Abstract:
A gripper tip for use with a gripper assembly includes a first gripping surface located at least partially within a first plane and a second gripping surface located at least partially within a second plane that is transverse to the first plane. The first gripping surface includes a first gripping height relative to a first attachment portion associated with the first gripping surface. The second gripping surface includes a second gripping height relative to a second attachment portion associated with the second gripping surface, and the second gripping height is greater than the first gripping height.

Description:
RELATED APPLICATIONS 
   The application claims priority to U.S. Provisional Application No. 60/776,452, which was filed on Feb. 24, 2006. 

   BACKGROUND OF THE INVENTION 
   This invention generally relates to automated handling equipment. More particularly, this invention relates to an actuated gripper device. 
   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. 
   Typically, the jaws include removable gripper tips or pads that include teeth to facilitate gripping of the work pieces. The pads are removable and replaceable with different pads to provide different teeth or to accommodate different sizes or shapes of work pieces. For example, the pad thickness corresponds to the distance between the jaws in the open position. Thicker pads provide a shorter distance to accommodate thinner work pieces and thinner pads provide a longer distance to accommodate thicker work pieces. 
   Although conventional gripper pads are effective for clamping and transferring work pieces or other objects, using replaceable pads complicates use of the handling equipment, and pad replacement is time-consuming. Additionally, pads that are not in use require storage space and may become lost. 
   Accordingly, there is a need for a single gripper pad that is adjustable to accommodate work pieces of varying thicknesses. This invention addresses those needs and provides enhanced capabilities while avoiding the shortcomings and drawbacks of the aforementioned art. 
   SUMMARY OF THE INVENTION 
   An example gripper tip for use with a gripper assembly includes a first gripping surface located at least partially within a first plane and a second gripping surface located at least partially within a second plane that is transverse to the first plane. The first gripping surface includes a first gripping height relative to a first attachment portion associated with the first gripping surface. The second gripping surface includes a second gripping height relative to a second attachment portion associated with the second gripping surface. 
   An example gripper tip system for use with a gripper assembly includes two gripper tips. A first gripper tip is removably attachable to a gripper jaw in at least two different orientations relative to the gripper jaw. A second gripper tip is removably attachable to an opposed gripper jaw in at least two different orientations relative to the opposed gripper jaw. The different orientations of the gripper tips correspond to different heights of the gripper tips relative to the gripper jaws. 
   An example gripper assembly includes a first gripper jaw, a second gripper jaw, an automated actuator for moving the gripper jaws, a first gripper tip, and a second gripper tip. The gripper tips are removably attachable to the gripper jaws in at least two different orientations to provide at least three different possible jaw opening sizes between the first gripper tip and the second gripper tip for a given position of the gripper jaws. 
   These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates example gripper assemblies for moving work pieces between work stations. 
       FIG. 2  illustrates an example gripper assembly from  FIG. 1 . 
       FIG. 3  illustrates a gripper pad of the gripper assembly shown in  FIG. 2 . 
       FIG. 4  illustrates a cross-section of the gripper pads shown in  FIG. 2 . 
       FIG. 5  illustrates a side view of the gripper pads shown in  FIG. 2 . 
       FIG. 6A  illustrates one possible orientation combination of the example gripper pads. 
       FIG. 6B  illustrates a second possible orientation combination of the example gripper pads. 
       FIG. 6C  illustrates a third possible orientation combination of the example gripper pads. 
       FIG. 7  illustrates a side view of an example gripper having gripper pads that are oriented to accommodate a work piece. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  illustrates selected portions of several gripper assemblies  10  used in an example industrial setting to grip and move a work piece  12  (shown schematically). The gripper assemblies  10  may be used in a variety of different configurations and different settings from that shown. In the illustrated example, the gripper assemblies  10  are coupled to extended arms  14 , which are each 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. 
   Referring to  FIG. 2 , each of the gripper assemblies  10  includes an actuator  30 , such as a pneumatic or hydraulic actuator. It is to be understood that other types of actuators may also be used. The actuator selectively reciprocates a piston (not shown) to open or close gripper jaws  32   a  and  32   b  in a known manner. In this example, each of the gripper jaws  32   a  and  32   b  includes an end portion  34  having a recess  36  for mounting a gripper pad  38  (i.e. a tip). The gripper pads  38  of the disclosed example are adjustable between several different orientations to provide a variety of different possible spacings between the gripper jaws  32   a  and  32   b  for accommodating work pieces  12  of varying thicknesses t ( FIG. 1 ). 
   Referring to  FIG. 3 , each of the gripper pads  38  includes a first pad section  40   a  and a second pad section  40   b . The pad sections  40   a  and  40   b  are connected to opposite sides of a mounting portion  42 . In this example, each of the pad sections  40   a  and  40   b  are rectangular block-shaped and have a first gripping surface  44   a  on one side of the block and a second gripping surface  44   b  on another side that is directly adjacent to the side of the first gripping surface  44   a . In the disclosed example, the directly adjacent sides having the gripping surfaces  44   a  and  44   b  are generally perpendicular to each other. This provides the benefit of only having to rotate the gripper pad  38  90° to switch between the different orientations provided by the two gripping surfaces  44   a  and  44   b.    
   The gripping surfaces  44   a  and  44   b  each include a patterned texture, such as a toothed pattern, that provides traction for gripping the work piece  12 . The patterned texture may be formed on or from the gripping surfaces  44   a ,  44   b , such as by machining. Alternatively, the patterned textures may be provided by separate pieces, such as rubber or metal pads, that are attached to the respective gripping surfaces  44   a ,  44   b . In the disclosed example, the patterned texture of each of the gripping surfaces  44   a  and  44   b  is the same. Optionally, different patterned textures may be used where different degrees of traction are desired. 
   In the illustrated example, the mounting portion  42  is positioned between the pad sections  40   a  and  40   b . The mounting portion  42  includes a first extended face  46   a  associated with the first gripping surface  44   a  and a second extended face  46   b  associated with the second gripping surface  44   b . Each of the extended faces  46   a  and  46   b  protrude beyond the surfaces the pad sections  40   a  and  40   b . This allows the extended faces  46   a  and  46   b  to be received at least partially into the recess  36  of the gripping jaw  32   a  or  32   b . so that the mountinn portion  42  functions as a pilot to orient the gripper tip  38 . In some examples, the extended faces  46   a  and  46   b  are sized to fit relatively tightly within the recesses  36 . In some examples though, there may be some play between the extended faces  46   a  and  46   b  and the recesses  36 . This provides the advantage of locking the gripping pads  38  within the recesses  36  and prevents relative rotation between the gripping pad  38  and the jaw  32   a  or  32   b.    
   As can be appreciated from  FIGS. 3 and 4 , the mounting portion  42  also includes a first opening  48   a  that extends through the first extended face  46   a  and a second opening  48   b  that extends through the second extended face  46   b . In the illustrated example, the openings  48   a  and  48   b  are threaded to receive a threaded fastener for securing the gripping pads  38  on the jaws  32   a  and  32   b.    
     FIG. 5  shows a side view of the gripper pads  38  to illustrate a difference in thickness of the gripping pads  38  along different directions that provides adjustability for varying work piece  12  thicknesses t ( FIG. 1 ). In this example, each of the gripping surfaces  44   a  and  44   b  has an associated gripper pad thickness. The first gripping surface  44   a  has a pad thickness t 1  and the second gripping surface  44   b  has an associated pad thickness t 2 . In this example, the pad thickness t 1  is greater than the pad thickness t 2 . Optionally, the gripping surfaces  44   a  and  44   b  may be designated with an identification number, such as the numbers “0” and “2” shown in the figure. This provides the benefit of visual indication of the gripper pad  38  orientation. 
   Referring to  FIGS. 6A ,  6 B, and  6 C, the gripper pads  38  may be secured within the recesses  36  of the jaws  32   a  and  32   b  using either the first extended face  46   a  or the second extended face  46   b . The first extended face corresponds to the first gripping surface  44   a  and the second extended face corresponds to the second gripping surface  44   b . That is, the selected extended face  46   a  or  46   b  controls which gripping surface  44   a  or  44   b  will be used for gripping. 
   The adjustability of the gripping pads  38  along with the different pad thicknesses t 1  and t 2 , provide three combinations of gripper pad orientations to accommodate three different work piece  12  thicknesses t. In the example shown in  FIG. 6A , each of the gripper pads  38  is shown schematically secured to the jaw  32   a . This orients both gripper pads  38  along the pad thickness t 1  and provides a first distance D 1  between the gripper pads  38  when the jaws  32   a  and  32   b  are closed to accommodate relatively thin work pieces  12 . 
   In the example shown in  FIG. 6B , one of the gripper pads  38  is secured with the second extended face  46   b  to orient the pad along the thickness t 2 , which is less than the pad thickness t 1  in the disclosed example. The combination of using one pad along thickness t 1  with the other pad along thickness t 2  provides a second, intermediate distance D 2  between the gripper pads  38 . This provides the benefit of accommodating a work piece of intermediate thickness t, but thicker than a work piece that can be accommodated by the example shown in  FIG. 6A . 
   In the example shown in  FIG. 6C , both the gripper pads  38  are secured with the second extended face  46   b  to orient the pads  38  along the t 2  direction. This provides a distance D 3  between the gripper pads  38  to accommodate a relatively thicker work piece  12  than can be accommodated in the examples shown in  FIG. 6A  or  6 B. 
   In one example, the gripper pad  38  thicknesses t 1  and t 2  are selected to provide a desired distance range between the jaws  32   a  and  32   b . For example, the t 1  and t 2  thicknesses are selected such that in the “0-0” orientation (i.e., the visual indication of the orientation) shown in  FIG. 6A , the jaws  32   a  and  32   b  can accommodate work piece  12  thicknesses t in the range of 0 mm to 2 mm. In the “0-2” orientation shown in  FIG. 6B , the jaws  32   a  and  32   b  can accommodate work piece  12  thicknesses t in the range of 2 mm to 4 mm. In the “2-2” orientation shown in  FIG. 6C , the jaws  32   a  and  32   b  can accommodate work piece  12  thicknesses t in the range of 4 mm to 6 mm. Given this description, one of ordinary skill in the art will recognize gripper pad  38  thicknesses to meet their particular needs. 
   In the example shown in  FIG. 7 , the gripper pads  38  may also be used to accommodate work pieces of varying shapes. For example, work piece  12 ′ includes a bent end  60 . To grip the work piece  12 ′, the gripper  10  requires more space toward the lower jaw  32   b  (between the jaws  32   a  and  32   b ) to accommodate the bent end  60 . The gripper pads  38  are oriented to provide the additional space. The bottom gripper pad  38  in the figure is oriented in the “0” orientation along its t 1  thickness and the top gripper pad  38  is oriented in the “2” orientation along its t 2  thickness such that a gripping plane P between the gripper pads  38  is offset from a centerline C of the gripper  10  (e.g., the centerline is the central axis of the cylindrical actuator  30 ). The offset griping plane P provides a shift of the work piece  12 ′ upwards in the figure to accommodate the length of the bent end  60  within the bottom jaw  32   b . That is, upon closing, the bottom jaw  32   b  does not contact or interfere with the work piece  12 ′. 
   The disclosed example gripper pads  38  therefore provide the advantage of allowing an operator to adjust the gripper assembly  10  to accommodate work pieces  12 ,  12 ′ of varying thicknesses or shapes without having to replace or substitute different gripper pads. In the disclosed examples, the operator need only to remove the fastener (e.g., a threaded fastener) from the gripper pad  38 , rotate the gripper pad 90°, and secure the fastener to the gripper pad  38  to adjust the gripping range of the jaws  32   a  and  32   b . In some examples, this eliminates the need for replacement gripper pads, which require storage space and are vulnerable to misplacement in some prior gripper assemblies. 
   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.