Abstract:
An automatic device for handling objects comprises gripping means attached to a guiding element contacting the object, an actuator connected to the external means transporting the device, and a switching mechanism that alternately changes the status of the pickup device between an object-engaging and respectively object-disengaging status each time the guiding element reaches the end-of-travel position to an object holder. A single external axial movement is performed for both transporting the pickup device and actuating the switch and the grippers. An original pickup device with radially gliding pierced grippers crossed by curved arms attached to the axially moving actuator is disclosed, as well as a simplified object-handling robot and methods for using them, with emphasis to CD/DVD handling applications.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional patent application serial No. 60/556,857 filed Mar. 27, 2004 
                                                 References Cited, U.S. Patent Documents                                4253695   March, 1981   Blaive et al.   294/95;                   294/86.25; 294/110.1       4411576   October, 1983   Smith et al.   414/225.       4676710   June, 1987   Shiraishi   414/225.       5165340   November, 1992   Karlyn et al.   101/126.       5275424   January, 1994   Watanabe   279/2.       5503446   April, 1996   De Jong   294/94.       5698030   December, 1997   Rubenchik   118/500.       5797639   August, 1998   Zorzenon   294/110.1; 294.112       5873692   February, 1999   Costas.       5897153   April, 1999   Philipps   294/93; 294/95       5946216   August, 1999   Hollerich   364/478.       5997204   December, 1999   Ducrocq       6111847   August, 2000   Assadian   369/36.       6141298   October, 2000   Miller   369/30.       6220640   April, 2001   Jensen   294/93; 294/100       6257636   July, 2001   Hovis.   294.110.1; 294/82.32;                   294/116       6321649   November, 2001   Vangen   101/35; 101/4;                   206/307; 206/308.1       6532198   March, 2003   Miller       6547296   April, 2003   Perkitny   294/16; 294/28; 294/110.1               et al.                  
 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to automated devices and equipment for handling objects, with emphasis to devices and equipment used for handling information-storage medium objects such as compact discs.  
         [0003]     Many technologies require objects to be automatically and repetitively transported to/from specified locations in order to be processed. A wide diversity of pick-up devices and specialized equipment for transporting and processing such objects has been developed during the last two decades within the media industry, for processing of recordable information carriers like CD and DVD. Some of the most relevant ones related with the invention disclosed here are referenced in the patent list included.  
         [0004]     Various solutions are used for engaging/disengaging the objects to be transported: vacuum driven suction devices (U.S. Pat. No. 6,141,298), protruding grippers attempting to grasp the object from beneath (U.S. Pat. Nos. 5,275,424, 5,503,446, 5,897,153, 5,946,216, 6,220,640) or, for bored objects, friction grippers pushed against the inner wall of the hole of the object (U.S. Pat. Nos. 5,873,692, 6,111,847). Most known solutions require means for transporting the pick-up device against the object holder and, respectively, separate means for actuating the picker in order to engage or disengage the object. Regularly the transport arm has to carry not only the pickup device but its electromechanical actuators and associated sensors, too, along a large rigid frame or shaft, exceeding the height of the object stacks (U.S. Pat. Nos. 5,698,030, 5,873,692, 5,914,918, 5,946,216, 6,111,847, 6,141,298, 6,321,649, 6,532,198). The higher the object stacks are, the bigger and more expensive the automated handling equipment. Due to the lack of flexibility in transporting and positioning the picker against the object holder, associated with the rigid catch of the object, most known solutions encounter picking errors, like dropping the object during transport or simultaneously engaging two objects.  
         [0005]     Automated grippers eliminate the need for a vertical traveling transporting arm and actuators (U.S. Pat. Nos. 5,797,639, 6,257,636, 4,253,695). However, existing solutions are either too complex or inappropriate for applications where high precision is needed in order to separate thin stacked objects, such as CD/DVD. A simpler automatic pickup device is needed, preferably able to grip the object from beneath in order to secure it during transport.  
         [0006]     Currently many CD/DVD processing equipment does not allow a horizontal disk to be vertically placed directly into the tray of their processing units, a part of the circular disk holder being masked by the front cover of the equipment ( FIG. 6A ). There haven&#39;t been any methods previously known for automatic loading/unloading disks into such equipment.  
       BRIEF SUMMARY OF THE INVENTION  
       [0007]     The present invention discloses a pickup device for gripping, holding and releasing similar objects, such as compact discs, able to alternately switch between object engaging/disengaging statuses by itself, using a previously known self contained switching mechanism, automatically triggered each time the device reaches an end-of-travel position to an object holder. There is a single external axial movement performed for both transporting the pickup device towards the object holder and engaging/disengaging the object, thus simplifying the automation equipment and decreasing its cost.  
         [0008]     The pickup device comprises a guiding element with a stopping shoulder enabling self adjustment to an optimal position when placed against the object. Unlike some other known automatic grippers (i.e. U.S. Pat. No. 6,257,636), the grippers are secured to the said guiding element in contact with the object and, when engaging the object, the grippers are actuated before the said guiding element starts moving. This feature enables gripping precision, important especially when working with stacked objects that have to be separated.  
         [0009]     A new solution for gripping the object is disclosed: pierced gripping blades housed inside the guiding element are penetrated by thin curved arms rigidly attached to an actuator, connected to the external transport means, axially moving with respect to the guiding element within a short travel range. The arms are axially moving together with the actuator and glide through the holes of the gripping blades, forcing the protrusive grippers to radially glide out their housing engaging the object or respectively retract inside the guiding element releasing the object, accordingly with the pickup device status. These features allow error free operation of the pickup device and a single external action performed for both axial transport of the pickup device and actuating the grippers. When appropriate, the grippers may glide under the object, supporting it from beneath. This way the object is secured during transport and the arms are relieved from tension, the burden being supported by the gripping blades.  
         [0010]     Unlike previously known automatic grippers, the pickup device disclosed herein is meant to use a regular switching mechanism like the ones used by retractable ball-point pens, rather than a customized, dedicated one. A simple two components mechanism is being used, like, for example, the one described in U.S. Pat. No. 5,997,204. Consequently the entire construction is simplified. One component of the switching mechanism is rigidly attached to the actuator so they axially move together when driven by the transport means. The second component of the switching mechanism is attached to the guiding element by a retaining pin and allowed to spin around the common axis, but not to move away axially.  
         [0011]     For applications where the objects are to be lifted, the hanging picker can be vertically ascended and descended using flexible means, like thread, wire, flexible ribbon or tape. This way there is no need neither for a vertical traveling supporting arm, nor for a frame or a vertical shaft for the picker to travel along. The object handling robot becomes very simple and small, allowing though long vertical travel for the picker, said large automated processing capacity.  
         [0012]     A wide variety of CD/DVD processing equipments could be automated by such a versatile robot placed above the said master equipment, where the disks are vertically stacked and delivered to/from retainers located under the surface supporting the robot and accessed from above. One possible embodiment is shown in  FIG. 7 . Depending on the amount of disks to be processed, the user can choose the number and the positions of the disk retainers to be used during each automated processing cycle. The invention discloses a simple, fast and effective procedure for positioning the disk retainers, where the robot delivers to the selected location a positioning device and the user transfer the retainer over the positioning device and takes the device away ( FIG. 9A -C).  
         [0013]     Currently many CD/DVD processing equipment does not allow a horizontal disk to be vertically placed directly into the trays of their processing units, a part of the circular disk holder area being masked by the front cover of the equipment ( FIG. 6A ). A method and a corresponding embodiment are disclosed where the disk is inclined toward the processing equipment when lifted from its horizontal tray by the vertically moving pickup device, and glides into the tray from its inclined position to a final horizontal position when vertically delivered by the picking device into the tray, allowing automatic loading/unloading disks into such processing equipment ( FIG. 5 ,  FIG. 6A ,B). 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1A -C are perspective views of prior art switching mechanism in different statuses  
         [0015]      FIG. 2  is a cross-section view of the pickup device placed against the stacked objects  
         [0016]      FIG. 3  is a cross-section view of the pickup device in object-disengaged status  
         [0017]      FIG. 4A -B are cross-section views of the guiding element along the gripper&#39;s housing plane, two embodiments  
         [0018]      FIG. 5  is a cross-section view of the pickup device in object-engaged status, disk inclined embodiment  
         [0019]      FIG. 6A -B are schematically views of a processing unit with a tray having partially masked disk holding area and of the trajectory of an inclined disk being vertically transported to/from such a tray  
         [0020]      FIG. 7  is a perspective view of one possible embodiment of a robot  
         [0021]      FIG. 8  is a cross-section view of the pickup device in object-engaged status, horizontal disk embodiment  
         [0022]      FIG. 9A -C show the sequences for positioning a stack retainer: the robot delivers the positioning device to the selected location, the user transfer the retainer over the positioning device and takes the device away.  
     
    
     DESCRIPTION  
       [0023]     Many technologies require objects to be automatically and repetitively transported to/from specified locations in order to be processed. The pickup device has to alternately pick-up the object from one source location and respectively to release it at the destination location. The present invention discloses a pickup device for gripping, holding and releasing similar objects, such as compact discs, that does not require any additional external actuation for gripping the object, being able to alternately switch between object engaging/disengaging statuses by itself, by means of a self contained switching mechanism, automatically triggered each time the device reaches an end-of-travel position to an object holder. For ease of the description the various handled objects will be referred herein as “disks”. For simplicity, in the preferred embodiment described, the object holders are horizontal, the disks are vertically stacked and the pickup device moves vertically along the axis of the object holder in order to engage or disengage a disk, being subsequently transported above a different location.  
         [0024]     Many types of previously known switching mechanisms can be used, like the ones used by retractable ball-point pens or some push-button electric switches. For simplicity, the pickup device disclosed herein uses a mechanism like the one described in U.S. Pat. No. 5,997,204. Its functioning is only briefly described here, in order to ease further description of the pickup device itself. The switching mechanism ( FIG. 1A -C) comprises two parts: a cylindrical pin  2  having two pairs of diametrically opposed protruding ribs  3  and a cylindrical ring  1  comprising grooves and saw-teething on its inner surface (not shown). Considering the mechanism positioned vertically and pin  2  allowed to rotate, when the ring  1  is axially moved upwards along the central pin  2 , the ribs glide on the inclined surface of the teeth, the pin rotates and the ring stops like shown in  FIG. 1A , when the upper ribs  3  reach the deepest points of the current saw-teeth grooves, so the ring grips the pin. This position will determine a “disk engaged status” within the further description of the pickup device. Afterwards, when the ring  1  is axially moved downwards to the opposite direction, the other pair of ribs glides on the saw-teething on the other side of the ring, the pin rotates and the ring stops as shown in  FIG. 1B , when the ribs reach the deepest points of the current saw-teeth. We will refer it as a “switching position”. When subsequently the ring is moved upwards again, the process repeats, but the ring will grip the pin and stop after a shorter vertical travel, as shown in  FIG. 1C , due to the different shape of the corresponding saw-teeth. This position will determine a “disk disengaged status” within the further description of the pickup device. Each reaching of a “switching position”, will determine subsequent change of status for the picking device: always a “disk engaged status” will be followed by a “disk disengaged status” and vice versa.  
         [0025]     A guiding element  6  having a stopping shoulder  7  enable the picking device to self adjust its position to an optimum when placed against the object, like shown in  FIG. 2 . A central pin  5  connects the guiding element with the pin  2 , component of the switching mechanism, allowing pin  2  to spin around the common central axis.  
         [0026]     The actuator  4  attached to the external axial movement means  12 , by which the entire pickup device is transported, comprises a central cylindrical bore that houses the ring  1 , component of the switching mechanism. The ring  1  is rigidly attached to the actuator  4 .  
         [0027]     Each time the guiding element  6  stops on an object holder, the actuator  4  continues its axial movement until eventually gets closest to the guiding element, when the mechanism reaches its switching position. When the transport means  12  pulls  4  away from  6 , the distance the two elements can get apart, before element  6  starts moving along with  4 , depends on the current status of the switching mechanism and alternates between a short and a long travel. This feature allows the picking device to alternate between object-engaging and object-disengaging statuses, the gripping means being actuated by the element  4  moving with respect to  6 . Unlike some other known automatic grippers (i.e. U.S. Pat. No. 6,257,636), the grippers are secured to the said guiding element in contact with the object and, when engaging the object, the grippers are actuated before the said guiding element starts moving. This feature enables gripping precision, important especially when working with stacked objects that have to be separated.  
         [0028]     For the preferred embodiments described herein, the axial distance between the stopping shoulder  7  and the sharp edges of the gripping blades  9  housed inside the recess  16  is slightly bigger than the thickness of the disk  15 , allowing the protruding blades  9  to grasp the disk from beneath when actuated.  
         [0029]     The gripping blades  9  comprise holes  10  for the thin curved arms  8 , rigidly attached to the element  4 , to cross through. The guiding element  6  has thin radial ditches  11  allowing the arms  8  to travel freely when the element  4  is axially moving against the guiding element. An optional dust-protective frame  14  may be rigidly attached to the guiding element  6 , provided that it allows room for the element  4  to move axially with respect to the guiding element within its entire travel range. The optional frame  14  should comprise a hole  13  on its top, opposite to the guiding element, for the transport means  12  to cross through.  
         [0030]     When the element  4  is axially pulled away from the guiding element by  12 , the arms  8  glide along the ditches  11  and through the holes  10  of the pierced blades  9  and, if the switching mechanism allows element  4  to rise enough, namely the pickup mechanism is in “disk engaged status”, they push the grippers  9  to glide out their housing  16 , then the guiding element  6  starts moving together with element  4 , that is the entire pickup device  21  is being moved by  12 .  
         [0031]     Suppose the picking device placed against a stack of disks as shown in  FIG. 2 , with the shoulder  7  laying on the top disk. The element  4  is closest to the guiding element  6  and the arms  8  keep the gripping blades  9  completely retracted inside their recess  16 . The mechanism is in “switching position”, like in  FIG. 1B . Furthermore, suppose the picking device was in “disk disengaging status” when placed against the stack, so we expect it to engage the disk next time when lifted from the stack. When the transport means  12  axially pulls element  4  away from the guiding element  6  resting on the disk beneath, the arms  8  glide through the holes  10  of the pierced blades  9  and push them to glide out of the guiding element, their sharp edges protruding under the first disk in stack. Then the guiding element  6  starts moving together with the element  4 , namely the entire pickup device  21  is lifted by  12 , carrying away the disk  15  so engaged, as shown in  FIG. 5 . The section views in  FIG. 4A  and  FIG. 4B  show the radial movement of the blades in two possible embodiments, with a single gripping blade and respectively with more gripping blades.  FIG. 8  shows such a multiple gripping blades embodiment of the pickup device in “disk engaged status”, where the disk keeps its horizontal position during transport.  
         [0032]     Suppose now the disk so engaged is transported to be released to a new location. The transport means  12  vertically lowers the pickup device on location and, when the disk reaches the holder, the guiding element  6 , with its shoulder  7  laying on the disk, stops. The actuator  4  continues its movement, approaching the guiding element. The arms  8  glide through the holes  10  of the pierced blades  9  forcing them to retract completely inside the guiding element  6 . The movement stops when the element  4  reaches its lowest position, closest to the guiding element, when the pickup device is in “switching position”, as shown in  FIG. 2 .  
         [0033]     Next lift will find the pickup device in “disk disengaged status”, so the mechanism will determine the element  4  to grip the guiding element  6  after a short travel, before the arms  8  start pushing the grippers  9  out, so the gripping blades will not protrude out of the guiding element, therefore the pickup device  21 , lifted by  12 , will leave unloaded as shown in  FIG. 3  and the disk will remain in its holder.  
         [0034]     The cycle is permanently repeated, the pickup device alternating between disk engaging/disk disengaging statuses each time it reaches the down-end-of-travel position to an object holder.  
         [0035]     In the particular embodiment described, where the pickup device moves vertically towards the disk holder in order to engage or disengage a disk, the device can hang gravitationally, being ascended/descended using flexible means  12  like thread, wire, flexible ribbon or tape. Such a solution dramatically simplifies the automation equipment, since there is no need neither for a vertical traveling arm, nor for a frame or a vertical shaft for the picker to travel along. Moreover, long vertical travel for the pickup device, namely large capacity for the disk handling robot can be achieved, even though the robot itself is small and basically flat, the transporting flexible wire  12  being simply coiled on a reel inside the robot and guided out on a pulley attached to the horizontally moving part of the robot. The pickup device  21  is lifted up to its highest position where a basically cylindrical holder under the pulley houses it, keeping its vertical position and preventing it from waggling during the horizontal movement from a disk holder to another. The robot should be positioned in such a way that it can access from above the disk holders, namely the trays of the disk processing equipment and the stacks for processed/unprocessed disks.  
         [0036]     A possible embodiment is shown in  FIG. 7 , where the robot  22  is placed over a disk processing master equipment  20 , comprising processing units  25 , provided with trays  18 . Requests for disk changing are correspondingly sent to the robot by the master equipment whenever needed, for example via RS232 interface. Disk retainers  24  for the disk stacks are placed on the table, around the master equipment served by the robot. The robot may comprise a keyboard  23  for interfacing with the human operator. Depending on the number of disks to be processed, the user can choose the number and the positions of the disk retainers  24  to be used during each automated processing cycle. Once the configuration selected, the user have to place the disk retainers on the table, precisely at the locations further accessed by the robot. The following procedure will be reiterated for each disk retainer to be positioned: 
        the user selects the desired location with the keyboard  23  and places on the tray  18  a positioning device  27 , basically cylindrical shaped and hollowed, comprising a top cover with a central hole similar with a regular disk, so the robot can handle it like an ordinary disk     the robot picks up, transports and releases the positioning device  27  on the table to the selected location, then the pickup device  21  ascends into its housing ( FIG. 9A )     the user transfers over the positioning device  27  so located a supporting device  26 , basically ring shaped, comprising an opening that fit the outer size of the positioning device so it surrounds the positioning device and attaches to the table, for example by self sticking means ( FIG. 9B )     the user takes away the positioning device ( FIG. 9C ) and places over the supporting device so fixed on the table the disk retainer whose bottom shape mates the shape of the supportive device in such a way that the retainer cannot move horizontally. For CDs or DVDs, the original plastic cylindrical covers of regular commercial disk spindles packages can be used as disk retainers.        
 
         [0041]     Currently many CD/DVD processing equipment does not allow a horizontal disk to be vertically placed directly into the trays  18  of their processing units, a part of the circular disk holder area being masked by the front cover  19  of the equipment ( FIG. 6A ). If the disk is inclined towards the processing equipment during vertical travel along the central axis of the circular disk holder of such a tray, it may be transported to/from and delivered into the tray without interfering with the said front cover masking  19 , as shown in  FIG. 6B . The embodiment of the pickup device shown in  FIG. 5  can deliver a disk to/from such a tray as follows: the gripping blade hooks the disk asymmetrically, from the part opposite to the equipment. When lifted, the disk inclines towards the processing equipment up to the desired angle, about 45 degrees, when it reaches the stopping shoulder  17  on the guiding element. The shape of the guiding element itself is important since it has to allow the disk to rotate freely, preventing it from falling, too. The transport means  12  must not allow the pickup device to spin around its axis, so the disk maintains its inclined position towards the equipment during its vertical travel. When the disk is vertically descended in order to be released into the tray, its lower edge glides into the tray and the disk rotates from its inclined position to the final horizontal position, as shown in  FIG. 6B .