Abstract:
An end of arm tool has a mounting bracket mounting the end of arm tool to the robot arm for movement therewith and has a plurality of operating mechanisms mounted to the mounting bracket, a plurality of gripping devices each operatively connected to a respective operating mechanism and movable along a path, and a plurality of individual motors each operatively connected to a respective gripping device for moving the respective gripping device along its respective path. At least one programmable controller for operating the motors is provided to adjust the positions of the gripping devices along their respective paths to one of a plurality of predetermined positions established by the controller for gripping the article and to position the end of arm tool adjacent the article so that at least one of the gripping devices grips the article.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates in general to robotic arms and end of arm tools for use in picking up and moving articles to or from a specific location. 
     Robotic arms with end of arm tooling are used in many applications in many industries. Often these devices are controlled by a programmable controller to do a repetitive task with the end of arm tooling being manually set in a fixed position to repetitively pick up and release articles. If the robotic arm and end of arm tooling are to be used in a different situation, such as moving a different shape of article than the previous one, the end of arm tool usually has to be manually reconfigured for that purpose. If this reconfiguration has to occur often, the cost of labor and the down time for utilization of the equipment can be significant. 
     SUMMARY OF THE INVENTION 
     This invention relates to end of arm tooling for a robotic arm which together are programmable to change their configurations and operations to any one of a multiple of preprogrammed configurations and operations. 
     In one aspect of the present invention a method of controlling an end of arm tool mounted on a robotic arm for placing or retrieving an article is provided, comprising providing an end of arm tool having a plurality of operating mechanisms, each operating mechanism supporting a separate gripping device each movable by its respective operating mechanism along a separate elongated path spaced from the paths of the other gripping devices; providing a plurality of motors at least one motor operatively connected to a respective gripping device for moving that gripping device along its respective path; using at least one programmable controller programmed to operate the motors so as to adjust the positions of the gripping devices along their respective paths to one of a plurality of predetermined positions established by the controller for gripping the article and to position the end of arm tool adjacent the article so that at least one of the gripping devices grips the article; and moving the arm so as to move the article. In another aspect of the invention, the method may include making the separate paths of the gripping mechanisms extend longitudinally in a common plane. In a further aspect, the method may include providing each operating mechanism with a bracket movable by the at least one motor and mounting the respective gripping device to the bracket for movement with the bracket, and further may include providing each motor with a stepping mechanism controlled by the at least one controller for positioning the respective gripping device at one of the predetermined locations. 
     The invention may also include one form of an apparatus comprising an end of arm tool having a mounting bracket for mounting the end of arm tool on the robotic arm; a plurality of operating mechanisms mounted on the mounting bracket; and a plurality of gripping devices one each supported by a respective operating mechanism, each gripping device being independently movable by its respective operating mechanism along a separate elongated path spaced from the paths of the other gripping devices. Such an apparatus may also include each operating mechanism having at least one motor operatively connected to the respective gripping device for moving the respective gripping device along its respective path. Such an apparatus may further include each operating mechanism having a bracket movable by the at least one motor and the respective gripping device being secured to the bracket for movement with the bracket. Such an apparatus may yet further include at least one programmable controller for operating the motors so as to adjust the positions of the gripping devices along their respective paths to one of a plurality of predetermined positions established by the controller for gripping the article and to position the end of arm tool adjacent the article so that at least one of the gripping devices grips the article. Such an apparatus may also include each motor having a stepping mechanism controlled by at least one controller for positioning the respective gripping device at one of several predetermined locations. The apparatus may further include the elongated paths being linear and extending in a common plane. Yet further the apparatus may include the operating mechanisms being substantially identical and each independently pivotable in the common plane containing their elongated paths. The apparatus may also include a fastener associated with each operating mechanism for holding the operating mechanism in fixed position in the common plane after the operating mechanism has been pivoted. 
     The invention may include another form of an apparatus comprising an end of arm tool for attachment to a robotic arm, comprising a mounting bracket for mounting the end of arm tool on the robotic arm; a plurality of adjustable operating mechanisms mounted on the mounting bracket; a plurality of gripping devices one each associated with a respective operating mechanism and movable along a path to a desired location; and a plurality of motors at least one of which is operatively connected to a respective gripping device for moving that gripping device along that gripping device&#39;s respective path. Such an apparatus may also include each operating mechanism having a bracket movable by the respective motor and the respective gripping device being secured to the bracket for movement with the bracket. The apparatus may also include at least one programmable controller for operating the motors so as to adjust the positions of the gripping devices along their respective paths to one of a plurality of predetermined positions established by the controller for gripping the article and to position the end of arm tool adjacent the article so that at least one of the gripping devices grips the article. Such an apparatus may further include each motor having a stepping mechanism controlled by the at least one controller for positioning the respective gripping device at one of several predetermined locations. The apparatus may also include the operating mechanisms being substantially identical and pivotable in the common plane containing their paths. Such apparatus may further include a fastener associated with each operating mechanism for holding the operating mechanism in fixed position in the common plane after the operating mechanism has been pivoted. 
     Yet a further apparatus of the present invention may include an assembly of a robot arm and end of arm tool, comprising a robot arm movable relative to an article; an end of arm tool, having a mounting bracket mounting the end of arm tool to the robot arm for movement therewith and having a plurality of operating mechanisms mounted to the mounting bracket, a plurality of gripping devices each operatively connected to a respective operating mechanism and movable along a path, and a plurality of individual motors each operatively connected to a respective gripping device for moving the respective gripping device along its respective path; and at least one programmable controller for operating the motors so as to adjust the positions of the gripping devices along their respective paths to one of a plurality of predetermined positions established by the controller for gripping the article and to position the end of arm tool adjacent the article so that at least one of the gripping devices grips the article. Such an apparatus may also include each operating mechanism having a bracket movable by the respective motor and the respective gripping device being secured to the bracket for movement with the bracket. Such an apparatus may further include each motor having a stepping mechanism controlled by at least one controller for positioning the respective gripping device at one of the several predetermined locations. Such an apparatus may yet further include the paths of movement of the gripping devices being linear and extending in a common plane. This apparatus may also include the operating mechanisms being substantially identical and pivotable in the common plane containing their paths. The apparatus may also include a fastener associated with each operating mechanism for holding the operating mechanism in fixed position in the common plane after the operating mechanism has been pivoted. 
     Still other aspects of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described preferred embodiments of this invention, simply by way of illustration of some modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments and its several details are capable of modification in various aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a first embodiment of an end of arm tool of the present invention; 
         FIG. 2  is a back perspective view of the embodiment of  FIG. 1 ; 
         FIG. 3  is a front view of the first embodiment showing in phantom line the range of swinging movement of multiple operating mechanisms of the first embodiment; 
         FIG. 4  is a top view of the first embodiment of an end of arm tool; 
         FIG. 5  is a bottom view of the first embodiment of an end of arm tool; 
         FIG. 6  is a right side view of the first embodiment with a robot arm and controller shown schematically; 
         FIG. 7  is a perspective view of a second embodiment of an end of arm tool in accordance with the present invention; 
         FIG. 8  is a bottom view of the embodiment of  FIG. 7 ; 
         FIG. 9  is a right side view of the embodiment of  FIG. 7 ; and 
         FIG. 10  is a right side view of the embodiment of  FIG. 7  including a robot arm and controller shown schematically. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, there is illustrated in  FIG. 1  a first embodiment of the apparatus of the present invention generally designated by the numeral  10  which is an end of arm tool for a robot mechanism. Tool  10  includes four basic operating mechanisms  12 ,  14 ,  16  and  18 , which are identical in construction. It is to be understood that more or fewer operating mechanisms may be used depending on the desired use. Taking operating mechanism  12  as an example, it includes a motor  20  which can be, for example, a slide table type stepping motor such as that designated as a series LXP from SMC Corporation, and which is illustrated in the figures of the first embodiment of the invention. This motor  20  basically includes a housing  22  and a bracket  24  supported by a lead screw (not shown) driven by a stepping motor  26 . Bracket  24  can be moved longitudinally back and forth along housing  22  by rotation of the lead screw. It is to be understood that any one of a large number of other types of motors or other devices may be used to move the gripping device to a desired location. Other examples include pneumatic, hydraulic and electric mechanical devices. Bracket  24  can be used to support a gripping device of any desired type, such as the vacuum gripping device  128  shown in  FIG. 7  in connection with a second embodiment described later herein, and thus move the gripping device to a desired location along the longitudinal axis of housing  22 . Although a linear, straight line motion is shown, it is to be understood that the motion can be perpendicular to the length of the housing. Also, the motion can be along curved lines, rotational, or complex to follow along different directional vectors. Such movement would enable the gripping device to be moved in any desired 3D space and be aimed in any desired orientation. The gripping device can be any device suitable for griping, holding or manipulating objects, and can operate using pneumatic, hydraulic, magnetic or electric mechanical principles. 
     Each of the operating mechanisms  12 ,  14 ,  16  and  18  is mounted to a mounting bracket  30  which is used to mount the end of arm tool  10  to a robotic arm  32  (see  FIG. 6 ). Robotic arm  32  can be of any desired type and mounting bracket  30  can be of an appropriate configuration to mate with the desired robotic arm  32  and provide the desired stability. In the embodiment of  FIG. 1  the mounting bracket  30  is constructed of two substantially identical plates  34  and  36  which are secured together in spaced parallel relation by four pins  38 ,  40 ,  42  and  44 . In the embodiment of  FIG. 1 , the operating mechanism  12  is pivotably mounted to mounting bracket  30  by a mounting plate  46  having a hole through which pin  38  passes so that plate  46  is free to rotate about pin  38 . Plate  46  is secured to housing  22  so that housing  22  is free to pivot laterally with plate  46  through approximately 90 degrees as shown by the phantom arcuate lines in  FIG. 3 . A locking screw  48  passes through arcuate slots  50  and  52  in plates  34  and  36 , respectively, and through a hole in plate  46 . Slots  50  and  52  are formed with their center of radius on pin  38 . Locking screw  48  can be tightened to hold operating mechanism  12  in any desired position within the pivotal range of the operating mechanism  12 . All of the operating mechanisms  12 ,  14 ,  16  and  18  can thus be independently pivoted, each through approximately 90 degrees, and then locked in position for use. Generally, the operating mechanisms are symmetrically positioned for use about the center of the end of arm tool  10  so that the center of gravity is in the center of the tool  10 . 
     A programmable controller  54  (see  FIG. 6 ) is operatively connected to the robotic arm  32  and the operating mechanisms  12 ,  14 ,  16  and  18 . The programmable controller  54  can be either a single controller or multiple controllers, as desired. The controller  54  can be the same as the controller for the robotic arm  32 , or can be a different controller. The controller  54  is generally programmed to provide a multiplicity of motions for both the robotic arm  32  and the operating mechanisms  12 ,  14 ,  16  and  18 , depending on the operating conditions required. The controller and associated software for the operation of the operating mechanisms  12 ,  14 ,  16  and  18  can be added to existing robotic mechanisms, or in the alternative, the software can be added to existing controllers of robotic mechanisms. The controller is optionally provided with various input and output devices and other suitable features for connection and communication with other devices associated with the robotic mechanisms. 
     The programmable controller  54  can be programmed to move the robotic arm to any one of a number of operating stations where operations are to be performed and to perform different operations with the end of arm tool  10  at each of those stations. For example, if the robotic arm  32  and end of arm tool  10  are to be used in an article manufacturing environment where various different shaped articles are to be removed from respective molds, the programmable controller  54  can be programmed to move the robot arm  32  to each of the respective molds and to operate one or more of the operating mechanisms  12 ,  14 ,  16  and  18  so as to position one or more of their respective gripping devices, such as vacuum gripping device  128 , along the longitudinal axis of its respective housing and move it into engagement with the article in a particular mold and activate the gripping device, such as by operating a vacuum source (not shown) operatively connected to the gripping device to thus remove the article from the mold. 
     It is contemplated that the robotic arm  32  and end of arm tool  10  of the present invention can be used where not all of the operating mechanisms  12 ,  14 ,  16  and  18  are used to pick up one article. For example, one operating mechanism such as  12  may be used to pick up one article while another operating mechanism  14  can be used to pick up a different article, even a different shaped article, from a different mold. It is also contemplated, for example, to use two or more operating mechanisms  12 ,  14 ,  16  and  18  of the end of arm tool  10  to pick up one article and one or more other operating mechanisms  12 ,  14 ,  16  and  18  to pick up a different shaped article from another mold and then deposit all of the articles thus picked up at other predetermined locations which are preprogrammed into the programmable controller  54 . It is contemplated that various combinations of movements can be programmed into the programmable controller to fit the needs of a particular installation. The robotic arm  32  and end of arm tool  10  can likewise be used to pick up different articles from multiple locations and place these articles in respective molds. 
     It is further contemplated that the robotic arm  32  and end of arm tool  10  can be used in many environments other than mold making. For example, it is contemplated that the present invention can be used to remove different shaped articles or packages from conveyors or storage bins and move them to other locations by using one or more of the operating mechanisms  12 ,  14 ,  16  and  18 , and thus can include moving multiple articles simultaneously or sequentially. 
     The programmable controller  54  can be programmed with several operating modes in advance of use of the robotic arm  32  and end of arm tool  30 . The programmable controller  54  can be configured to receive an input from an operator or from a signaling device that indicates to the controller what mode of operation the end of arm tool is to operate in for the next movement and then move the robotic arm  32  and end of arm tool  30  accordingly. In any of the above described examples of use of the present invention or wherever the present invention is suitable for use, the programmable controller  54  can be programmed to perform such operations in the sequences desired. 
     Referring now to a second preferred embodiment as shown in  FIGS. 7-10 , there is illustrated an end of arm tool generally designated by the numeral  100 . Tool  100  includes four basic operating mechanisms  112 ,  114 ,  116  and  118 , which are identical in construction and similar to the operating mechanisms of the first preferred embodiment described above. As with the first embodiment, it is to be understood that more or fewer operating mechanisms may be used depending on the desired use. Taking operating mechanism  112  as an example, it includes a motor  120  which can, for example, be the same slide table type stepping motor  20 , described with respect to the first embodiment. This motor  120  basically includes a housing  122  and a bracket  124  supported by a lead screw (not shown) driven by a stepping motor  126 . It is to be understood that any one of a large number of other types of motors may be used as the motor  120 . Bracket  124  is different than bracket  24  of the first embodiment, but is also used to support a gripping device of any desired type, such as the vacuum gripping device  128  shown in  FIG. 7 . Bracket  124  extends over the housing  122  toward the center of tool  100  so that the gripping devices  128  of operating mechanisms  112 ,  114 ,  116  and  118  will be closer together than if they were mounted at the end of housing  122 . 
     Each of the operating mechanisms  112 ,  114 ,  116  and  118  is mounted to a mounting bracket  130  which is used to mount the end of arm tool  100  to a robotic arm  132 . As with the first embodiment, robotic arm  132  can be of any desired type and mounting bracket  130  can be of an appropriate configuration to mate with the desired robotic arm  130 . In the embodiment of  FIGS. 7-9 , the mounting bracket  130  is constructed of two plates  134  and  136  which are secured together in spaced parallel relation by four pairs of columns, three of which, pairs of columns  138 ,  140 ,  142  are shown while a fourth pair of columns symmetrically positioned around the mounting bracket from the other pairs of columns are not shown. In the embodiment of  FIGS. 7-10 , operating mechanisms  112 ,  114 ,  116  and  118  are mounted in fixed positions to mounting bracket  130 . The operating mechanisms of this embodiment are separated by 90 degrees and are thus symmetrically positioned about the center of the end of arm tool  100  so that the center of gravity is in the center of the tool  100 . 
     A programmable controller  154  (see  FIG. 10 ) is operatively connected to the robotic arm  132  and the operating mechanisms  112 ,  114 ,  116  and  118 . Programmable controller  154  can be identical to programmable controller  54  and all of the various functions described above with regard to programmable controller  54  can be carried out by controller  154  as well and will therefore not be described in detail again. Likewise, the various environments described above with respect to the first embodiment in which that embodiment can be utilized apply equally to this second embodiment. 
     It is also contemplated by the present invention that unlike the above two described embodiments the operating mechanisms may operate along paths different from linear paths as shown. For example, it is contemplated that the operating mechanisms may allow the gripping devices to move along curvilinear paths and in more than one plane. Furthermore, although the operating environment has been described in connection with mold making operations and article or package movement, the invention should not be considered as usable only in those environments. 
     In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiments. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope. 
     When introducing elements of the present invention or the embodiment(s) thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.