This is a 371 national phase application of PCT/JP2008/066485 filed 5 Sep. 2008, claiming priority to Japanese Patent Application No. 2007-231424 filed 6 Sep. 2007, the contents of which are incorporated herein by reference.
The present invention relates to an automatic transfer apparatus equipped with a self-propelled transfer vehicle that has a connecting portion connecting with a carriage carrying workpieces or loads and that runs by self-propulsion along a predetermined path.
There has been conventionally known an automatic transfer apparatus equipped with a self-propelled transfer vehicle such as a tractor type self-propelled vehicle (hereinafter called a carriage tractor) that is attachable and detachable through a connecting portion to a carriage loaded with workpieces or loads and runs by self-propulsion along a predetermined path by using guiding means such as magnetic information laid on a floor surface while towing the carriage, or a carrier type self-propelled vehicle that is integrated through a connecting portion with a carriage loaded with workpieces or loads and runs by self-propulsion along the predetermined path by using the guiding means such as the magnetic information laid on the floor surface.
Now, as shown in
In recent years, effective use of the automatic transfer apparatus tends to increase. Moreover, it is sought to downsize the carriage tractor so as to enable running in a small space for higher efficiency, and it is also sought to achieve lower cost.
However, in order to configure the carriage tractor (2WD+2WS) 50 having the complicated structure as shown in
It should be noted that, as a related art of the automatic transfer apparatus, Patent Document 1 describes a four-wheel steering type unmanned transfer vehicle that is an unmanned transfer vehicle switchable between travel and traverse. The unmanned transfer vehicle is provided, on the lower surface thereof, with four running wheels having steering means for making steer angles of the wheels controllable independently of each other, and two of the running wheels arranged on the diagonal line of the transfer vehicle are provided with running drive motors so as to enable travel and traverse, thereby maintaining equilibrium of driving force with respect to the transfer vehicle and obtaining running stability.
However, in the invention of Patent Document 1, because the four running wheels of the transfer vehicle are provided with the steering means making the steer angles of the wheels controllable independently of each other, the structure of the transfer vehicle becomes complicated, disabling the downsizing and the cost reduction, thus failing to eliminate the problem described above.
In view of the problems described above, it is an object of the present invention to provide an automatic transfer apparatus that enables running of a self-propelled transfer vehicle in the forward-reverse direction and the traverse direction while simplifying and downsizing the structure of the self-propelled transfer vehicle such as a carriage tractor.
In order to solve the problems described above, an automatic transfer apparatus of the present invention is characterized in that: a displacement restricting means is provided for restricting lateral displacement of a carriage in its running direction when a self-propelled transfer vehicle runs in a traverse direction; the displacement restricting means is provided with a pair of carriage position holding guides that holds a position of the carriage on a traverse guide path where the self-propelled transfer vehicle runs in the transverse direction, or a drive wheel provided at the self-propelled transfer vehicle is composed of a drive wheel unit having a pair of right and left wheels rotating independently of each other; the drive wheel unit is provided at one place in a substantial center of the bottom of the self-propelled transfer vehicle; and the direction of the drive wheel unit is converted by differentiating rotational speeds of each of the wheels.
Consequently, the automatic transfer apparatus is capable of enabling the running of the self-propelled transfer vehicle in the forward-reverse direction and the traverse direction while simplifying and downsizing the structure of the self-propelled transfer vehicle.
Note that various forms of the automatic transfer apparatus of the present invention and operations thereof will be described in detail in the following items of exemplary forms of the invention.
Several forms of the invention that are recognized to be capable of being claimed for patent in the present application (hereinafter may be called “claimable invention”) will be exemplified and described below. Note that, similarly to the claims, the forms are classified into items, and the items are assigned with numbers and described in the form of citation of other items as required. This is solely for the purpose of facilitating understanding of the claimable invention, and not for limiting the combination of the components composing the claimable invention to those described in the items below. That is, the claimable invention should be interpreted in the light of the description associated with each item, of embodiments, and so on. As far as conforming to such an interpretation, not only a form provided by adding another component to a form of each item but also a form provided by removing a component from a form of each item can serve as a form of the claimable invention. Note that among the items listed below, each of items (1) to (5) corresponds to each of claims 1 to 5, respectively.
(1) An automatic transfer apparatus equipped with a self-propelled transfer vehicle that runs, by using a travel magnetic tape and a travel indication marker laid along a predetermined path, along the predetermined path in a forward-reverse direction and a traverse direction, and has a connecting portion connecting with a carriage is characterized in that: a displacement restricting means is provided for restricting lateral displacement of the carriage in its running direction when the self-propelled transfer vehicle runs in a traverse direction; the displacement restricting means is provided with a pair of carriage position holding guides that holds a position of the carriage on a traverse guide path where the self-propelled transfer vehicle runs in the transverse direction, or a drive wheel provided at the self-propelled transfer vehicle is composed of a drive wheel unit having a pair of right and left wheels rotating independently of each other; the drive wheel unit is provided at one place in a substantial center of the bottom of the self-propelled transfer vehicle; and the direction of the drive wheel unit is converted by differentiating rotational speeds of each of the wheels.
Accordingly, in the automatic transfer apparatus according to item (1), because the displacement restricting means is capable of restricting the lateral displacement of the self-propelled transfer vehicle and the carriage with respect to the running direction thereof when the self-propelled transfer vehicle runs in the traverse direction, there is no need to increase driving force of the self-propelled transfer vehicle by increasing the number of drive wheels and so on, thus enabling to simplify the structure of the self-propelled transfer vehicle. Further, since the displacement restricting means is structured by including the pair of carriage position holding guides that holds the position of the carriage on the traverse guide path on which the self-propelled transfer vehicle runs in the traverse direction, it is possible to easily restrict the lateral displacement of the self-propelled transfer vehicle and the carriage in their running directions with a simple structure when the self-propelled transfer vehicle runs in the traverse direction. Still further, since the drive wheel unit is provided at only one place in the self-propelled transfer vehicle, the structure of the self-propelled transfer can be further simplified. Moreover, running motors are respectively connected to the pair of right and left wheels of the drive wheel unit, so that the direction of the drive wheel unit can be converted by differentiating the rotational speeds of the running motors.
(2) The automatic transfer apparatus according to item (1) is characterized in that a detecting sensor detecting the travel magnetic tape is built into a front portion or a rear portion in a forward direction of a drive wheel, and, based on detection of the travel magnetic tape by the detecting sensor, the direction of the drive wheel is converted to either of the forward-reverse direction and the traverse direction.
Accordingly, in the automatic transfer apparatus according to item (2), because the direction of the drive wheel is converted to either of the forward-reverse direction and the traverse direction based on the detection of the guiding means by the detecting sensor, there is no need to newly provide a component such as a steering control motor or a steering angle sensor for controlling the direction of the drive wheel, thus further enabling to simplify the structure of the self-propelled transfer vehicle.
(3) The automatic transfer apparatus according to any one of items (1) to (2) is characterized in that the self-propelled transfer vehicle is a carriage tractor that is connected to the carriage in a detachable manner and tows the carriage, and the carriage tractor and the carriage are respectively provided with connecting portions through which the carriage tractor is connected near the substantial center of the bottom of the carriage.
Accordingly, in the automatic transfer apparatus according to item (3), in the case that the self-propelled transfer vehicle is the carriage tractor that tows the carriage, because the carriage tractor is connected to the carriage through the connecting portions near the substantial center of the bottom of the carriage, it is possible to minimize the lateral displacement of the carriage tractor and the carriage with respect to the running direction thereof when the carriage tractor runs in the traverse direction.
(4) The automatic transfer apparatus according to any one of items (1) to (3) is characterized in that the carriage position holding guides are composed of: a pair of guide plates that is arranged upright from each side of the floor surface of the traverse guide path through the travel magnetic tape and extends in the same direction as that of the travel magnetic tape; and a plurality of rotatable rollers that are provided on the surface of the guide plates along the direction in which the travel magnetic tape extends and make contact with the both lateral surfaces of the shorter sides of carriage bodies of the carriages.
(5) The automatic transfer apparatus according to any one of items (1) to (3) is characterized in that the carriage position holding guides are composed of: a pair of guide plates that is arranged upright from each side of a floor surface of the traverse guide path through the travel magnetic tape and extends in the same direction as that of the travel magnetic tape; and a pair of rotatable rollers that is provided at a front and a back of the carriage along a direction in which the travel magnetic tape extends, the rotatable rollers each rotated along the pair of guide plates.
According to the present invention, it is possible to provide an automatic transfer apparatus that enables the running of the self-propelled transfer vehicle in the forward-reverse direction and the traverse direction while simplifying and downsizing the structure of the self-propelled transfer vehicle such as the carriage tractor.
a)-1(f) show schematic diagrams illustrating an automatic transfer apparatus according to an embodiment of the present invention.
a)-4(c) show three orthographic views of a pin engaging member composing a connecting portion of a carriage of the automatic transfer apparatus.
a)-1(e) show schematic diagrams illustrating a related art automatic transfer apparatus.
1 Automatic transfer apparatus, 2 Travel magnetic tape, 2a Forward-reverse guide path, 2b Traverse guide path, 3 Carriage tractor (self-propelled transfer vehicle), 4 Carriage, 7 Drive wheel unit (drive wheels), 8 Wheel (drive wheel), 12 Magnetic detection sensor unit, 13a to 13c Magnetic detection sensors, 15 Connecting portion, 16a and 16b Connecting portions, 19 Connection pin, 18 Pin driving mechanism, 30 Pin engaging hole, 31 Pin engaging member, 35 Displacement restricting means, 36 Carriage position holding guide, 36a Guide plate, 36b Rotatable roller
Best modes for carrying out the present invention will be described in detail below based on
Note that, although the automatic transfer apparatus 1 according to the embodiment of the present invention employs as the self-propelled transfer vehicle the carriage tractor 3 that is connected to the carriage 4 in a detachable manner and tows the carriage 4, the present invention may obviously be applied to a carrier type self-propelled vehicle that is integrated with the carriage 4 through a connecting portion.
As shown in
Note that, in the description below, the words “front” and “rear” used for describing arrangement of component members and so on are used in the sense of the forward-reverse running direction of the carriage tractor 3. In addition, the word “lateral” is used in the sense of the direction intersecting with the running direction of the carriage tractor 3.
As shown in
In addition, the travel indication markers (not shown) are installed in a plural number at intervals along the travel magnetic tape 2. The system of the travel indication markers is divided into an absolute addressing system in which the markers themselves have a plurality of travel indications and a relative addressing system in which the markers themselves do not have the travel indications but the carriage tractor 3 has a traveling program, using the markers for counting up in the traveling program.
The carriage tractor 3 runs by self-propulsion along the travel magnetic tape 2 and the travel indication markers by using a magnetic detection sensor unit 12 and a travel indication marker detection sensor (not shown) installed at a front portion or a rear portion in the forward direction of a drive wheel unit 7. One piece of the drive wheel unit 7 is provided at the substantial center of the bottom of a carriage tractor body 6. The drive wheel unit 7 is structured such that running motors (not shown) are respectively connected to a pair of wheels 8, 8 provided on the right and the left so as to rotate the wheels 8, 8 independently. In addition, the carriage tractor 3 is capable of running in the forward and the reverse directions by forward and reverse rotations of the running motors and by fixed/swivel switching control of idler wheels 10a to 10d.
Moreover, the carriage tractor 3 is provided with the idler wheels 10a to 10d at four corners of the bottom of the carriage tractor body 6. Each of the idler wheels 10a to 10d is set as a swivel idler wheel that is freely revolvable about a vertical axis, or as a fixed idler wheel that is fixed so as to be oriented in the forward-reverse direction, at appropriate times.
Specifically, as shown in
For example, a case will be described in which the idler wheels 10a and 10b are set as fixed wheels.
When a cam 66 is rotated about a rotation axis M1 by controlling a clamping motor 65 in the wheel switching unit, the wheel switching plates 60 move in the front-rear direction (upper-lower direction viewed in the drawing) of the carriage tractor 3 while being restricted by guide rollers 67 and guides 68. Then, when the wheel switching plates 60 move in the front-rear direction, the positioning rollers 63 come into contact with U-shaped grooves 61 of the wheel switching plates 60 and move along the U-shaped grooves 61, thereby orienting directions of the wheels W in the front-rear direction. Subsequently, when the positioning rollers 63 have finally engaged with positioning notches 62 provided in the wheel switching plates 60, the directions of the wheels W are fixed in the state of being oriented in the front-rear direction. Then, the idler wheels 10a and 10b function as fixed wheels.
On the other hand, when switching the idler wheels 10a and 10b to the swivel wheels, the wheel switching plates 60 are moved in the direction separating from the positioning rollers 63 of the wheel holding portions 64 (downward viewed in the drawing). As a result, the idler wheels 10a and 10b are freed from the constrained state as fixed wheels, thereby subsequently functioning as swivel wheels.
As shown in
Usually, as shown in
As shown in
Then, when the motor 20 rotates the cam 21, the connection pin 19 can protrude from and recede into the carriage tractor body 6 through the cam follower 22 and the connecting member 23.
As shown in
In addition, the carriage 4 is provided with connecting portions 16a and 16b arranged in the front-rear direction that connect with the carriage tractor 3 near the substantial center of the bottom of the carriage body 24. For example, as shown in
In addition, as shown in
The displacement restricting means 35 is structured by including a pair of carriage position holding guides 36, 36 that makes contact with both lateral surfaces of the shorter sides of the carriage body 24 of the carriage 4, on the traverse guide path 2b along which the carriage tractor 3 runs in the traverse direction while towing the carriage 4.
The each carriage position holding guide 36 is composed of: a guide plate 36a that is arranged upright from the floor surface of the traverse guide path 2b and extends in the same direction as that of the travel magnetic tape 2 (traverse guide path 2b); and rotatable rollers 36b that are provided as a plurality on the surface of the guide plate 36a along the direction in which the travel magnetic tape 2 extends and make contact with one side of the lateral surfaces of the shorter sides of the carriage body 24 of the carriage 4.
Next, operation of the automatic transfer apparatus 1 according to the embodiment of the present invention will be described based on
First of all, as shown in
Then, in the state in which the front portion of the carriage tractor 3 protrudes from the front end of the carriage 4, the carriage tractor 3 runs on the travel magnetic tape 2 extending in the forward-reverse direction and on the travel indication markers while towing the carriage 4. In this state, the two idler wheels 10a and 10b on the front side of the carriage tractor 3 are set as swivel idler wheels, and the two idler wheels 10c and 10d on the rear side of the carriage tractor 3 are set as fixed idler wheels that are fixed so as to be oriented in the forward-reverse direction.
It should be noted that, when the carriage tractor 3 runs on the travel magnetic tape 2 while towing the carriage 4, the carriage tractor 3 runs while the three magnetic detection sensors 13a to 13c of the magnetic detection sensor unit 12 (refer to
In addition, the carriage tractor 3 runs by detecting the plurality of travel indication markers arranged at intervals along the travel magnetic tape 2 and following the travel indications thereof. For example, if the travel indication markers employ the relative addressing system, the carriage tractor 3 is installed with the traveling program in which each of the travel indications has been entered at the address number of each of the travel indication markers. Then, every time when the carriage tractor 3 passes each of the travel indication markers, the address number for the travel indication markers is counted up, and the carriage tractor 3 runs according to the travel indication corresponding to the address number of the travel indication marker passed.
Next, when the carriage tractor 3 runs in the traverse direction (traverse guide path 2b) converted from the forward-reverse direction (forward-reverse guide path 2a) while towing the carriage 4, the connection pin 19 of the carriage tractor 3 is first pulled out of the pin engaging hole 30 of the connecting portion 16a on the front side of the carriage 4 and retracted into the carriage tractor body 6 in the state of
Next, as shown in
That is, by differentiating the rotational speeds of the wheels 8, 8 of the drive wheel unit 7 oriented in the forward-reverse direction, the wheels 8, 8 are revolved about a vertical axis from the state in which the three magnetic detection sensors 13a to 13c are in the detection state of OFF, ON, and OFF in the corresponding order, through the process in which all of the magnetic detection sensors 13a to 13c are in the detection state of OFF, until the three magnetic detection sensors 13a to 13c are placed again in the detection state of OFF, ON, and OFF in the corresponding order, thus converting the direction of the drive wheel unit 7 by approximately 90° from the forward-reverse direction to the traverse direction.
Subsequently, all of the idler wheels 10a to 10d of the carriage tractor 3 that have been set as the fixed idler wheels are newly set as the swivel idler wheels.
Next, by driving the wheels 8, 8 of the drive wheel unit 7 of the carriage tractor 3, the carriage tractor 3 is run from the position of
Then, the carriage tractor 3 runs in the traverse direction towing the carriage 4, while all of the idler wheels 10a to 10d of the carriage tractor 3 that are newly set as the swivel idler wheels and all of the idler wheels 25a to 25d of the carriage 4 that have already been set as the swivel idler wheels are oriented in the same direction (traverse direction) as that of the drive wheel unit 7. At this time, although a lateral displacement operation occurs in the carriage tractor 3 and the carriage 4 with respect to the running direction thereof, the both lateral surfaces of the shorter sides of the carriage 4 are made contact with the pair of carriage position holding guides 36, 36, that is, the rotatable rollers 36b, 36b that are provided as a plurality on the surfaces of the pair of guide plates 36a, 36a along the direction of the traverse guide path 2b. Therefore, the carriage tractor 3 and the carriage 4 run in the traverse direction without being laterally displaced with respect to the running direction thereof.
Next, after the carriage tractor 3 and the carriage 4 complete to run in the traverse direction, the direction of the drive wheel unit 7 is turned clockwise to be converted by approximately 90° from the traverse direction to the forward-reverse direction while differentiating again the rotational speeds of the wheels 8, 8 of the drive wheel unit 7 of the carriage tractor 3, as shown in
That is, the wheels 8, 8 are revolved about the vertical axis from the state in which the three magnetic detection sensors 13a to 13c are in the detection state of OFF, ON, and OFF in the corresponding order, through the process in which all of the magnetic detection sensors 13a to 13c are in the detection state of OFF, until the three magnetic detection sensors 13a to 13c are placed again in the detection state of OFF, ON, and OFF in the corresponding order, thus converting the direction of the drive wheel unit 7 by approximately 90° from the traverse direction to the forward-reverse direction.
Next, from the state of
Then, as shown in
As described above, in the automatic transfer apparatus 1 according to the embodiment of the present invention, the carriage tractor 3 is provided with the connection pin 19 (connecting portion 15) that is connected to the carriage 4 near the substantial center of the bottom of the carriage 4, and, on the other hand, the carriage 4 is provided with the pin engaging hole 30 (connecting portion 16b) that is connected to the carriage tractor 3 near the substantial center of the bottom of the carriage 4. In addition, the traverse guide path 2b that allows the carriage tractor 3 to run in the traverse direction is provided with the pair of carriage position holding guides 36, 36 (displacement restricting means 35) that restricts the lateral displacement of the carriage 4 with respect to the running direction thereof when the carriage tractor 3 runs in the traverse direction while towing the carriage 4.
Consequently, in the automatic transfer apparatus 1, when the carriage tractor 3 runs in the traverse direction (traverse guide path 2b) converted from the forward-reverse direction (forward-reverse guide path 2a) while towing the carriage 4, the carriage tractor 3 and the carriage 4 run in a manner being restricted in lateral displacement with respect to the direction of running in the traverse direction. Thus, the carriage tractor 3 is capable of running in the forward-reverse direction and the traverse direction while simplifying and downsizing the carriage tractor 3 without complicating the structure thereof.
Note that, in the automatic transfer apparatus 1 according to the embodiment of the present invention, as shown in
In addition, although the pair of carriage position holding guides 36, 36 is structured in a manner making contact with the both lateral surfaces of the shorter sides of the carriage 4 so as to hold the position of the carriage 4, the guides 36, 36 may be structured in a manner making contact with the both lateral surfaces of the shorter sides of the carriage tractor 3 so as to hold the position of the carriage tractor 3.
Moreover, in the automatic transfer apparatus 1 according to the embodiment of the present invention, when the carriage tractor 3 runs in the traverse direction while towing the carriage 4, the connection pin 19 of the pin driving mechanism 18 provided in the carriage tractor 3 is engaged with the pin engaging hole 30 of the pin engaging member 31 provided near the substantial center of the bottom of the carriage 4, thus connecting the carriage tractor 3 with the carriage 4 by the engagement at one place. However, engaging means for engaging between the carriage tractor 3 and the carriage 4 may employ either of two modes shown in
That is, as shown in
Alternatively, as shown in
By structuring the engaging means as described above, when the carriage tractor 3 runs in the traverse direction while towing the carriage 4, integration between the carriage tractor 3 and the carriage 4 can be further enhanced than that in the mode in which the carriage tractor 3 and the carriage 4 are connected by engaging the connection pin 19 of the carriage tractor 3 with the pin engaging hole 30 near the substantial center of the bottom of the carriage 4, as shown in
Note that, in the automatic transfer apparatus 1 according to the embodiment of the present invention, if the travel magnetic tape 2 is laid on the floor surface in the shape of H as shown in
Number | Date | Country | Kind |
---|---|---|---|
2007-231424 | Sep 2007 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2008/066485 | 9/5/2008 | WO | 00 | 3/5/2010 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2009/031707 | 3/12/2009 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
5901805 | Murakami et al. | May 1999 | A |
6237504 | Tanahashi et al. | May 2001 | B1 |
6481521 | Sugiyama et al. | Nov 2002 | B2 |
Number | Date | Country |
---|---|---|
58-116259 | Jul 1983 | JP |
59-195463 | Nov 1984 | JP |
1989-16967 | Jan 1989 | JP |
1-266056 | Oct 1989 | JP |
5-108155 | Apr 1993 | JP |
5-112238 | May 1993 | JP |
8-123550 | May 1996 | JP |
11-265211 | Sep 1999 | JP |
2000-330635 | Nov 2000 | JP |
2006-31343 | Feb 2006 | JP |
Number | Date | Country | |
---|---|---|---|
20100212984 A1 | Aug 2010 | US |