Abstract:
In a device for controlling the drive of mechanisms operating separately from one another, the object is to minimize the operating effort and expense of driving alternatively operating mechanisms. Furthermore, it is ensured by the device that the mechanisms are only allowed to be put into operation if they are in a specific state and that this state is maintained throughout their operation. The device has power transmission capabilities different from one another for adjusting the control system to different states of the mechanisms. Arrangements provided for this purpose operate in different settings, determined by control signals, of which a first setting prevents a power transmission and further settings respectively permit power transmission to one of the mechanisms. The arrangement for power transmission is equipped with a signal-receiving device, with which a reception of the control signals dependent on the state of the mechanisms takes place. The signal-receiving device is connected to a signal generator, which generates the control signals for the power transmission. Such devices may be used for operating transfer devices for transferring objects between two locations, such as are required in semiconductor factories and by manufacturers for equipping such factories.

Description:
This application is a division of application Ser. No. 09/170,575, filed Oct. 13, 1998, now U.S. Pat. No. 6,205,881. 
    
    
     BACKGROUND OF THE INVENTION 
     a) Field of the Invention 
     The invention relates to a device for controlling the drive of mechanisms operating separately from one another, the control being adapted to different states of the mechanisms. 
     Such devices may be used, inter alia, for transfer devices for transferring objects between two locations, such as are required in semiconductor factories and by manufacturers for equipping such factories. The objects may be, for example, transport containers for material transport; the locations may be processing stations or depositing locations spatially removed from one another. 
     b) Description of the Related Art 
     In semiconductor factories, it is customary to transport the substrates to be processed in open or closed containers between different locations and different processing devices by transport devices specially designed for the purpose. In such cases, the handling of the containers during the required loading and unloading operations is to take place in an ergonomic way for the operating personnel. The latter is of special significance with the increasing size of substrates to be processed and the associated increase in size and weight of the containers. 
     Known simple transport carriages have a simple storage capability for the containers and require loading and unloading by the operating personnel. 
     Such a solution is important particularly whenever a transport system has to be used as an interim solution for an automatic system, because the containers to be transported exceed the ergonomically admissible limit. Specifically in the early and medium-term construction phase of semiconductor factories, manually operated transport systems are required in order to optimize fitting out and work procedures. However, such interim solutions usually rule out fully automatic systems with complicated and expensive electronics and sensor systems, for reasons of cost. This also applies to a mobile loading device according to U.S. Pat. No. 5,570,990 in the form of a carriage having a multi-member, swivelling transport arm, the members of which are pivotally connected to one another by joints and which is fastened to the upper end of a vertically adjustable shaft. The swivelling transport arm serves for transporting SMIF containers to a semiconductor processing installation and back to the carriage. For this purpose, the containers are seized by a gripper and set down at a depositing location of the semiconductor processing installation by a swivelling movement. The return transport takes place in the reverse way. Means for communication between the semiconductor processing installation and the carriage control monitor the procedures. While the operating personnel has to perform the movements with the transport arm in the x-y plane by turning the joints between the members of the transport arm without additional aids, a motor-driven auxiliary device is provided to relieve the work involved in the case of heavier items for the z movement of the transport arm. 
     It is disadvantageous that operating procedures separate from one another are required for different directions of the transport movement. This makes both the working sequence and the constructional design of the transporting device complicated and consequently costly. 
     As already described in U.S. patent application Ser. No. 08/977,588, it is often advantageous when using simple transport carriages to provide mechanisms in duplicate for the containers. If the transporting carriage is brought up to a processing device for loading and unloading, it is always possible to put into operation just the mechanism which is aligned with the processing device as the reference location. If one of the mechanisms is in operation, it is intended that the transport carriage be hindered from being able to move away from the reference location. 
     Both for reasons of expense and for reasons of user friendliness, it is desirable if just the actuation of a single drive element enables the operating personnel to meet these requirements. 
     OBJECT AND SUMMARY OF THE INVENTION 
     The primary object of the invention is therefore to keep down the operating effort and expense of driving alternatively operating mechanisms. Furthermore, it is to be ensured that the mechanisms are only allowed to be put into operation if they are in a specific state and that this state is maintained throughout their operation. 
     According to the invention, a device which has power transmission capabilities different from one another for adjusting the control system to different states of the mechanisms is provided. Means provided for this purpose operate in different settings, determined by control signals, of which a first setting prevents a power transmission and further settings respectively permit power transmission to one of the mechanisms. The means for power transmission are equipped with a signal-receiving means, with which a reception of the control signals dependent on the state of the mechanisms takes place. The signal-receiving means are connected to a signal generator, which generates the control signals for the power transmission. In a preferred design, the mechanisms serve for transferring items, for which purpose their alignment with respect to a reference location and a coupling at that location are required. 
     To maintain and to discontinue the coupling state of the mechanisms, the device also includes means for generating further signals, of which a first signal characterizes the power transmission to one of the mechanisms and a second signal characterizes an interruption in the power transmission. While the first signal prevents a change in state of the mechanism which has been put into operation, the second signal allows a change in state. 
     The mechanisms are advantageously fastened on a mobile base. A blocking device on the mobile base, which prevents or allows a movement away from the reference location, is connected to a device for the signal transmission for the first and second signals. It is also of advantage if the signal generator is in connection with movable coupling elements on the mobile base, which elements engage in fixed coupling elements on the reference location for the purpose of alignment and coupling. 
     The invention is explained more fully with reference to the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows mechanisms for transferring items, the said mechanisms being carried by a mobile base; 
     FIG. 2 shows a coupling mechanism for the mobile base; 
     FIG. 3 shows a coupling interface for the coupling of the mobile base; 
     FIG. 4 shows the coupling operation for assuming an ultimate coupling position; 
     FIG. 5 shows the linking of a control device with a signal generator for generating status signals on the coupling state and an immobilizer; 
     FIG. 6 shows parts of an immobilizer for preventing and enabling the moving of the object away from the destination; 
     FIG. 7 shows the control device in an exploded representation; 
     FIG. 8 shows the control device in a perspective representation from below; 
     FIG. 9 shows a section through the control device in a state in which there is no force transmission to one of the rollers; 
     FIG. 10 shows a section through the control device in a state in which there is force transmission to the upper roller; and 
     FIG. 11 shows a section through the control device in a state in which there is force transmission to the lower roller. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The mobile base represented in FIG. 1 in the form of a manually guided vehicle includes on a frame  1  a plate  2  with two mechanisms  3 ,  4  for the transfer of items, and a drive element  5 . The drive element  5  in the present exemplary embodiment is a simple hand crank, but may also be replaced by another suitable element for supplying energy. For force transmission to the respective mechanism  3  or  4 , a control device  37  according to FIGS. 7 to  11 , which is essential for the subject matter of the invention, is provided. The vehicle is placed before a loading and unloading station  6  as the destination to which an item to be transported, such as a container  7  for example, is to be transferred or from which it is to be removed. 
     Particularly suitable containers serve for receiving substrates (semiconductor wafers, reticles and templates) or other flat objects with a lateral opening, by which the container  7  can be coupled to the loading and unloading station  6 . The transfer of the container  7  to a receiving element  8  takes place with the aid of one of the mechanisms  3 ,  4 . In the present case, it is the mechanism  4 , which is already in a partially extended state. The other mechanism  3 , on the other hand, is retracted and is in its starting position. For oriented setting down, in the bottom of the container  7  and in the receiving element  8  aligning elements shaped to fit one another, in the form of grooves (not represented) and engaging pins, are provided in a three-point formation. 
     The container  7 , shown only in a very simplified form in FIG. 1, is structurally designed in such a way that the load-bearing parts of the mechanisms  3 ,  4  are not hindered in their horizontal movement. This concerns both the movement of the mechanism  4  after setting down the container  7  and the functional sequence for its return transport from the receiving element  8  to the vehicle. 
     It goes without saying that the destination is not restricted to the loading and unloading station  6  shown in this exemplary embodiment, but may also comprise other locations within the range of action of the vehicle. 
     First, the structural design and operating principle of an aligning and coupling device provided for the vehicle but not shown in FIG. 1 is to be described in more detail with reference to FIGS. 2 to  4 , since this device provides essential functional prerequisites for the operating principle of the control device  37 . 
     According to FIG. 2, the aligning and coupling device includes a coupling mechanism, which is fitted in the lower section of the vehicle and faces the destination. On a baseplate  9  and on a carrier rail  10  there are provided fixed roller carriers  11  for receiving guide rollers  12 , which fix the minimum distance of the vehicle from a coupling interface present at the destination. Shafts  17 ,  18 , which can rotate about their longitudinal axes X 1 —X 1 , X 2 —X 2 , X 3 —X 3 , X 4 —X 4 , and rotatable positioning and locking shafts  19 ,  20  are led out through bearing bushes  13 ,  14 ,  15 ,  16  in the carrier rail  10  and carry at their ends lying outside the vehicle two types of elements with which the vehicle can be coupled at the coupling interface. In addition to the rotational movement, the shafts  17 ,  18 ,  19 ,  20  can also execute a linear movement along their longitudinal axes X 1 —X 1 , X 2 —X 2 , X 3 —X 3 , X 4 —X 4 . The paired design of coupling element ensures the alignment of two mechanisms with respect to the destination. A first type of coupling elements comprises pairs of rollers each with a larger docking roller  21 ,  22  and a smaller docking roller  23 ,  24 , the axes of rotation of which Y 1 —Y 1 , Y 2 —Y 2  are directed perpendicularly with respect to the longitudinal axes X 1 —X 1 , X 2 —X 2  and which enclose the shafts  17 ,  18  between them. A second type of coupling elements comprises star-shaped positioning and coupling wheels  25 ,  26 , the notches  27 ,  28  of which form the engaging components. 
     Returning pins  29 , which protrude from the carrier rail  10 , engage in the notches  27 ,  28  of the positioning and coupling wheels  25 ,  26  when there is a rearward movement of the positioning and locking shafts  19 ,  20  and establish a defined angular position of the positioning and coupling wheels  25 ,  26 , which is assigned to a starting position. For this purpose, the star-shaped components of the positioning and coupling wheels  25 ,  26  are shaped in a suitable way. 
     According to FIG. 3, the coupling interface includes a guide rail  30  and a coupling bolt  31  as fixed elements. Only the coupling bolt  31  is movable, for adjusting purposes, in a rail  32  for fixing the ultimate coupling position. Once the adjustment has been completed, this element is fixed as well. The rail  32  is directed parallel to the guide rail  30 , which is made essentially as a U-profile and has a flange  33  for the guide rollers  12  to bear against. 
     The guide rail  30 , provided in a fixed location at the destination, allows a movement in a first direction along its longitudinal extent and blocks a movement perpendicularly to this direction. As a result, the vehicle, approaching the coupling interface with its coupling mechanism, is aligned parallel to the guide rail  30  as a result of the rolling of the guide rollers  12  on the flange  33 . Of the flanges of the guide rail  30 , one flange  34 , which is facing the vehicle during its approach, is of a smaller height than the other flange  35 , although both protrude above the rail  32 . 
     The differences in height between the flanges  34  and  35  ensure reliable docking of the appropriately designed coupling mechanism, in particular of the docking rollers  21 ,  22 ,  23 ,  24 , the axes of rotation of which Y 1 —Y 1 , Y 2 —Y 2  are, in the uncoupled state, directed parallel to the longitudinal extent of the guide rail  30  and parallel to the plane of movement of the vehicle. Once the guide rollers  12  are bearing against the rail  32 , the shafts  17 ,  18  are extended until the docking rollers  21 ,  22 ,  23 ,  24  butt against the flanges  35 . A 90° rotation of the shafts  17 ,  18  about their longitudinal axes X 1 —X 1 , X 2 —X 2  causes the rollers  21  and  23  to be placed between the two flanges  34  and  35  of the guide rail  30 . The vehicle can then be moved in the direction of the longitudinal extent of the guide rail  30  and is fixed in the direction perpendicular thereto. For docking, the working steps described are executed essentially in the reverse order. 
     The ultimate coupling position, in which one of the mechanisms  3  or  4  is aligned with respect to the destination, is assumed by one of the positioning and coupling wheels  25  or  26  being brought is into engagement with the coupling bolt  31 . FIG. 4 illustrates this procedure for the positioning and coupling wheel  25 , which, positioned by means of the rail  32 , initially assumes the angular position of the starting position. During the movement of the vehicle along the guide rail  30 , when it reaches the ultimate coupling position, the positioning and coupling wheel  25  finds the coupling bolt  31  and places itself around the latter with one of the notches  27  by a 45° rotation. 
     The different angular positions of the positioning and coupling wheel  25  in the uncoupled state (left-hand and central positions in FIG. 4) and in the coupled state (right-hand position in FIG. 4) are used for signal formation as changes in state of the movable elements. 
     The angular positions assumed by the positioning and coupling wheels  25  and  26  are recorded by a signal generator  36 , included in FIG. 5, to distinguish between the uncoupled state and the coupled state, and are transformed in such a way that it is also possible to distinguish between the two positioning and coupling wheels  25  and  26 . Each of these positioning and coupling wheels  25 ,  26  is assigned to one of the mechanisms  3 ,  4  via a control device  37 , the signal emitted comprising complete information on the coupling state and the position of the coupling. The signal fed to the control device  37  initiates a transmission of the drive force from the drive element  5  to the coupled mechanism  3  or  4 . 
     For this purpose, the signal generator  36  is designed in such a way that the positioning and locking shafts  19 ,  20  include cam elements  38 ,  39 , on which rotatably fastened signalling rollers  42 ,  43  rest at the ends of signalling levers  40 ,  41 . Of the cam elements  38 ,  39 , alternately provided raising portions  44  and lowering portions  45  for the signalling rollers  42 ,  43  correlate with the angular position of the respective positioning and coupling wheel  25 ,  26 . Axes of rotation X 5 —X 5 , X 6 —X 6  at the signalling levers  40 ,  41  are situated in such a way that the ratios of the lever arms of the two signalling levers  40 ,  41  differ. While the lever arms on the signalling lever  40  are approximately the same in the present example, the signalling lever  41  has a much shorter lever arm on the side of its signalling roller  43  than on its other side. Changes in the vertical position of the signalling rollers  42 ,  43  bring about different deflections at the free lever arm ends  46 ,  47 , which deflections are transmitted to the control device  37  through a first control rod  48 . 
     The signal generator  36  is designed in such a way that three different signals can be fed to the control device  37 . A first signal characterizes a state in which the vehicle has not accomplished a coupling with either of the mechanisms  3 ,  4  at the destination. In this state, the positioning and coupling wheels  25 ,  26  assume the angular position represented in FIG. 5, assigned to the starting position. Both signalling rollers  42 ,  43  are resting on the lowering portions  45  of the cam elements  38 ,  39 , whereby the free lever arm ends  46 ,  47  stay in their lower position and raise the first control rod  48  the most. If a coupling with one of the positioning and coupling wheels  25 ,  26  then takes place, the respective wheel is turned through 45° and one of the raising portions  45  of the cam element  38  or  39  raises the signalling roller  42  or  43 . If the positioning and coupling wheel  25  comes into action for the coupling, the first control rod  48  will be lowered downward by a smaller amount than in the case of the positioning and coupling wheel  26 , due to the difference which exists between the lever arm ratios of the signalling levers  40 ,  41 . Of course, it is possible to generate electrical signals in a suitable manner instead of mechanical signals. 
     In addition to the signal generator  35  represented in FIG. 5, the coupling mechanism also includes an immobilizer  49 , according to FIG. 6, which prevents or enables a moving away of the vehicle from the destination on the basis of a signal made available on the operating state of the mechanisms  3 ,  4 . For this purpose, the positioning and locking shafts  19 ,  20  include blocking wheels  50 ,  51 , on which there rest, with the force of springs  56 ,  57 , locking rollers  54 ,  55  which are rotatably fastened to locking levers  52 ,  53 . During the rotation of one of the positioning and coupling wheels  25  or  26  about the coupling bolt  31 , a detent force has to be overcome, which facilitates the locating of the coupling bolt  31  and the recognition of the ultimate coupling position. The upward and downward movement of the locking levers  52 ,  53 , caused by the rotation of the blocking wheels  50 ,  51 , can of course be controlled by various forms of the blocking wheels  50 ,  51 . The locking levers  52 ,  53 , adjustable about the axes of rotation X 7 —X 7 , X 8 —X 8  are suitable, when in an arrested position, for preventing a rotation of the positioning and locking shafts  19 ,  20 , due to the resting of the locking rollers  54 ,  55  on the blocking wheels  50 ,  51 , and consequently for preventing a movement of the vehicle away from the ultimate coupling position. Provided for this purpose is a blocking element  59 , which is rotatably mounted in a mount  58  and on which a vertically displaceable second control rod  60  acts. In its upper position, the second control rod  60  turns the blocking element  59  under the locking levers  52 ,  53  and prevents their movement. In the lower position, the movement is enabled. From the second control rod  60  there is, according to FIG. 5, a connection to the control device  37 , from where the signal on the operating state of the mechanisms  3 ,  4  is sent. 
     The control device  37 , the structural design and operating principle of which are illustrated by FIGS. 7 to  11 , includes as carrying elements an upper carrier plate  61  and a lower carrier plate  62 , the distance between which is determined by spacers  63  and which are held together by connecting elements  64 . Centrally made bores  65 ,  66  in the carrier plates  61 ,  62  serve for receiving bearings  67 ,  68 , which allow an internally hollow drive shaft  69  to rotate freely, a restraining ring  70  preventing the drive shaft  69  from falling out. A drive roller  71 , to which a force transmission takes place from the drive element  5  through a suitable force-transmission element (not shown), is in fixed connection with the drive shaft  69  and passes on to the latter the force supplied to it. A spacer  72  prevents contact with the fixed part of the bearing  68 . The free space between the carrier plates  61 ,  62  serves for receiving a first running roller  73  and a second running roller  74 , which are displaceable on the drive shaft  69  by being fastened on bearing bushes  75 ,  76 . For the transmission of the torque from the drive shaft  69  to the running rollers  73 ,  74 , and consequently to the transfer mechanisms  3 ,  4 , there is provided a control shaft  77 , which is displaceable in the cavity of the drive shaft  69  and, by virtue of its shaping and two different positions, is suitable for pressing spherical driving elements  79 ,  80 , contained in holes  78  in the wall of the drive shaft  69 , into recesses of the bearing bushes  75 ,  76  of the running roller  73  or  74  to be driven along. A third position of the control shaft  77  is provided for the purpose of pressing further driving elements  81  partially out of the drive shaft  69  into an interlocking plate  82 , rigidly connected to the carrier plate  59 , so that the drive shaft  69  is blocked. The three positions of the control shaft  77  correlate with the settings of the signal generator  36 , for which purpose the first control rod  48  is in connection with the control shaft  77 . The control shaft  77  is also secured by a restraining ring  83 , here against falling out from the drive shaft  69 . 
     In addition to the controlling of the force transmission from a drive to two mechanisms, to be selected separately from each other, on the basis of an external signal, the control device  37  also has the task of itself providing a signal, which characterizes the operating state of the two mechanisms. There is also an alternative possibility to generate electronical signals. The signal is intended for the actuation of the immobilizer  49 . If one of the two mechanisms  3 ,  4  is in operation, the vehicle must not be moved away from the destination. Only when both mechanisms  3 ,  4  are not in operation, i.e. when no container transport is taking place, may the vehicle be moved to another destination. 
     For this purpose, according to FIG. 8 there is fastened on the lower carrier place  62  a mount  84 , which carries an interlocking lever  86  in a joint  85 . While an interlocking roller  87  is rotatably secured to one end of the lever, the other end of the lever has a pin, on which the second control rod  60  acts. Furthermore, the drive roller  71  is fixedly connected to an interlocking flange  88 , which includes a locking notch  89  in the region of its edge. When neither of the mechanisms  3 ,  4  are being operated, the interlocking roller  87  lies in the locking notch  89 . The second control rod  60  is located in its lower position, in which the movement of the immobilizer  49  is out of operation. If the drive roller  71  is set in motion, to actuate one of the mechanisms  3 ,  4 , the interlocking roller  87  is lifted out of the locking notch  89 , whereby the other end of the interlocking lever  86  is raised, with the second control rod  60  fastened thereto. As a consequence, the immobilizer  49  blocks the movement of the positioning and locking wheels  19 ,  20 , as already described. 
     The torque transmission in the control device  37  is explained by FIGS. 9 to  11 . If the vehicle is not connected to the coupling interface present at the destination, operation of the mechanisms  3 ,  4  is to be prevented. The control rod  48  and the control shaft  77 , connected to the latter, assume their uppermost positions, which corresponds to the representations in FIGS. 5 and 9. The profile made in the control shaft  77  includes alternately regions of larger shaft diameter  90  and regions of smaller shaft diameter  91 , of which one of the regions  90  presses the driving elements  81  into recesses  92  provided in the interlocking plate  82  and blocks the drive shaft  69 . 
     In FIG. 10, the control shaft  77  is in a central position, which is brought about by the positioning and coupling wheel  25  being active for the coupling and by the control rod  60  being adjusted vertically by the signalling lever  40 . The driving elements  79  are pressed out of the drive shaft  69  into recesses in the bearing bush  75 , whereby a transmission of the torques to the running roller  73  is ensured. 
     In FIG. 11, the driving elements  80  are in connection with the bearing bush  76 , so that a transmission of the torques to the running roller  74  can take place. The present, lower position of the control shaft  77  is a consequence of the coupling of the positioning and coupling wheel  26  to the coupling interface and is produced by the adjustment of the control rod  60  via the control lever  41 . 
     While the foregoing description and drawings represent the present invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the true spirit and scope of the present invention.