the drive devices 26, 30 wind and unwind the first belt member 12 and the second belt member 14 by the same length; furthermore, it includes: when the first belt member 12 and the second belt member 14 are wound by the same length at a predetermined rising position (reference rising position) where the abutting member of the holding device 10 abuts against the abutting member of the carriage body 2, an allowable portion (such as a spring, rubber, etc.) 52 that allows the holding device 10 to tilt (α1, α2) with the abutting portion (46a, 44a) of the abutting member and the abutting member as the fulcrum. According to this embodiment of the configuration, regardless of the lifting distance (the winding amount of the belt member / suspension member), the holding device 10 can be tilted at a desired fixed tilt angle (α2). Also, in the present embodiment, since the abutting member 46 of the holding device 10 is provided between the first position A and the second position B when observed from the horizontal direction, when the first belt member 12 and the second belt member 14 are wound by the same length at a predetermined rising position (reference rising position), the allowable portion (52) allows the holding device 10 to tilt (α1, α2) in such a way that the first position A moves upward and the second position B moves downward with the abutting portion (46a, 44a) of the abutting member and the abutting member as the fulcrum, and thus it can more effectively make the holding device 10 tilt at the required fixed tilt angle (α2). Further, in the present embodiment, since the allowing portion (52) is provided with an elastic member (spring 52, rubber) that, when the first belt member 12 and the second belt member 14 are wound up by the same length at a predetermined rising position (reference rising position), allows the inclination of the holding device 10 with the contact portions (46a, 44a) of the contact member (46) and the contacted member (44) as the fulcrum through elastic deformation, it can more effectively allow the inclination of the holding device 10. Further, in the present embodiment, when the holding device 10 is not holding the articles 10 and 22, the elastic member 52 is contracted from its natural length. Therefore, the pressing force generated by the amount of contraction from the natural length is imparted to the holding device 10 by the elastic member 52, and when the holding device 10 holding the article (e.g., from the loading port 16) is lifted, it can suppress the inclination of the holding device 10. Further, in the present embodiment, since the contact member (46) of the holding device 10 and the contacted member (44) of the cart body 2 are at a predetermined rising position (reference rising position), and the horizontal position (Lp0) and the rising position (Lb0) of the holding device 10 are defined, the contact member and the contacted member, in addition to functioning as the "fulcrum" when the holding device 10 is inclined, also have a positioning function when the holding device 10 rises. Further, in the present embodiment, at the first position A of the holding device 10, a first connecting member 36 that connects the first belt member 12 to the bottom plate (base member) 50 of the holding device 10 is provided. At the second position B of the holding device 10, a second connecting member 40 that connects the second belt member 14 to the bottom plate 50 of the holding device 10 is provided. The first connecting member 36 is fixed to the bottom plate 50, and the second connecting member 40 is mounted on the bottom plate 50 so as to be relatively displaceable in the vertical direction with respect to the bottom plate 50. The allowing portion is provided with an elastic member (spring, rubber, etc.) 52 that is disposed between the bottom plate 50 and the second connecting member 40 and allows the relative displacement between the bottom plate 50 and the second connecting member 40. According to this embodiment of the configuration, the elastic member 52 bends under the force from the bottom plate 50 of the holding device 10 and the second connecting member 40 connected to the second belt member 14, thereby effectively allowing the inclination of the holding device 10. Further, in the present embodiment, the lifting device 8 is mounted on the cart body 2, and the contacted member 44 of the cart body 2 is mounted on the lifting device 8 mounted on the cart body 2. Also, the contact member 46 is a pin member 46 that protrudes upward, and the contacted member 44 is a guiding member 44 that is open downward and receives and supports the pin member 46, so that the inclination angle (α2) desired for the inclination of the holding device 10 can be more effectively fixed. 1: Overhead traveling type conveying device 2: Cart body 4: Track guide 6: Traveling mechanism 8: Lifting device 10: Holding device 12: First lifting conveyor belt (first suspension member) 12a: Lower end portion of the first lifting conveyor belt 12 14: Second lifting conveyor belt (second suspension member) 14a: Lower end portion of the second lifting conveyor belt 14 16: Loading port 18: Open cassette 20: Chuck 22: Wafer (article, conveyed object) 24: Opening 26, 30: Lifting rollers 28, 32: Idle pulleys 34: Drive shaft 36: First connecting member / first connecting bracket 36a, 40a: Fixed members 40: Second connecting member / second connecting bracket 44: Guide member (abutted member) 44a: Concave portion (abutted portion) 46: Pin member (abutting member) 46a: Cylindrical portion (abutting portion) 50: Bottom plate (base member) 52: Compression spring (permitting portion, pressure increasing member) A: First position B: Second position D1, D2: Winding amount of the lifting conveyor belt / rising amount of the holding device from the reference rising position Lb0, Lb1, Lb2: Line connecting the lower end positions of the first and second lifting conveyor belts Lp0, Lp1, Lp2: Line connecting the first position A and the second position B / tilted posture of the holding device S0, S1, S2: Height FIG. 1 is a side view showing a schematic configuration of an entire overhead traveling type conveying device according to an embodiment of the present invention. FIG. 2 is a left side view observed from the left side of a device showing a schematic configuration of a lifting device of the conveying device according to an embodiment of the present invention. FIG. 3 is a top view observed from above of a device showing a schematic configuration of a lifting device of the conveying device according to an embodiment of the present invention. FIG. 4 is a front view of a device showing a schematic configuration of a holding device according to an embodiment of the present invention. FIG. 5 is a left side view of a device showing a schematic configuration of a holding device according to an embodiment of the present invention. FIG. 6 is a rear view of a device showing a schematic configuration of a holding device according to an embodiment of the present invention. FIG. 7 is a schematic diagram showing an operation mode of the conveying device of the present embodiment. FIG. 7(A) is a diagram for explaining an operation when the holding device approaches a conveyed object on a loading port at a transfer position. FIG. 7(B) is a diagram for explaining an operation during the rising process of lifting the holding device by a lifting conveyor belt. FIG. 7(C) is a diagram for explaining an operation when the holding device is lifted to a reference rising position. FIG. 7(D) is a diagram for explaining an operation of the holding device during the process of further winding the lifting conveyor belt. FIG. 7(E) is a diagram for explaining an operation of the holding device when the winding of the lifting conveyor belt is completed. FIG. 8 is a partial enlarged view of FIG. 7(C) for explaining in more detail the operation of the holding device at the reference rising position. FIG. 9 is a partial enlarged view of FIG. 7(D) for explaining in more detail the tilting operation of the holding device. FIG. 10 is a partial enlarged view of FIG. 7(E) for explaining in more detail the tilting operation of the holding device. 1: Overhead traveling type conveying device 2: Trolley body 4: Track guide 6: Traveling mechanism 8: Lifting device 10: Holding device 12: First lifting conveyor belt (first suspension member) 14: Second lifting conveyor belt (second suspension member) 16: Loading port 18: Open cassette 22: Wafer (article, conveyed object) 26, 30: Lifting roller 36: First connecting member / first connecting bracket 40: Second connecting member / second connecting bracket 44a: Concave portion (abutted portion) 46a: Cylindrical portion (abutting portion) 50: Bottom plate (base member) A: First position B: Second position

Claims

1. A conveying device, which is an elevated conveying device that moves and conveys items on an elevated track; characterized in that: it comprises: a trolley body, a holding device for holding items, and a lifting device for raising and lowering the holding device relative to the trolley body; the lifting device comprises: a first suspension member and a second suspension member for suspending the holding device, and a drive device for winding and unwinding the first suspension member and the second suspension member; the holding device comprises: an abutting member that abuts against the trolley body at a predetermined rising position relative to the trolley body; the trolley body comprises an abutting member against which the abutting member of the holding device abuts; the first suspension member suspends the holding device at a first position, the second suspension member suspends the holding device at a second position, and the drive device winds or unwinds the first suspension member and the second suspension member by the same length. It further includes: a tolerance section; when the abutting member of the retaining device abuts to the predetermined rising position of the abutted member of the trolley body and the first suspension member and the second suspension member are wound up to the same length, it allows the retaining device to tilt by using the abutting part of the abutting member and the abutted member as a fulcrum.

2. As in request item 1, the conveying device, wherein, When viewed from the horizontal direction, the abutting member of the aforementioned retaining device is positioned between the first position and the second position. The allowable portion allows the retaining device to tilt when the first suspension member and the second suspension member are wound to the same length at the predetermined rising position, with the abutting part of the abutting member and the abutted member as the fulcrum, the first position is displaced upward and the second position is displaced downward.

3. The conveying device as requested in item 1 or 2, wherein, The aforementioned allowable part is equipped with an elastic member. When the first suspension member and the second suspension member are wound to the same length at the predetermined rising position, the retaining device is allowed to tilt by means of elastic deformation, using the contact point between the abutting member and the abutted member as a fulcrum.

4. As in request item 3, the conveying device, wherein, When the aforementioned retaining device is not holding the article, the aforementioned elastic member is compressed relative to its natural length.

5. The conveying device as requested in item 1 or 2, wherein, The abutting member of the aforementioned retaining device and the abutting member of the aforementioned trolley body are positioned at the aforementioned predetermined rising position, which defines the horizontal position and rising position of the aforementioned retaining device.

6. The conveying device as requested in item 1 or 2, wherein, At the first position of the aforementioned holding device, a first connecting member is provided to connect the first suspension member to the base member of the aforementioned holding device. At the second position of the aforementioned holding device, a second connecting member is provided to connect the second suspension member to the base member of the aforementioned holding device. The first connecting member is fixed to the aforementioned base member. The second connecting member is mounted on the aforementioned base member with relative displacement in the vertical direction relative to the aforementioned base member. The allowable portion includes an elastic member disposed between the aforementioned base member and the aforementioned second connecting member and allowing relative displacement between the aforementioned base member and the aforementioned second connecting member.

7. The conveying device as requested in item 1 or 2, wherein, The aforementioned abutting member is a pin member protruding upwards, and the aforementioned abutted member is a guide member that is open downwards and receives and supports the aforementioned pin member.

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