Source: http://www.google.com/patents/US5125149?ie=ISO-8859-1&dq=U.S.+patent+number+7,325,728
Timestamp: 2014-03-14 15:31:37
Document Index: 136219688

Matched Legal Cases: ['art 92', 'art 92', 'art 92', 'art 92', 'art 92', 'art 92', 'arts 92', 'art 92', 'art 92', 'arts 92', 'arts 92', 'arts 92', 'art 92', 'art 92', 'art 92', 'art 92', 'art 92', 'art 92', 'art 92']

Patent US5125149 - Method of accessing and assembling parts in an assembly apparatus ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsAn assembly (machining) apparatus and method for performing assembly or machining of an article. A first article supply device including a plurality of supply devices for supplying articles and a first robot for picking up the articles from the first article supply device to perform the assembly or machining...http://www.google.com/patents/US5125149?utm_source=gb-gplus-sharePatent US5125149 - Method of accessing and assembling parts in an assembly apparatus incorporating mobile robotsAdvanced Patent SearchPublication numberUS5125149 APublication typeGrantApplication numberUS 07/514,415Publication dateJun 30, 1992Filing dateApr 25, 1990Priority dateApr 28, 1989Fee statusLapsedPublication number07514415, 514415, US 5125149 A, US 5125149A, US-A-5125149, US5125149 A, US5125149AInventorsYusaku Azuma, Ryohei Inaba, Toshihiko Miura, Sachio UmetsuOriginal AssigneeCanon Kabushiki KaishaExport CitationBiBTeX, EndNote, RefManPatent Citations (27), Referenced by (33), Classifications (25), Legal Events (7) External Links: USPTO, USPTO Assignment, EspacenetMethod of accessing and assembling parts in an assembly apparatus incorporating mobile robotsUS 5125149 AAbstract An assembly (machining) apparatus and method for performing assembly or machining of an article. A first article supply device including a plurality of supply devices for supplying articles and a first robot for picking up the articles from the first article supply device to perform the assembly or machining are paired as an assembly unit, and a plurality of the assembly units are aligned. The apparatus also includes a buffer device for adjusting a difference in article assembly or machining time between the plurality of assembly units.
The automatic assembly system 1 comprises a pair of first and second automatic assembly apparatuses 2.sub.1 and 2.sub.2, a first coupling convey path 3.sub.1 for coupling the terminal end of the first automatic assembly apparatus 2.sub.1 and the starting end of the second automatic assembly apparatus 2.sub.2, and a second coupling convey path 3.sub.2 for coupling the terminal end of the second automatic assembly apparatus 2.sub.2 and the starting end of the first automatic assembly apparatus 2.sub.1, and constitutes a so-called closed-loop (endless) convey path.
Each of the automatic assembly apparatuses 2.sub.1 and 2.sub.2 receives parts from a large number of parts supply mechanisms 16 and 18 using a plurality of robots 22 (to be described later), and assembles these parts on a assembly jig 24. More specifically, the first assembly apparatus 2.sub.1 assembles a large number of assemblies which constitute a finished product, and the second automatic assembly apparatus 2.sub.2 receives the large number of assemblies assembled by the first automatic assembly apparatus 2.sub.1, and assembles these assemblies through a large number of parts to finally assemble the finished product.
The first coupling convey path 3.sub.1 conveys the large number of assemblies assembled by the first automatic assembly apparatus 2.sub.1 and placed on the jig tray T to the starting end of the second automatic assembly apparatus 2.sub.2. The second coupling convey path 3.sub.2 conveys the empty jig tray T to the starting end of the first automatic assembly apparatus 2.sub.1 to recover the jig tray T after the finally assembled finished product has been removed from the jig tray T at the terminal end of the second automatic assembly apparatus 2.sub.2. In other words, in the automatic assembly system 1, a finished product is assembled from a large number of parts on one jig tray T while the jig tray is endlessly conveyed.
The first automatic assembly apparatus 2.sub.1 is constituted by coupling first and second automatic assembly units 10.sub.1 and 10.sub.2 in tandem with each other, and the second automatic assembly apparatus 2.sub.2 is constituted by coupling third to fifth automatic assembly units 10.sub.3 to 10.sub.5 in tandem with each other.
The automatic assembly units 10.sub.1 to 10.sub.5 basically have the same arrangement, and each unit basically comprises one shuttle base 12, a shuttle 20 traveling along the shuttle base 12, one robot 22 and one assembly jig 24 which are mounted on the shuttle 20, and a plurality of parts supply mechanisms 16 and 18 which are independently and detachably disposed, as will be described in detail later. Note that in this embodiment, the shuttle bases 12 of the first and second automatic assembly units 10.sub.1 and 10.sub.2 constituting the first automatic assembly apparatus 2.sub.1 are connected to each other to constitute a continuous shuttle base connected body. The shuttle bases 12 of the third to fifth automatic assembly units 10.sub.3 to 10.sub.5 constituting the second automatic assembly apparatus 2.sub.2 are connected to each other to constitute a continuous shuttle base body.
In each of the automatic assembly units 10.sub.1 to 10.sub.5, for example, as shown in FIG. 2, each robot 22 has a travel range (access range) defined by an extending range of the corresponding shuttle base 12, and shuttles within this shuttle base 12.
The first automatic assembly apparatus 2.sub.1 comprises a first buffer mechanism 4.sub.1 for transferring, to the second automatic assembly unit 10.sub.2, the jig tray T on which an assembly assembled by the first automatic assembly unit 10.sub.1 is placed. The second automatic assembly apparatus 2.sub.2 comprises a second buffer mechanism 4.sub.2 for transferring, to the fourth automatic assembly unit 10.sub.4, the jig tray T on which a plurality of assemblies assembled up to the third automatic assembly unit 10.sub.3 are placed, and a third buffer mechanism 4.sub.3 for transferring, to the fifth automatic assembly unit 10.sub.5, the jig tray T on which a plurality of assemblies assembled up to the fourth automatic assembly unit 10.sub.4 are placed.
The above-mentioned first and second coupling convey paths 3.sub.1 and 3.sub.2 have substantially the same buffer function as that of the buffer mechanisms 4. A difference between the convey paths and the buffer mechanisms is that each buffer mechanism 4 is formed into a substantially U shape, while the first and second coupling convey paths 3.sub.1 and 3.sub.2 are linearly arranged.
The buffer mechanisms 4 (4.sub.1 to 4.sub.3) have the same arrangement, and a detailed arrangement thereof will be described later.
In the second automatic assembly apparatus 2.sub.2, as shown in FIG. 2, a plurality of reverse mechanisms 5 for reversing the vertical positional relationship of assemblies placed on the jig tray T are disposed at appropriate positions, e.g., at a total of three positions, as indicated by reference numerals 5.sub.1, 5.sub.2, and 5.sub.3 in this embodiment. Since the reverse mechanisms utilize known arrangements, a detailed description thereof will be omitted.
Description of Automatic Assembly Unit The overall arrangement of the automatic assembly units 10 (10.sub.1 to 10.sub.5) of this embodiment will be described below with reference to FIG. 3. In the following description, since the automatic assembly units 10.sub.1 to 10.sub.5 basically have the same arrangement, reference numeral 10 represents an automatic assembly unit to be described below.
In FIG. 6, reference symbol P.sub.1 designates a nonempty pallet which stores parts; and P.sub.0, an empty pallet in which parts are used up, and which becomes empty.
The second parts supply mechanism 18 comprises the pallet supply cart (to be simply referred to as a cart hereinafter) 92 for storing a plurality of pallets P. The cart 92 will be briefly described below. The cart 92 stacks and stocks a plurality of pallets P storing the same kind of parts, and separates nonempty pallets P.sub.1 one by one to align the separated pallet P.sub.1 at an accessible level position for the robot 22. The cart 92 receives and stacks empty pallets P.sub.0 in which parts are used up. The cart 92 incorporates a drive motor/sensor control mechanism (cart control mechanism) 92a for achieving the above-mentioned functions. More specifically, as shown in FIG. 5, the cart control mechanism 92a, connected to a power receiving terminal 92c, for controlling the operations of the cart 92 is arranged in a base frame 92b.
As described above, a movable area (access area) of the robot 22 corresponds to a range indicated by reference symbol A, which is a range defined by the distance from the center of the robot body 52, as shown in FIG. 6, when the robot 22 is located at a position S.sub.0 in FIG. 6. The parts pickup sections of the first and second parts supply mechanisms 16 and 18 are set within the range A, that is:
(1) a front half of a first cart 92.sub.1 (in the following description, reference numerals 92.sub.1 to 92.sub.10 are used when 10 carts 92 are to be identified), in other words, one nonempty pallet P;
(4) the parts pickup openings 70a of two tape cassettes 70.sub.1 and 70.sub.2 (in the following description, reference numerals 70.sub.1 to 70.sub.12 are used when 12 tape cassettes 70 are to be identified); and
The robot 22 has the same access area even when it is moved to any position. For example, the shuttle 20 indicated by an alternate long and short dashed line travels from a state at the travel start position S.sub.0 indicated by a solid line (i.e., a state opposing the first cart 92.sub.1) to a position S.sub.3 opposing the fourth cart 92.sub.4 along a direction of an arrow R in FIG. 6. Changes in access area of the robot 22 in this case from the case wherein the robot 22 was located at the position S.sub.0 are that:
(1) an accessible cart is changed from 92.sub.1 to 92.sub.4 ; and
(2) an accessible tape cassettes are changed from 70.sub.1 and 70.sub.2 to 70.sub.6, 70.sub.7, and 70.sub.8.
In this manner, the shuttle 20 is positioned in correspondence with each of the first to tenth carts 92.sub.1 to 92.sub.10 from the left end position S.sub.0 to states of S.sub.1, S.sub.2, . . . , S.sub.10 in FIG. 6, and the carts 92 and the tape cassettes 70 are arranged so that one of the carts 92.sub.1, 92.sub.2, . . . , 92.sub.10 and one to three of the tape cassettes 70.sub.1, 70.sub.2, . . . , 70.sub.12 can be accessed under the same positional condition.
As a result, when the shuttle 20 and the robot 22 are aligned at the position S.sub.0, as indicated by solid lines in FIG. 6, the light-receiving elements 88b and 88c receive light beams from the lamps 86 of the two tape cassettes 70.sub.1 and 70.sub.2 carried on the first carrier base 84, and the light-receiving element 98 receives light from the lamp 96 of the first cart 92.sub.1. Meanwhile, when the shuttle 20 and the robot 22 are conveyed to and stopped at the position S.sub.3, as indicated by alternate long and short dashed lines in FIG. 6, the light-receiving elements 88a, 88b, and 88c respectively receive light beams from the lamps 86 of the three tape cassettes 70.sub.6, 70.sub.7, and 70.sub.8 carried on the third carrier base 84, and the light-receiving element 98 receives light from the lamp 96 mounted on the fourth cart 92.sub.4.
A hatched portion in FIG. 6 indicates the field of view of the first camera 18 for checking the interior of the pallet P when the shuttle 20 is located at the position S.sub.0. This field of view is shifted upon movement of the shuttle 20, and always covers the nonempty pallet P.sub.1 side of at least the robot 22 side on the cart 92 corresponding to the stop position of the shuttle 20.
In a state shown in FIG. 7A, the shuttle 20 on which the robot 22 is arranged is stopped and aligned at a position where the robot 22 can access parts b(c) in the first cart 92.sub.1, and parts a(t) in the tape cassette 70.sub.1.
Before this assembly, whether or not supply preparation of parts a(t) and b(c) is completed is checked in a non-contact manner by detecting ON states of the lamps 86 of the first tape cassette 70.sub.1 and the lamp 96 of the cart 92 through the light-receiving elements 88a to 88c and 98 mounted on the shuttle 20 almost simultaneously with alignment of the shuttle 20 to the state shown in FIG. 7A, in other words, through the communication means.
In the first tape cassette 70.sub.1, after these pickup checking operations, the carrier tape 72 is conveyed by a given pitch by the self driving sources, and alignment preparation for a new part a(t).sub.n to be used next is started. This preparation need only be completed until the part a(t).sub.n is dealt in the next parts pickup cycle. When the preparation is completed, the lamp 86 is turned on.
The robot 22 is operated in response to a coordinate system obtained based on position information of a part b(c) checked by the first camera 26 for checking the interior of the pallet in the previous parts pickup cycle in the first cart 92.sub.1, thereby picking up the part b(c) from the pallet P. The pickup state is checked by the internal sensor of the finger unit 32. Thereafter, the swivel arms 36 and 54 are turned, thus conveying the picked up part b(c) to the assembly jig 24.
When the swivel arm 36 moves from a position above the pallet P storing the picked up part b(c), the position of a part b(c).sub.n to be picked up in the next cycle in the pallet P storing the picked up part b(c) in the immediately preceding cycle is checked by the first camera 26, arranged on the shuttle 20, for checking the interior of the pallet, and an image is stored in an image memory of an image processing unit in the control mechanism 28. Image processing after the image is stored, coordinate conversion to a coordinate system of the robot 22, and the like need only be completed when the part b(c).sub.n is dealt in the next cycle, and are processed to be parallel with the control operation of the robot 22.
Thereafter, the shuttle 20 is set and stopped in a state wherein the robot 22 can access parts c(c), d(t), e(t), and f(t) to be assembled next, as illustrated in FIG. 7B. At this stop position, the light-receiving elements 88a to 88c detect ON states of the lamps 86 of the corresponding second to fourth tape cassettes 70.sub.2, 70.sub.3, and 70.sub.4, and the light-receiving element 98 detects an ON state of the lamp 96 of the second cart 92.sub.2, thereby checking completion of supply preparation of the parts c(c), d(t), e(t), and f(t).
It is also checked if assembly of the picked up part b(c) in the immediately preceding cycle is completed on the assembly jig 24. Thereafter, the pickup operations of the parts c(c), d(t), e(t), and f(t) and assembly of these parts on the assembly jig 24 are performed in the same manner as in FIG. 7A. An image storing operation for checking the position of a part c(c).sub.n to be picked up in the next cycle is performed after the part c(c) is picked up, and the swivel arm 36 is moved toward the assembly jig 24. In the state shown in FIG. 7B, since the assembly of the parts d(t), e(t), and f(t) must be performed thereafter, completion of the pickup operation is checked by the internal sensor of the finger unit 32 after the part f(t) is picked up, and at the same time, the shuttle 20 starts movement in the direction R upon an instruction from the control mechanism 28 after the finger unit 32 is sufficiently moved upward not to collide against the fourth tape cassette 70.sub.4 if it is moved above the fourth tape cassette 70.sub.4. Thereafter, the shuttle 20 starts movement in the direction P upon an instruction from the control mechanism 28.
In the following description, various parts are represented by reference symbols a, b, c, d, . . . , currently assembled parts are designated by reference symbols a.sub.0, b.sub.0, c.sub.0, d.sub.0, . . . , and parts to be picked up in the next cycle are designated by a.sub.n, b.sub.n, c.sub.n, d.sub.n, . . . .
When the robot 22 picks up a part a.sub.0 in step S10, a sensor arranged in the finger unit 32 of the robot 22 checks completion of the pickup operation in step S12. In step S14, the swivel arm 36 is moved toward the assembly jig 24 to assemble the picked up part a.sub.0. If it is detected and recognized by the rotary encoder (not shown) incorporated in the driving motor for driving the swivel arm 36 in step S16 that the swivel arm 36 is moved toward the jig 24 and reaches a position where it does not interrupt the field of view of the first camera 26, the first camera 26 receives in step S18 an image of a part a.sub.n to be picked up by the robot 22 in the next cycle on the pellet P.
On the other hand, in parallel with step S18, in step S20, the robot 22 starts assembly of the part a.sub.0 on the assembly jig 24.
After the image receiving operation in step S18 is started, if completion of the image receiving operation of the part a.sub.n is detected in step S22, the shuttle 20 immediately begins to move in step S24 toward a part b to be accessed next. In parallel with step S24, in step S26, the position of the part a.sub.n is calculated based on the image information received in step S18.
In this calculation, the received image information of the part a.sub.n is stored in the image memory in the image processing unit of the control mechanism 28, and the image processing unit causes an image processing CPU to execute image processing and conversion processing to a robot coordinate system until the robot picks up the part a.sub.n in the next cycle. Upon completion of the calculation processing in step S26, the calculated data is stored in a parts position data storage section ax of a parts position data memory M in the image processing unit.
The robot 22 executes assembly of the part a in step S20 described above. If completion of the assembly is determined in step S30, position data of a part b.sub.0 to be picked up next is loaded from the above-mentioned parts position data memory M in step S32, and movement of the swivel arm 36 is started based on the loaded position data in step S34.
In synchronism with step S34, in the shuttle 20, it is checked in step S36 if movement of the shuttle 20 to an access point of the part b.sub.0 is completed. If completion of movement is determined in step S36, the robot 22 executes the pickup operation of the part b.sub.0 in step S38.
Basically, the control operations in steps S10 to S38 are repetitively executed. When the robot 22 picks up the part b.sub.0 in step S38 and completion of the pickup operation of the part b.sub.0 is detected in step S42, the swivel arm 36 is moved toward the jig 24 in step S44. If it is detected that the swivel arm 36 leaves a position above the pallet P upon this movement, the first camera 26 receives an image of a part b.sub.n to be picked up by the robot 22 in the next cycle in step S48, and at the same time, assembly of the part b.sub.0 is executed in step S50.
In step S52, image processing and conversion processing to a robot coordinate system is executed until the robot 22 picks up the part b.sub.n in the next cycle. In step S54, the position data of the part b.sub.n to be picked up next is stored in a parts position data storage section bx of the parts position data memory M.
The buffer mechanisms 4 (4.sub.1, 4.sub.2, 4.sub.3) will be described below with reference to FIGS. 9 to 12. Each buffer mechanism transfers a predetermined assembly from a jig mounting guide 68 on a predetermined shuttle 20 to a jig mounting guide 68 of the next shuttle 20 in units of the jig trays T, and absorbs a difference in assembly speeds of the robots of these shuttles 20, thereby setting a maximum assembly speed of each robot 22.
In the following description, these buffer mechanisms 4.sub.1, 4.sub.2, and 4.sub.3 have the same arrangement, and are represented by reference numeral 4. An automatic assembly unit 10 which delivers the jig tray T on which an assembly is placed is represented by adding a suffix "a", and an automatic assembly unit 10 which receives the jig tray T is represented by adding a suffix "b".
In the following description, reference symbol T.sub.a designates a jig tray at a reception position; T.sub.1, a jig tray at a first standby position; T.sub.2, a jig tray at a second standby position; T.sub.3, a jig tray at a third standby position; T.sub.b, a jig tray at a delivery position.
The stopper member 128 is fixed to the distal end of a piston rod 130a of a stopper cylinder 130 for driving the stopper member. When no jig tray T.sub.b is present at the delivery position, the stopper cylinder 130 retracts its piston rod 130a downward to allow conveyance of the jig tray T.sub.1 from the first standby position to the delivery position. When the jig tray T.sub.b is present at the delivery position, the cylinder 130 pushes up its piston rod 130a to lock conveyance of the jig tray T.sub.1 from the first standby position to the delivery position.
As shown in FIG. 11, a delivery tray sensor 132 is disposed on the guide member 102 on the mounting base 100. The delivery tray sensor 132 is turned on by the jig tray T.sub.b conveyed to the delivery position. When the delivery tray sensor 132 is turned on, the second lift cylinder 114 is operated to push up the delivery lifter 112, so that the tray T.sub.b at the delivery position is lifted to be separated from the travel belts 106. When a delivery signal is output to enable the delivery cylinder 124, the jig tray T.sub.b is immediately pushed out from the delivery position toward the next shuttle 20b.
When the delivery tray sensor 132 is turned off and an internal sensor (not shown) detects return of the delivery cylinder 124, the second lift cylinder 114 is operated to move the delivery lifter 112 downward to the level lower than the travel belts 116. In this manner, when the delivery lifter 112 is moved downward, the next jig tray T.sub.1 can be allowed to be conveyed to the delivery position.
A standby tray sensor 134 is disposed on the guide member 102. The standby tray sensor 134 is turned on by the jig tray T.sub.1 which is conveyed to the first standby position. In a state wherein the above-mentioned delivery tray sensor 132 is turned on, after the lapse of a predetermined period of time after the standby tray sensor 134 is turned on, the stopper cylinder 130 described above is driven, and pushes out the stopper member 128 to the locking position, thereby locking the jig tray T.sub.1 conveyed to the first standby position.
The stopper cylinder 130 is operated to return the stopper member 128 to its retracted position after the delivery tray sensor 132 is turned off, and the delivery lifter 112 is moved downward to the level lower than that of the travel belts 106. In this manner, when the stopper member 128 is returned to the retracted position, the jig tray T.sub.1 at the first standby position begins to be conveyed toward the delivery position.
A full sensor 136 is arranged on the guide member 102. The full sensor 136 is turned on by the third jig tray T.sub.3 which is conveyed onto the travel belts 106 and stands by to be adjacent to the immediately preceding tray T, as shown in FIG. 11. When the full sensor 136 is turned on, this means that no more jig trays T can stand by on the travel belts 106. Thus, the operation of the reception lifter 108 is inhibited to inhibit any more jig trays T from placing on the travel belts 106.
A reception sensor 138 is arranged on the guide member 102. The reception sensor 138 is turned on by the jig tray T.sub.a which is pushed out to the reception position. When the reception sensor 138 is turned on, the first lift cylinder 110 is operated to push down the reception lifter 108, thereby placing the jig tray T.sub.a pushed out to the reception position onto the travel belts 106. In this manner, upon travel of the travel belts 106, the jig trays T placed on the travel belts 106 can be conveyed toward the delivery position.
In a controller 150 of the buffer mechanism 4, in an initial state wherein no jig tray T is present on a buffer tray convey device (i.e., the pair of travel belts 106), the reception sensor 138 is kept off. The OFF signal of the sensor 138 is input to a counter C.sub.2 through an inverter, thereby enabling the counter C.sub.2. After a count operation by the counter C.sub.2 is completed, a count end signal is output to a driving device 110A for the first lift cylinder 110 to drive it. According to the operation of the first lift cylinder 110, the first lift cylinder 110 pushes up the reception lifter 108 to a level position higher than that of the travel belts 106. In this manner, a reception standby state at the reception position is set.
More specifically, when the tray exhaust start switch 140 is turned on, an ON signal of this switch 140 and an OFF signal of the reception sensor 138 are input to a first logic circuit 150A, and a high-level signal from the logic circuit 150A is input to a driving device 118A for the reception cylinder 118. Upon input of the high-level signal, the driving device 118A drives the reception cylinder 118 to push out the reception pusher 116 in the reception direction Q. In this manner, the jig tray T.sub.a is pushed out from the jig mounting guide 68 on the shuttle 20a. As a result, the jig tray T.sub.a is transferred onto the reception lifter 108 via the reception rails 104a (step S102).
When the jig tray T.sub.a is carried on the reception lifter 108 and is pushed by the reception pusher 116 to be transferred to a correct reception position where the sensor 138 is operated, the sensor 138 is turned on, thus completing the reception operation (step S103).
In response to an ON signal from the reception sensor 138, the first lift cylinder 110 moves the reception lifter 108 downward by the lift cylinder driving device 110A. As a result, the jig tray T.sub.a is placed on the traveling travel belts 106, and is conveyed toward the delivery position in the travel direction R upon travel of the travel belts 106 (step S104).
When the jig tray T.sub.a is conveyed from the reception position and the reception sensor 138 is turned off, the counter C.sub.2 measures a predetermined period of time, so that the first lift cylinder 110 pushes up the reception lifter 108, as described above, thus setting the reception standby state at the reception position again (step S105).
When no jig tray T.sub.b stands by at the delivery position, i.e., when the delivery sensor 132, the standby tray sensor 134, and the full sensor 136 are kept off, a reception standby state for the delivery position is set at the delivery position. In the reception standby state for the delivery position, the second lift cylinder 114 pushes down the delivery lifter 112 to a level position lower than the travel belts 106, and the delivery cylinder 124 sets the pusher 112 to be retracted from the delivery position (step S107).
In this manner, the jig tray T.sub.a is conveyed to the delivery position in the reception standby state. When the jig tray T.sub.a reaches the delivery position, the delivery tray sensor 132 is turned on (step S108).
A detection device 114B for detecting a moving position of the second lift cylinder 114 is connected to the cylinder 114. A second logic circuit 150B receives an ON signal from the delivery tray sensor 132 and a signal obtained by inverting an OFF signal (when the second lift cylinder 114 is in a push-down state, the detection device outputs the OFF signal) from the detection device 114B by an inverter. Thus, the second logic circuit 150B outputs a high-level signal. Upon reception of the high-level signal, a driving device 114A drives the second lift cylinder 114 to push up the delivery lifter 112 As a result, the jig tray T.sub.b at the delivery position is lifted upward to a level position higher than the travel belts 106 (step S109).
In this delivery operation, an ON signal from the tray loading start switch 142 is input to a delivery cylinder driving device 124A. Thus, the delivery cylinder 124 is driven to push out the delivery pusher 122 in the delivery direction S (step S112). Upon this push-out operation, the jig tray T.sub.b at the delivery position is conveyed to and set on the jig mounting guide 68b on the delivery shuttle 20b via the delivery rails 104b, thus completing delivery operation of one jig tray T (step S113).
When the jig tray T.sub.b is pushed out from the delivery position, the delivery tray sensor 132 is turned off, and the OFF signal and a position detection signal 124b from a cylinder position detection device 124B for the delivery cylinder 124 are input to a third logic circuit 150C. Thus, the third logic circuit 150C outputs a high-level signal. Upon reception of the high-level signal, a driving device 124A drives the delivery cylinder 124 to return the delivery pusher 122 in a direction opposite to the delivery direction.
Description of Buffer Stock Operation Mode In a convey operation of a jig tray T from the reception position to the delivery position, when the jig tray T.sub.b stands by at the delivery position, i.e., when the delivery tray sensor 132 is turned on, the buffer stock operation is executed.
The ON state of the delivery tray sensor 132 is checked (step S116). The next jig tray T is conveyed on the pair of travel belts 106 of the convey device of the buffer mechanism 4. Thus, the standby tray sensor 134 located on the upstream side of the delivery position is turned on (step S117), and outputs an ON signal. The ON signal from the delivery tray sensor 132 in step S116 and the ON signal from the standby tray sensor 134 are input to a fifth logic circuit 150E. Thus, the fifth logic circuit 150E outputs a high-level signal, thus causing a counter C.sub.1 to start a count operation (step S118).
A count end signal from the counter C.sub.1 is input to a stopper cylinder driving device 130A, and the stopper cylinder 130 pushes up the stopper member 128 (step S119), thereby locking the jig tray T.sub.1 in conveyance immediately before the delivery position. As a result, the jig tray T.sub.1 is locked by the stopper member 128 at the first standby position regardless of travel of the travel belts 106. In this manner, the buffer stock operation when the jig tray T.sub.b is left at the delivery position is completed, and a buffer standby state is set (step S120).
A delivery operation of the tray T.sub.b at the delivery position to the second robot 22b is executed in accordance with the buffer delivery operation mode shown in FIGS. 14A(a) and 14A(b) (step S121).
When the delivery operation of a tray at the delivery position is performed, the delivery tray sensor 132 is turned off. An inverted signal of the OFF signal from the sensor 132 and a detection signal 130b from a position detection device 130B for the stopper cylinder 130 are input to a sixth logic circuit 150F. Thus, the sixth logic circuit 150F outputs a high-level signal. Upon reception of the high-level signal, the driving device 130A drives the stopper cylinder 130, thereby releasing the locked state of the tray T.sub.1 by the stopper member 128 (step S122).
When the locked state by the stopper member 128 is released, the tray T.sub.1 at the standby position is conveyed to the delivery position upon travel of the pair of travel belts 106 of the convey device (step S123). Thereafter, the delivery standby state at the delivery position is set as described above (step S124).
Upon conveyance of a jig tray T from the reception position to the delivery position, when the jig tray T.sub.1 is in a standby state at the first standby position, the same buffer stock operation described above is executed at the second standby position set at the immediately upstream side of the first standby position. In this case, the second jig tray T.sub.2 is brought into contact with the jig tray T.sub.1 and is stopped and stands by at the second standby position.
Buffer Full Mode A full mode will be described below with reference to FIGS. 13 and 14C. In this mode, the four trays T.sub.b, T.sub.1, T.sub.2, and T.sub.3 sequentially stand by on the pair of travel belts 106 of the convey device of the buffer mechanism 4.
When the convey device becomes full, the full sensor 136 is turned on. When the full sensor 136 is turned on (step S125), the buffer full mode is set to prevent the following buffer stock. As a result, a jig tray T.sub.a is inhibited from being placed on the travel belts 106 in the delivery automatic assembly unit 10a.
When the full sensor 136 is turned on, a counter C3 starts counting. The counter C.sub.3 is used to distinguish the full mode of the buffer mechanism 4 from a normal article convey mode set when the buffer is not full.
When the buffer mechanism 4 is not full, an article passes by the full sensor 136 after it turns on the sensor 136 once. Therefore, only when the full sensor 136 outputs an ON signal after the lapse of a passage time of the jig tray T measured by the counter C.sub.3, a full checking unit 160 comprising the counter C.sub.3 and an eighth logic circuit 150H performs checking.
More specifically, the output signal from the counter C.sub.3 and a signal from the full sensor 136 are input to the eighth logic circuit 150H. According to these signal, the eighth logic circuit 150H outputs a high-level signal, thereby detecting a full state.
Furthermore, after transfer of the tray to the second robot at the delivery position, steps of the buffer stock mode described above with reference to FIG. 14B are executed (step S128). Along with the operation of the buffer stock mode, the tray T.sub.b shown in FIG. 11 is transferred by the travel belts 106 from the delivery position to the second robot; the tray T.sub.1, from the first standby position to the delivery position; the tray T.sub.2, from the second standby position to the first standby position; and the tray T.sub.3, from the third standby position to the second standby position.
When the tray T.sub.3 is conveyed from the third standby position to the second standby position, the full sensor 136 is turned off (step S129). The OFF signal from this sensor serves as a signal for canceling the inhibition operation by the inhibition unit 110C. As a result, the inhibition state of the reception lifter 108 is released (step S130).
In the embodiment described above, if the tray T.sub.b at the delivery position and the tray T.sub.1 at the first standby position are assumed to be conveyed in a so-called multiple collision state, a right side surface T.sub.b-1 (FIG. 15A) of the tray T.sub.b and a left side surface T.sub.1-1 (FIG. 15A) are in contact with each other, as shown in FIG. 15A. As a result, a contact pressure by a convey force of the travel belts 106 always acts on the tray T.sub.b at the delivery position from the right-hand side. The contact pressure is kept applied as long as the trays T.sub.b and T.sub.1 are in contact with each other even when the tray T.sub.b at the delivery position is set in a delivery operation state wherein it is moved upward from the convey surfaces of the travel belts 106 by the delivery lifter 112.
If the above-mentioned contact pressure is applied to the tray T.sub.b at the delivery position, the transfer position of the tray T.sub.b to be transferred is undesirably varied when the delivery pusher 122 transfers the tray T.sub.b in the direction of the arrow S.
For this reason, in the embodiment described above, the tray T.sub.b at the delivery position on the convey device is kept separated from the tray T.sub.1 at the first standby position, thus solving the above-mentioned problem.
In FIG. 15B, reference symbol P.sub.b denotes a delivery position; P.sub.1, a first standby position; and P.sub.2, a second standby position adjacent to the first standby position. Reference numeral 180 denotes a second standby position sensor for outputting an ON signal when a tray T is transferred to the second standby position P.sub.2.
The head portion of the stopper member 128 is located at a position where a distance (interval) ΔT can be set between the tray T.sub.b at the delivery position P.sub.b and the tray T.sub.1 at the first standby position P.sub.1.
A description will be started from a state wherein the tray T.sub.2 is conveyed to the second standby position P.sub.2.
The tray T.sub.b at the delivery position P.sub.b is transferred in the direction of the arrow S upon operations of the delivery lifter 112 and the delivery pusher 124. When there is no tray T.sub.b at the delivery position P.sub.b, the stopper member 128 is released, and the tray T.sub.1 at the first standby position P.sub.1 is conveyed to the delivery position P.sub.b. When the tray T.sub.b at the delivery position P.sub.b is transferred, the delivery tray sensor 132 is turned off, and the fourth counter C.sub.1 starts the counting operation in response to an inverted signal of an OFF signal from the sensor 132. After the lapse of a predetermined period of time, the stopper cylinder 130 is operated in response to a counter output. In this manner, the tray T.sub.2 located at the second standby position P.sub.2 so far by the stopper member 128 is conveyed to the first standby position P.sub.1 and is locked at this position. The tray T.sub.2 conveyed to the first stopper position P.sub.1 and the tray T.sub.1 conveyed to the delivery position P.sub.b can keep an interval of ΔT by the stopper member 128, as shown in FIG. 15B.
In the upper half of FIG. 16, a first robot 22.sub.3 picks up respective parts from a plurality of tape cassettes of a second supply mechanism 6a, also picks up respective parts from a plurality of pallets of a first supply mechanism 8a, and is moved by its assembly movement stroke l.sub.1 along a shuttle base (rail) 12.
In the parts assembly process by the first robot 22.sub.3, if the assembly movement stroke of the second parts supply mechanism 6a is decreased upon modification of a product obtained by assembling parts or a unit and that of the first robot 22.sub.3 becomes l.sub.2, a necessary movement stroke of the first robot 22.sub.3 is decreased by l.sub.1 -l.sub.2 =l.sub.3.
Note that assembly movement strokes l.sub.4 and l.sub.5 of a second robot 22.sub.4 are also determined by the number of parts to be supplied and alignment intervals of the supply mechanisms as in the assembly movement strokes l.sub.1 and l.sub.2 of the first robot 22.sub.3.
The second embodiment is to provide a parts supply method which can cope with an assembly mode of changing a movement stroke of the robot 22.sub.3 of the first assembly unit
According to the second embodiment, in order to cope with a change in assembly movement stroke of a robot in the first assembly unit described above, in an assembly or machining apparatus having a buffer mechanism which is arranged between assembly movement stroke paths of the first and second robots 22.sub.3 and 22.sub.4, and comprises a convey means for receiving trays on which parts are placed from the first robot 22.sub.3 and delivering them to the second robot 22.sub.4, the buffer mechanism is movable in accordance with the movement strokes of the first and second robots 22.sub.3 and 22.sub.4 during assembly or machining of parts, thereby solving the above-mentioned problem.
In FIG. 17, reference numeral 160 denotes a car unit as a moving mechanism of the buffer mechanism 4. The car unit 160 comprises wheels 160a and 160b for moving the buffer mechanism itself, a motor M.sub.1 disposed in the car unit 160, and driving force transmission mechanisms 160c and 160d for transmitting the driving force of the motor to the wheels 160a and 160b. The driving force transmission mechanisms 160c and 160d comprise driving force transmission chains in the second embodiment.
A first lift cylinder 110 for driving a reception lifter 108 and a second lift cylinder 114 for driving a delivery lifter 112 are housed and held in the car unit 160. The buffer mechanism 4.sub.2 is supported and placed on the car unit 160 as a whole through support members 162A and 162B.
As has been described above with reference to the upper half of FIG. 16, upon modification of an assembly or machining mode of the first assembly unit, the position of the modified buffer mechanism 4.sub.2 must often be moved, as shown in the lower half of FIG. 16.
When the buffer mechanism must be moved in this manner, according to this embodiment, as shown in FIG. 17, the wheels 160a and 160b are driven by the motor M.sub.1 incorporated in the car unit 160. In this manner, the position of the buffer mechanism 4.sub.2 can be changed from the position shown in the upper half of FIG. 16 to the position shown in the lower half of FIG. 16.
In this manner, in the second embodiment, since the buffer mechanism 4 is placed on the car unit 160 as the moving mechanism, the buffer mechanism 4 and the second robot side can be moved in a direction of an arrow in the lower half of FIG. 16. Upon movement of the buffer mechanism 4, the assembly process by the first robot 22.sub.3 and the assembly (machining) process by the second robot 22.sub.4 can be continuously performed through the buffer mechanism 4.
The robots 22.sub.3 and 22.sub.4 can be used with optimal movement strokes, and a task loss in robot operations caused by wasteful movement can be eliminated.
In FIG. 18A, as in the second embodiment, reference symbol P.sub.b denotes a delivery position; P.sub.1 and P.sub.2, first and second standby positions, respectively: P.sub.3, a third standby position; and P.sub.a, a reception position. Reference numeral 138 denotes a reception sensor for, when a tray is transferred to the reception position P.sub.a, outputting an ON signal.
Reference numeral 132 denotes a delivery sensor for, when a tray is conveyed to the delivery position P.sub.b, outputting an ON signal; 134, 180, and 136, first, second, and third standby tray sensors for, when trays are respectively conveyed to the first, second, and third standby positions, outputting ON signals.
FIG. 18A illustrates an initial state wherein no tray is present in the buffer mechanism 4. FIG. 18B illustrates a state wherein a tray is transferred to the reception position P.sub.a. FIG. 18C illustrates a transient state wherein a tray is being transferred from the reception position P.sub.a to the delivery position P.sub.b. FIG. 18D illustrates a state wherein a tray is located at the delivery position P.sub.b. FIG. 18E illustrates a state wherein the next tray is transferred to the reception position P.sub.a while the previous tray is present at the delivery position P.sub.b.
In the characteristic feature of the third embodiment, the convey speed of a tray is increased during a period from the state in FIG. 18B to a state in FIG. 18D, and the convey speed of a tray is decreased in other periods. More specifically, the convey speed is increased from the time when a tray is transferred to the reception position P.sub.a, the reception sensor 138 is turned on, there are no trays at other positions in the buffer mechanism 4, and all the delivery tray sensor 132, the first, second, and third standby sensors are OFF to the time when the tray at the reception position P.sub.a is transferred to and reaches the delivery position P.sub.b, and the delivery tray sensor 132 generates an ON signal.
The tray transferred onto the reception lifter 108 is conveyed to the delivery position P.sub.b by the travel belts 106. While the tray is being conveyed from the reception position P.sub.a to the delivery position P.sub.b, the sensors 136 and 134 are turned off, on, and off by the tray. In this case, the motor M is rotated at high speed by the signal holding circuit 166.
As shown in FIG. 18E, when the first tray reaches the delivery position P.sub.b to turn on the sensor 132, and the second tray is transferred onto the reception lifter 108 to turn on the reception sensor 138, signals from the sensors 132 and 138 are input to a tenth logic circuit 150J.
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feeEffective date: 20040630Jun 30, 2004LAPSLapse for failure to pay maintenance feesJan 28, 2004REMIMaintenance fee reminder mailedDec 27, 1999FPAYFee paymentYear of fee payment: 8Oct 26, 1995FPAYFee paymentYear of fee payment: 4Oct 12, 1993CCCertificate of correctionApr 25, 1990ASAssignmentOwner name: CANON KABUSHIKI KAISHA, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:INABA, RYOHEI;UMETSU, SACHIO;MIURA, TOSHIHIKO;AND OTHERS;REEL/FRAME:005291/0414Effective date: 19900406RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google