Patent Publication Number: US-11383393-B2

Title: Mechanism for exchanging concentric suction cups

Description:
BACKGROUND 
     The present invention is related to robotics, and more particularly to a robotic mechanism for lifting objects using suction cups. 
     Automation for lifting objects, such as those of the type that employ suction cups for lifting objects under a vacuum, is used in many facilities. The lifting capacity of a suction cup is related to vacuum pressure and effective area of the suction cup. In facilities in which the same size objects are repeatably engaged by suction cups, the suction cup, end effector, and other components may be designed according to straightforward principles. 
     In facilities in which objects of different sizes and weights are lifted, smaller sized suction cups may be incapable of lifting larger or heavier objects. And larger sized suction cups may have a diameter too large to seal around smaller objects. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment mechanism for exchanging and deploying suction cups, illustrating a small suction cup deployed and a large suction cup spaced apart from the small suction cup and attached to a housing by magnets; 
         FIG. 2  is a perspective view of the mechanism of  FIG. 1 , illustrating the large suction cup in a deployed position; 
         FIG. 3  is a perspective, cross sectional view of the mechanism of  FIG. 2 ; 
         FIG. 4  is a cross sectional view of an enlarged portion of the mechanism shown in FIG. 
         FIG. 5  is a perspective view of a second embodiment mechanism for exchanging and deploying suction cups, illustrating a large suction cup attached to a housing by a twist lock, with the components shown transparent; 
         FIG. 6  is an enlarged cross sectional view of a portion of the assembly of  FIG. 5   
         FIG. 7  is an exploded view of the some components of the embodiment of  FIG. 5 , including the outer suction cup, inner tube, and ball detents; 
         FIG. 8  is a perspective view of the outer suction cup detached from the assembly; 
         FIG. 9  is a perspective view of a third embodiment mechanism for exchanging and deploying suction cups, illustrating a large suction cup attached to the inner tube by a twist lock, with the components shown transparent; 
         FIG. 10  is a top perspective view of a fourth embodiment mechanism for exchanging and deploying suction cups, with the inner suction cup removed for clarity; 
         FIG. 11  is a bottom perspective view of the embodiment of  FIG. 10 ; 
         FIG. 12  is a cross sectional view of the embodiment of  FIG. 10  showing the assembly in a position ready to deploy the outer suction cup; 
         FIG. 13  is the assembly of  FIG. 13  with the outer suction cup deployed; 
         FIG. 14  is the assembly of  FIG. 10  showing the assembly in a position ready to deploy the inner suction cup; and 
         FIG. 15  is the assembly of  FIG. 13  with the inner suction cup deployed. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     In general, a mechanism for exchanging concentric suction cups uses a single linear telescoping actuator to exchange and deploy two (or more) different sizes of suction cups. In this regard, the mechanisms allow a larger outer suction cup to attach to a telescoping mechanism to be then used to pick an object, such as an item in a fulfillment center, and also allow the option to deploy a smaller diameter suction cup to engage and pick the object. The large suction cup can be used for relatively large objects and the small suction cup may be used for relatively small objects. 
     The mechanisms disclosed herein preferably secure the outer suction cup to a telescoping mechanism or, alternatively, to a housing which is retained at a fixed distance from the housing mounting. The telescoping mechanism also has a fixed smaller suction cup which is used to pick items when then larger suction cup is secured to the outside housing. The housing may be mounted to an automated system, such as without limitation an end effector or any type, a robotic arm, a gantry, a mounting that is fixed in space, or any other structure. 
       FIGS. 1 through 4  illustrate a first embodiment of an assembly or mechanism  110  to exchange two suction cups, such that either a large suction cup or small suction cup can be deployed as needed. Assembly  110  includes a tubular housing  120  having a mounting end  122  at its proximal end, which is opposite the distal end at which the suction cups are located. Mounting end  122  is adapted for attaching preferably to an end effector (not shown) or to any other structure, according to the particular parameters of the application. An inner telescoping tube assembly  130  includes at least one inner tube  132 . In the embodiment shown in  FIG. 3 , inner tube  132  is the distal one of telescoping tubes, which also include an intermediate tube  134  that is concentric with and outboard of inner telescoping tube  132 , and a proximal tube  136  that is concentric with and outboard of intermediate tube  134 . In the embodiment of the figures, proximal tube  136  is fixed relative to housing  120 , and may house the actuator(s) described below. 
     Preferably, a linear actuator, shown schematically by reference numeral  190  in  FIG. 3 , has a proximal end that is affixed relative to housing  120  and a distal end that is operatively coupled to inner tube  132  such that actuator  190  can extend and then retract the suction cups at the distal end of inner tube  132 . Actuator  190  can be a pneumatic actuator (preferred), a hydraulic actuator, a mechanical actuator such as an ACME screw, or any other mechanism capable of extension and retraction upon being energized, without limitation. 
     Assembly  110  includes an outer suction cup  140  and an inner suction cup  150 . Inner suction cup  150  has a smaller diameter than outer suction cup  140  and is nestable or retractable within outer suction cup  140 . In the embodiment shown in the figures, outer suction cup  140  is cup-like and includes a resilient contact ring  142 , a cylindrical or somewhat conical sidewall  144 , an end wall  146 , and a ring  148  ( FIG. 4 ). Inner suction cup  150  is preferably affixed to a distal end of distal tube  132 , such as by screw threads or like means. Inner suction cup  150  includes a contact ring  152 , a bellows-like sidewall  154 , and threads  156  or other attachment means. 
     Assembly  110  has a pair of interlocks  160  and  170  to exchange or control the suction cups by coupling or engaging outer suction cup  140  with the distal end of inner tube  132  and, alternatively, with housing  120 . In this regard, the phrase “engaged with the housing” as used herein refers to connecting the outer suction cup  140  to a fixed structure. Moreover, the term “housing” is intended to be broadly interpreted to refer to fixed structure relative to an end effector or the like. 
     An interlock  160  between outer suction cup  140  and distal inner tube  132  preferably includes ball detents. As illustrated in  FIG. 4 , each ball detent interlock  160  includes a housing  162  that is threaded into holes in outer cup ring  148 , a coil spring  164 , a ball  166 , and a recess  168  in the outboard surface of inner tube  132 . Preferably, several (such as six or eight) detents are located about the circumference of outer suction cup  140 . Spring  164  is compressed such that it applies an inward, radial force on ball  166 , and in that way presses ball  166  into recess  168 . Preferably, recess  168  is a partial sphere to match the surface of ball  166 . 
     An interlock  170  between outer suction cup  140  and housing  120  preferably includes opposing electromagnets including magnets  171  on suction cup  140  and opposing magnets  172  on housing  120 . As illustrated in the figures, housing magnets  172  are located on an outer periphery of housing  120 ; outer suction cup magnets  171  are on a rear side of end wall  146  of outer suction cup  140 . Because the electromagnets  171 , 172  can be energized to engage or disengage suction cup  140  from housing  120 , the interlock  170  is referred to herein as an active interlock. It is understood that the active interlock is not limited to electronic actuated magnets, but rather encompasses any type of electric, electro-mechanical, or mechanical interlock, without limitation. 
       FIG. 1  illustrates magnets  171  engaged with magnets  172  to retain outer suction cup  140  with housing  120  while tube  132  is extended.  FIG. 2  illustrates magnets  171  disengaged with magnets  172 , and ball detent  160  of outer suction cup  140  engaged with recess  168  of inner tube  132 . In operation, upon assembly  110  being positioned relative to an object, a controller (not shown) determines to deploy either the larger outer suction cup  140  or the smaller inner suction cup  150 . The controller preferably bases the decision based on information about the object already known to the control system, according to conventional principles that will be understood by persons familiar with automated lifting of objects, such as in a fulfillment center. 
     Alternatively, magnets  171  and  172  may be conventional magnets that are not electronically actuated such that proximity, as when outer suction cup  140  is located in contact with housing  120 , creates an attractive force that retains outer suction cup  140  against housing  120 . The operation of the mechanism for exchanging the suction cups employing a pair of passive interlocks is explained more fully below. 
     If the object is determined by a control system to be small such that inner suction cup  150  is desired to be deployed, electromagnetic interlock  170  engages to retain outer suction cup  140  to housing  120 . Because the force required to overcome ball detents  160  is less than the force required to overcome magnet interlock  170 , balls  166  release from recesses  168  when actuator  190  extends from its fully retracted position. Thus, inner tube  132  and telescoping tube  134  extend distally from fixed tube  136  and housing  120  while outer suction cup  140  remains affixed to housing  120  to deploy only inner suction cup  150 , which is then engaged with an object. Vacuum applied through tubes  132 ,  134 ,  136 , which is at least partially sealed by suction cup ring  152 , enables lifting of the object by engagement with the suction cup. Control of inner suction cup  150  and telescoping tubes  132 ,  134  preferably are by conventional controlling means, as will be understood by persons familiar with employing automated suction cups for lifting objects. 
     If the object is determined by a control system to be large such that outer suction cup  140  is desired to be deployed, electromagnetic interlock  170  disengages to free outer suction cup  140  from housing  120 . Ball detents  160  retain outer suction cup  140  with the distal end of tube  132  to carry outer suction cup  140  when actuator  190  extends from its fully retracted position. Thus, outer suction cup  140 , with inner tube  132  and telescoping tube  134 , extend distally from fixed tube  136  to deploy outer suction cup  140 , which is then engaged with an object. As illustrated in the figures, inner suction cup  150  also is deployed when outer suction cup  140  is deployed. Because inner suction cup  150  either recessed relative to (or flush with) outer suction cup  140 , vacuum applied through tubes  132 ,  134 ,  136 , which is at least partially sealed by suction cup ring  142 , enables lifting of the object by engagement with the suction cup  140 . In this regard, vacuum may be applied via only outer cup  140  or may be applied via both outer cup  140  and inner cup  150  when outer cup  140  is deployed. Where irregularly shaped objects are expected to be engaged, it is preferred that inner suction cup  150  be recessed relative to contact ring  142 . Control of inner suction cup  140  and telescoping tubes  132 ,  134  preferably are by conventional controlling means, as will be understood by persons familiar with employing automated suction cups for lifting objects. 
       FIG. 5  illustrates a second embodiment assembly  210  that includes a tubular housing  220  having a mounting end  222  at its proximal end that is opposite from the suction cups and that is adapted for mounting preferably to an end effector (not shown) or to any other structure, according to the particular parameters of the application. An inner telescoping tube assembly  230  includes at least one inner tube  232 . In the embodiment shown in  FIG. 5 , inner tube  232  is the distal most telescoping tube. Additional telescoping tubes, as described for first embodiment assembly  110  may be employed. In the embodiment of the figures, a proximal tube  236  is fixed relative to housing  220 . 
     Preferably, a linear actuator, shown schematically by reference numeral  290  in  FIG. 5 , has a proximal end that is affixed relative to housing  220  and a distal end that is operatively coupled to inner tube  232  such that actuator  290  can extend and then retract the suction cups at the distal end of inner tube  232 . Actuator  290  can be as described for first embodiment actuator  190 . Preferably, assembly  210  also includes a rotary actuator  292 , which is illustrated schematically along with linear actuator  290  by a dashed line in  FIG. 5  and described more fully below. 
     Assembly  210  includes an outer suction cup  240  and an inner suction cup  250 . Inner suction cup  250  has a smaller diameter than outer suction cup  240  and is nestable or retractable within outer suction cup  240 . In the embodiment shown in the figures, outer suction cup  240  is cup-like and includes a resilient contact ring  242 , a cylindrical or somewhat conical sidewall  244 , an end wall  246 , and a ring  248  ( FIG. 4 ). Inner suction cup  250  preferably is mounted to a distal end of distal tube  232 , such as by screw threads or like means. Inner suction cup  250  includes a contact ring  252 , a bellows-like sidewall  254 , and threads  256  or other attachment means. 
     Assembly  210  has a pair of interlocks  260  and  270  to exchange or control the suction cups by coupling or engaging outer suction cup  240  with the distal end of inner tube  232  and, alternatively, with housing  220 . An interlock  260  between outer suction cup  240  and housing  220  preferably includes ball detents. As illustrated in  FIGS. 6 and 8 , each ball detent interlock  260  includes a housing  262  that is threaded into holes in outer cup ring  248 , a coil spring  264 , a ball  266 , and a recess  268  in the inboard surface of outer tube  220 . Preferably, several (eight as shown in the figures) detents are located about the circumference of outer suction cup  240 . Spring  264  is compressed such that it applies an outward, radial force on ball  266 , and in that way presses ball  266  into recess  268 . Preferably, recess  268  is a partial sphere to match the surface of ball  266 . 
     An interlock  270 , referred to as a twist lock, between outer suction cup  240  and inner tube  232  preferably includes lugs or tabs  272  extending radially outwardly from an outboard surface of inner tube  232 , as best shown in  FIG. 7 . Tabs  272  are configured engage or ride in corresponding spiral or inclined threads or grooves  274  formed in ring  242  of outer suction cup  240 , as best shown in  FIG. 8 . Thus, rotary actuator  292  may rotate inner tube  232  when outer suction cup  240  is proximate to housing  220  such that outer suction cup  240  is drawn upwardly (that it toward housing  220 ) by the screw action of tabs  272  in grooves  274 . When twist lock  270  is engaged, outer suction cup  240  is coupled to inner tube  232 . When twist lock  270  is disengaged (that is, tabs  272  are not within grooves  274 ), outer suction cup  240  remains coupled to housing  220  by the action of ball detent interlock  260 , even while tube  232  is extended. 
     Thus, in operation, upon assembly  210  being positioned relative to an object, a controller (not shown) determines to deploy either the larger outer suction cup  240  or the smaller inner suction cup  250 . The controller preferably bases the decision based on information about the object already known to the control system, according to conventional principles that will be understood by persons familiar with automated lifting of objects, such as in a fulfillment center. 
     If the object is determined by a control system to be small such that inner suction cup  250  is desired to be deployed to engage the object, rotary actuator  292  rotates tube  232  to thread tabs  250  out of engagement with grooves  254  (counter-clockwise in the embodiment shown in the figures when viewed from above). In this regard, outer suction cup  240  is restrained from rotation by detents  260  (or other means) during the actuation of rotary actuator  292 . Balls  266  are engaged into recesses  268  to retain outer suction cup  240  with housing  220  while linear actuator  290  extends from its fully retracted position. Thus, inner tube  232  extends distally from housing  220  to deploy inner suction cup  250 , which is then engaged with an object. Vacuum and controls are as described for first embodiment assembly  110 . 
     If the object is determined by a control system to be large such that outer suction cup  240  is desired to be deployed to engage the object, rotary actuator  292  rotates tube  232  to thread tabs  250  into engagement with grooves  254  (clockwise in the embodiment shown in the figures when viewed from above). Upon inner tube  232  extension by linear actuator  290 , outer suction cup  240  is deployed, as it is threaded onto tube  232  and released from ball detent interlock  260 . Vacuum and controls are as described for first embodiment assembly  110   
       FIG. 9  illustrates a third embodiment assembly  310  that includes a tubular housing  320  having a mounting end  322  at its proximal end that is opposite from the suction cups and that is adapted for mounting preferably to an end effector (not shown) or to any other structure, according to the particular parameters of the application. An inner telescoping tube assembly  330  includes at least one inner tube  332 . In the embodiment shown in  FIG. 9 , inner tube  332  is the distal most telescoping tube. Preferably, a linear actuator  390 , rotary actuator  393 , outer suction cup  340 , inner suction cup  350 , and twist interlock  370  (including tabs  372  and grooves  374 ) are as described for second embodiment linear actuator  290 , rotary actuator  293 , outer suction cup  240 , inner suction cup  250 , and twist interlock  270  (including tabs  272  and grooves  274 ). 
     Assembly  310  has an interlock  360  between outer suction cup  340  and housing  320 . Interlock  360  preferably includes opposing electromagnets, including magnets  361  on suction cup  340  and opposing magnets  362  on housing  320 . As illustrated in the  FIG. 9 , housing magnets  362  are located on an outer periphery of housing  320 ; outer suction cup magnets  361  are on a rear or proximal side of the end wall outer suction cup  340 . Because the electromagnets  361 ,  362  can be energized to engage or disengage suction cup  340  from housing  320  (as described for first embodiment  110 ), the interlock  360  is referred to herein as an active interlock. It is understood that the active interlock is not limited to electronic actuated magnets, but rather encompasses any type of electric, electro-mechanical, or mechanical interlock, without limitation. 
     In operation, upon assembly  310  being positioned relative to an object, a controller (not shown) determines to deploy either the larger outer suction cup  340  or the smaller inner suction cup  350 . The controller preferably bases the decision based on information about the object already known to the control system, according to conventional principles that will be understood by persons familiar with automated lifting of objects, such as in a fulfillment center. 
     If the object is determined by the control system to be small such that inner suction cup  350  is desired to be deployed to engage the object, rotary actuator  392  rotates tube  332  to thread tabs  350  out of engagement with grooves  374 . In this regard, outer suction cup  340  is restrained from rotation by the action of the magnets  370  while magnets  371 ,  372  are engaged to retain outer suction cup  340  with housing  320 . As actuator  390  extends from its fully retracted position, inner tube  332  extends distally from housing  320  to deploy inner suction cup  350 , which is then engaged with an object. Vacuum and controls are as described for second embodiment assembly  210 . 
     If the object is determined by the control system to be large such that outer suction cup  340  is desired to be deployed, twist lock  370  couples outer suction cup  340  to inner tube  332  by the rotary motion of actuator  392  (in an opposite rotational direction from the disengaging direction). Magnets  371 ,  372  are then de-energized such that the extension of tube  332  by linear actuator  390  extends outer suction cup  340  relative to housing  320 . Thus, outer suction cup  340 , with inner tube  332 , extends distally from housing  320  to deploy outer suction cup  340 , which is then engaged with an object. Inner suction cup  350  may be recessed relative to outer suction cup  340  as described for second embodiment  210 . 
     Alternatively, magnets  371  and  372  may be conventional magnets that are not electronically actuated such that proximity, as when outer suction cup  340  is located in contact with housing  320 , creates an attractive force that retains outer suction cup  340  against housing  340 . In this regard, the assembly would have a pair of passive interlocks. The attractive force is broken when the outer suction cup  340  is engaged by the tab and groove structure of interlock  360  and the attractive force is re-engaged and the twist lock  360  is disengaged to enable inner tube  332  to deploy, as needed. 
       FIGS. 10 through 15  illustrate a fourth embodiment of an assembly or mechanism  410  to exchange two suction cups, such that either a large suction cup or small suction cup can be deployed as needed. Assembly  440  includes a tubular housing  420  having a mounting end (not shown in the figures) at its proximal end that is opposite from the suction cups and that is adapted for mounting preferably to an end effector (not shown) or to any other structure, according to the particular parameters of the application. In the embodiment shown in the figures, an inner tube  432  is the distal most telescoping tube and an intermediate tube  434  is concentric with and outboard of inner telescoping tube  432 , and concentric with and inboard of outer housing  420 . 
     Preferably, a linear actuator, shown schematically by reference numeral  490  in  FIG. 10 , has a proximal end that is affixed relative to housing  420  and a distal end that is operatively coupled to inner tube  432  such that actuator  490  can extend and then retract the suction cups at the distal end of inner tube  432 . A second actuator, illustrated schematically by reference numeral  492  in  FIG. 10 , has a fixed proximal end and it operatively coupled to housing  420  such that actuator  492  can extend and then retract housing  420  relative to inner tube  432 , as explained more fully below. Actuator  490  and/or actuator  492  can be a pneumatic actuator (preferred), a hydraulic actuator, a mechanical actuator such as an ACME screw, or any other mechanism capable of extension and retraction upon being energized, without limitation. Assembly  410  includes an outer suction cup  440  and an inner suction cup  450 . Inner suction cup  450  has a smaller diameter than outer suction cup  440  and is nestable or retractable within outer suction cup  440 . In the embodiment shown in the figures, outer suction cup  440  is tapered and includes a resilient contact ring  442 , a conical sidewall  444 , an end wall  446 , and a ring  448  ( FIG. 4 ) that is threaded onto intermediate tube  434 . Inner suction cup  450 , which is omitted from the figures for clarity, is preferably mounted to a distal end of distal tube  432 , such as by screw threads or like means. Inner suction cup  450  can be as described for first inner suction cup  150 . 
     A spring  494  around inner tube  432  has a lower end that acts on an upper surface of outer suction cup  440  and an upper end that acts on a housing  496 . 
     Assembly  410  has a pair of passive interlocks  160  and  170  to exchange or control the suction cups by coupling or engaging outer suction cup  440  with the distal end of inner tube  432  and, alternatively, with housing  420 . Interlocks  160  and  170  are provided by a single ball detent that employs a recess in the outboard surface of inner tube  432  and a recess in an inboard surface of housing  420 . 
     Interlock  460  between intermediate tube  434  and distal inner tube  432  preferably includes a ball  466  and a recess ring  468  in the outboard surface of inner tube  432 . Preferably, several (such as six or eight) balls  466  are located about the circumference of inner tube  432 . Interlock  470  between intermediate tube  434  and housing  420  preferably includes ball  466  and a recess ring  478  in the inboard surface of housing  420 . In the embodiment shown, the force required to overcome inner interlock  460  is greater than the force required to overcome outer interlock  470 . 
     As illustrated in  FIG. 12 , ball  466  is engaged in with interlock  460  to retain intermediate tube  434  with inner tube  432 .  FIG. 12  illustrates the outer suction cup  140  partially deployed by actuator  490  as housing  420  is held in place such that ball detent  170  is disengaged and ball detent  460  is engaged (that is, ball  466  is in groove  468  and out of groove  478 ). As best shown in  FIG. 13 , as outer suction cup  140  is deployed, the spring force of spring  494  against housing  496  keeps housing  496  in position over ball  466  to retain ball  466 . 
     To begin the deployment of inner tube  432 , actuator  492  drives outer tube  420  down relative to inner tube  432  and intermediate tube  434  until recess ring  478  engages ball  466 , which moves housing  494  out of engagement with ball  466 . Then, housing  420  is held in place while actuator  490  extends inner tube  432  to extend inner suction cup  550 , as illustrated in  FIGS. 14 and 15 . 
     If the object is determined by a control system to be small such that inner suction cup  450  is desired to be deployed, second actuator  492  moves housing  420  relative to intermediate tube  434  to engage outer detent  470  (that is, such that ball  466  is in housing ring  478 ) to retain outer suction cup  440  with housing  420 . Then linear actuator  490  applies a downward force to extend inner tube  432  and inner suction cup  450  while outer suction cup  440  is retained by outer interlock  470  and ball  466  is retained by housing  496 . In this regard, when inner tube  432  and housing  420  are positioned such that rings  468  and  478  are aligned and ball  466  can simultaneously reside at least partially in each one of rings  468  and  478  simultaneously, inner tube  432  is free or held by a very small detent force of interlock  470  because ball  466  can move outwardly slightly into housing ring  478 , thus facilitating release and extension of inner tube  432 . 
     If the object is determined by a control system to be large such that outer suction cup  440  is desired to be deployed, one or both actuators move housing  420  upwardly relative to intermediate tube  434  (or intermediate tube  434  downward relative to housing  420 ) to disengage ball  466  from ring  478 , such as (without limitation) by aligning rings  468  and  478 , then moving housing  420  relatively upwardly to disengage outer interlock  470  (that is, ball  466  is retained in inner tube ring  468  and free from outer tube ring  478 , as illustrated in  FIG. 12 ). Housing  496  preferably is cylindrical and dimensioned to retain ball  466  in inner tube ring  468 . Because inner ball detent  460  retains inner tube  432  with intermediate tube  434 , the extension of inner tube  432  by the action of linear actuator  490  deploys outer vacuum tube  450 . Vacuum and control is as described for first embodiment assembly  110 . 
     Throughout the description, objects are referred to as small and large. It is not intended that the disclosure is limited to any size objects. Rather, the terms “small” and “large” are used only for relative comparison of the objects, and when applicable the suction cup size or diameter. Accordingly, a “small” object may be objectively big, or a “large” object may be objectively small, so long as the relative relationship between the sizes is consistent. Further, the invention is illustrated employing a pair of suction cups, but the present invention is not limited to two suction cups, as the principles of the present invention may be employed with interlocks to exchange more than two suction cups. 
     The particular embodiments disclosed are used to illustrate aspects of the present invention. It is not intended that the present invention be limited to the particular structure and/or function of the embodiments. Rather, it is intended that structure and function of any one of the embodiments can be shared with other ones of the embodiments disclosed. Further, it is intended that the scope of the claims be the measure of the invention, as the disclosed structure and function are intended merely to be specific examples of the general principles, as claimed.