Abstract:
A gripper assembly including at least one gripper jaw and an actuator operative for moving the at least one gripper jaw. A support is fixed relative to the actuator for supporting the at least one gripper jaw. A stop member is removably affixable between the at least one gripper jaw and the support for limiting movement of the at least one gripper jaw.

Description:
REFERENCE TO RELATED APPLICATIONS 
     The application claims priority to U.S. Provisional Application No. 60/904,978 which was filed on Mar. 5, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention generally relates to automated handling equipment. More particularly, this invention relates to an actuated gripper device having adjustable bumper stops for limiting the degree to which gripper jaws open. 
     Automated handling equipment is typically employed in industrial settings for transferring work pieces between work stations. Typically, the equipment includes a gripper that clamps the work pieces while moving them between the stations. Conventional grippers include an actuator that moves one or more gripper jaws between open and closed jaw positions. In some examples, the grippers move within tight spaces in the work stations. In this respect, the degree to which the gripper jaws open must be controlled in order to avoid contact with the surrounding work stations. 
     Typically, the automated handling equipment is adapted for a particular work station. When a different product is produced at the work station, or when the automated handling equipment is used at a different work station, it may be desirable to change the degree to which the jaws open to suit the particular work station or to suit a particular work piece size. In this regard, the grippers must be adjustable. Accordingly, there is a need for a gripper having an adjustable bumper stop for varying a degree to which a gripper jaw opens that can be easily adjusted without having to significantly disassemble the gripper. This invention addresses this need and provides enhanced capabilities while avoiding the shortcomings and drawbacks of the prior art. 
     SUMMARY OF THE INVENTION 
     An example gripper assembly includes at least one gripper jaw and an actuator that is operative for moving the at least one gripper jaw. A support is fixed relative to the actuator for supporting the at least one gripper jaw. A stop member is removably affixable between the at least one gripper jaw and the support for limiting movement of the at least one gripper jaw. 
     In one example, the stop member includes a body having a surface that extends between a first end and a second end and a bumper that partially covers the surface. For example, the first end includes a first mounting section for removably affixing the body in a first orientation on the gripper assembly, and the second end includes a second mounting section for removably affixing the body in a second orientation on the gripper assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates example gripper assemblies in an example industrial setting. 
         FIG. 2  illustrates an example gripper assembly having a bumper stop in one possible location. 
         FIG. 3  illustrates the example bumper stop in another possible location. 
         FIG. 4  illustrates the example bumper stop in a stored location. 
         FIG. 5A  illustrates an example rectangular bumper stop. 
         FIG. 5B  illustrates a top view of the example rectangular bumper stop. 
         FIG. 6  illustrates an example cylindrical bumper stop. 
         FIG. 7  illustrates an example gripper assembly having a cover that supports a bumper stop. 
         FIG. 8  illustrates an example of the bumper stop supported between the cover and the support. 
         FIG. 9  illustrates an example of the bumper stop cantilevered from the support. 
         FIG. 10  illustrates a selected portion of the cover shown in  FIG. 7  having an opening there through for identifying a location of the bumper stop. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  schematically illustrates selected portions of several gripper assemblies  10  used in an example industrial setting to grip and move work pieces  12  (shown schematically). The gripper assemblies  10  may be used in a variety of different configurations than that shown. As an example, the gripper assemblies  10  are coupled to extended arms  14 , which are secured to a rail  16 . An adapter arm  18  is secured to the rail  16 . An automated machine  20 , such as a robot, moves the adapter arm  18 , the extended arms  14 , and the gripper assemblies  10  to desired positions to retrieve and deposit the work pieces  12 , such as between work stations. 
       FIGS. 2-4  illustrate an example gripper assembly  10  having an adjustable bumper stop  40  for limiting opening of the gripper jaws  42   a  and  42   b . In this example, the gripper assembly  10  includes an actuator  44 , such as a pneumatic or hydraulic fluid-driven actuator, having a reciprocating piston (not shown) therein that linearly moves a piston rod  46 . The actuator  44  includes ports  48   a  and  48   b  for receiving fluid from a fluid source to actuate the actuator  44 . It is to be understood that other types of actuators may alternatively be used. 
     A distal end (relative to the actuator  44 ) of the piston rod  46  includes a cam head  50  having cam pins  52  (one shown) extending laterally therefrom relative to the direction of movement of the piston rod  46 . In this example, each of the cam pins  52  includes a roller  54  that is received within a cam slot  56  of a respective gripper jaw  42   a  or  42   b.    
     The cam head  50  moves linearly within a support  58  attached to the actuator  44 . In this example, the support  58  includes pivot bosses  60  (one shown) extending laterally therefrom for pivotally supporting the respective gripper jaws  42   a  and  42   b . The support  58  includes a plurality of mount locations  62   a ,  62   b , and  62   c , such as recessed slots in the illustrated example, for securing the bumper stop  40 . Although three mount locations  62   a ,  62   b , and  62   c  are shown, it is to be understood that more or less than three may also be used. Given this description, one of ordinary skill in the art will recognize alternative gripper assembly configurations that will benefit from the examples disclosed herein. 
     The mount locations  62   a ,  62   b , and  62   c  provide a variety of different possible locations for attaching the bumper stop  40  to the support  58 . In the disclosed example, the location  62   a  corresponds to a 45° open position of the gripper jaws  42   a  and  42   b  ( FIG. 3 ). The location  62   b  corresponds to a 22° open position of the gripper jaws  42   a  and  42   b  ( FIG. 2 ). The location  62   c  corresponds to a storage position for the bumper stop  40  where the bumper stop  40  does not interact with the jaws  42   a  and  42   b  to limit opening ( FIG. 4 ). Given this description, one of ordinary skill in the art will recognize that different mount locations than shown may be selected during a design stage to obtain different degrees of opening, for example. The opening of the jaws  42   a  and  42   b  can also be changed by using jaws having different shaped cam slots. 
     In operation, the actuator  44  moves the piston rod  46  forward in the illustrated figures to open the gripper jaws  42   a  and  42   b . As the gripper jaws  42   a  and  42   b  open, at least one of the jaws  42   a  and  42   b  encounters the bumper stop  40 , which limits further rotation of the gripper jaws  42   a  and  42   b  about their respective pivot bosses  60 . By adjusting the location of the bumper stop  40  between the various mount locations  62   a ,  62   b , or  62   c , one can provide a desired degree of jaw opening. It is to be understood that a bumper stop  40  can be used for each respective jaw  42  and  42   b  or to stop only one of the jaws  42   a  or  42   b  since stopping one jaw would stop both in the example gripper configuration. 
     Referring to  FIGS. 5A and 5B , the bumper stop  40  includes a body  64  having side surfaces  65   a  and  65   b  that extend between ends  66   a  and  66   b . In this example, the bumper stop  40  includes pads  67   a  and  67   b  that partially cover the respective side surfaces  65   a  and  65   b . The pads  67   a  and  67   b  are made of a resilient material, such as a polymer. In one example, the polymer is an elastomer that cushions impact of the jaws  42   a  and  42   b.    
     The pads  67   a  and  67   b  in the disclosed example have nominally equivalent thicknesses. However, in other examples, different thicknesses may be used to provide different degrees of jaw opening depending on the orientation of the bumper stop  40 . That is, orienting the bumper stop  40  such that a relatively thicker one of the pads  67   a  or  67   b  impacts the jaws  42   a  or  42   b  to provide a smaller degree of jaw opening, while orienting a relatively thinner one of the pads  67   a  or  67   b  to impact the jaws  42   a  or  42   b  would provide a larger degree of jaw opening. 
     The pads  67   a  and  67   b  leave portions of the side surfaces  65   a  and  65   b  exposed at end  66   a , end  66   b , or both. The unexposed portion or portions of the ends  66   a  and  66   b  function as mounting sections (e.g., tabs) that are receivable into the recessed slots of the mount locations  62   a ,  62   b , or  62   c . In other words, although the figures show both ends  66   a  and  66   b  exposed to function as mounting sections, alternatively only one of the ends  66   a  or  66   b  may be exposed such that the bumper stop  40  includes only one mounting section. The mounting section or sections and the recessed slots provide a tight fit that securely attaches the bumper stop  40  to the support  58 . The size of the exposed portions may vary, depending on the needs of a particular gripper assembly. 
     In the illustrated example, the bumper stop  40  is symmetrical relative to central orthogonal axes A and B such that the bumper stop  40  functions identically whether end  66   a  or end  66   b  is received into the recessed slots of the mount locations  62   a ,  62   b , or  62   c  (for equivalent pad  67   a  and  67   b  thicknesses). 
     As can be appreciated, the body  64  in the illustrated example is rectangular, which provides the benefit of relatively planar faces for bonding or otherwise securing the pads  67   a  and  67   b  to the side surfaces  65   a  and  65   b . Alternatively, the shape may be different. For example,  FIG. 6  illustrates a bumper stop  40 ′ that is similar to the bumper stop  40  but includes a body  64 ′ that is cylindrical. In this example, a surface  65 ′ extends between ends  66   a ′ and  66   b ′, and a pad  67 ′ partially covers the surface  65 ′. As can be appreciated, circular openings would be used rather than recessed slots at the mount locations  62   a ,  62   b , and  62   c  to mount the bumper stop  40 ′. Given this description, one of ordinary skill in the art will recognize alternative body shapes to meet their particular needs. 
     Optionally, as illustrated in  FIG. 7 , covers  70  are secured on each lateral side of the gripper assembly  10  using corresponding fasteners  72  (one shown) attached to the respective pivots  60  (one shown). Alternatively, the covers  70  may be attached to the actuator  44 . Each of the covers  70  includes an inside surface  74  and an outside surface  76  relative to the support  58 . 
     Referring also to  FIG. 8 , the inside surface  74  of the cover  70  includes cover mount locations  76   a ,  76   b , and  76   c  that correspond to the mount locations  62   a ,  62   b , and  62   c  of the support  58 . Thus, when one end of the bumper stop  40 ,  40 ′ is received into one of the mount locations  62   a ,  62   b , or  62   c , and the cover  70  is subsequently attached onto the gripper assembly  10 , the other end of the bumper stop  40 ,  40 ′ is received into the corresponding cover mount location  76   a ,  76   b , or  76   c  of the cover  70 . The bumper stop  40 ,  40 ′ is thereby supported on each end. 
     Alternatively, as shown in  FIG. 9 , the cover  70  may not include the mount locations  76   a ,  76   b , and  76   c . That is, the bumper stop  40 ,  40 ′ may be cantilevered from the mount locations  62   a ,  62   b ,  62   c  of the support  58  without being supported by the cover  70 . Although the bumper stop  40 ,  40 ′ may fit tightly into the corresponding mount locations  62   a ,  62   b , and  62   c , the cover  70  prevents the bumper stop  40 ,  40 ′ from dislodging from the mount locations  62   a ,  62   b , and  62   c  due to impact from the jaw  42 , for example. The cover  70  may abut the bumper stop  40 ,  40 ′ to limit movement of the bumper stop  40 ,  40 ′ outwards from the mount locations  62   a ,  62   b , and  62   c  to thereby prevent dislodging. 
     The bumper stop  40 ,  40 ′ provides the benefit of being able to easily and conveniently change the degree to which the gripper jaws  42   a  and  42   b  are able to open without having to disassemble a large number of components of the gripper assembly  10 . For example, to move the bumper stop  40 ,  40 ′ from the mount location  62   a  to the mount location  62   b , one of the fasteners  72  is removed to enable removal of the cover  70 . The bumper stop  40 ,  40 ′ is then manually removed from the mount location  62   a  and placed within the mount location  62   b  before replacing the cover  70  and tightening the fastener  72 . In examples where the gripper assembly  10  does not include covers  70 , the bumper stop  40 ,  40 ′ can be removed from any of the mount locations  62   a ,  62   b , or  62   c  and placed within another of the mount locations  62 ,  62   b , or  62   c  without having to disassemble any components of the gripper assembly. Furthermore, since the bumper stops  40 ,  40 ′ may be attached to the support  58  without using fasteners, the bumper stops  40 ,  40 ′ can be quickly and easily adjusted. 
     Referring to  FIG. 10 , the cover  70  optionally includes one or more openings  82  that extend through the outer surface  76 . In this example, the opening  82  corresponds to the cover mount location  76   a . The opening  82  allows an operator to visually determine whether the bumper stop  40 ,  40 ′ is located at the mount location  62   a  by looking through the opening  82 . Alternatively, the bumper stop  40 ,  40 ′ extends through the opening  82  to allow visual determination. Likewise, the cover  70  may include similar openings corresponding to the cover mount location  76   b  and  76   c.    
     Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.